Switching mechanism, flow path switching mechanism, and liquid ejection device

Abstract

To provide a changeover device which does not need a position sensor.SOLUTION: This invention is a changeover mechanism, which changes over the rotational position of a second body of rotation 103 to a predetermined rotational position by making a first body of rotation 106 execute, with a drive source, normal and reverse rotations of performing normal rotation and reverse rotation, where at least one of gaps a first gap S1 is formed larger than a second gap S2 as another gap. When a center angle two protrusions 103b, 103d constituting the first gap S1 form with respect to a rotational center RC1 is a first angle θ1, and the largest angle out of a center angle two protrusions constituting the second gap S2 form with respect to a rotational center RC1 is a second angle θ2, the drive source positions an engagement part 105c within the first gap S1 by making the first body of rotation 106 repeatedly execute normal and reverse rotations at a rotation angle smaller than the first angle θ1 and larger than the second angle θ2.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a switching mechanism that switches the rotational position of a rotor, a flow path switching mechanism including the switching mechanism, and a liquid ejection device including the flow path switching mechanism. [Background technology]

[0002] The image forming apparatus described in Patent Document 1 includes a switching mechanism for a rotary valve that selectively connects a conduit to a suction pump depending on a rotation position. The switching mechanism includes a ratchet gear that is integrally provided on a rotary shaft of the rotary valve, an arm member that is rotatably supported on the rotary shaft, and a ratchet pawl that is rotatably supported on the arm member. When the arm member rotates counterclockwise, the ratchet pawl meshes with the ratchet gear, causing the rotary valve to rotate counterclockwise together with the arm member, thereby switching the conduit connected to the suction pump.

[0003] The image forming apparatus described in Patent Document 1 further includes a position indicating member provided on the ratchet gear and a position detector for detecting the position indicating member. The position detector detects the rotational position of the rotary valve. The arm member is an example of a first rotating body, the ratchet gear is an example of a second rotating body, the ratchet pawl is an example of an engagement portion, and the image forming apparatus is an example of a liquid ejection device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2002-200774 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the switching mechanism described in Patent Document 1, the liquid ejection device has a position detector that detects the rotational position of the rotary valve in case the rotational position of the rotary valve becomes unknown due to an unintended event. This causes a problem that the liquid ejection device becomes complicated. [Means for solving the problem]

[0006] The switching mechanism for solving the above problem includes a first rotating body that receives a driving force transmitted from a driving source and performs forward and reverse rotation, and a second rotating body that rotates around a rotation center of the first rotating body and has a plurality of convex portions provided on an outer periphery at intervals in the direction of rotation, the first rotating body includes an engaging portion that is displaceable along the outer periphery of the second rotating body, and when the first rotating body rotates forward, the engaging portion engages with the convex portion, thereby causing the second rotating body to rotate forward together with the first rotating body, and when the first rotating body rotates reversely, the engaging portion moves along the outer periphery of the second rotating body to suppress the reverse rotation of the second rotating body, and the driving source is configured to rotate the second rotating body forward and to rotate the first rotating body in the reverse direction. A switching mechanism switches the rotational position of the second rotating body to a predetermined rotational position by causing the first rotating body to perform a forward / reverse operation that alternates between forward and reverse rotation, wherein at least one first interval among the intervals is formed larger than the other intervals, and when a central angle formed by two convex portions constituting the first interval with respect to the rotation center is defined as a first angle and the maximum angle formed by two convex portions constituting the other intervals with respect to the rotation center is defined as a second angle, the driving source positions the engagement portion within the first interval by repeatedly causing the first rotating body to perform the forward / reverse operation at a rotational angle smaller than the first angle and equal to or greater than the second angle.

[0007] The flow path switching mechanism for solving the above problem includes the above switching mechanism, a first flow path, and two or more flow paths different from the first flow path, and a rotary valve rotates to switch between the two or more different flow paths. and a rotary valve capable of switching a flow path communicating with the first flow path, the rotary valve being rotatable together with the second rotor, and when a predetermined convex portion among the plurality of convex portions of the second rotor is located at a predetermined position, the first flow path is connected to any one of the two or more different flow paths.

[0008] A liquid ejection device that solves the above problem comprises a liquid ejection section that ejects liquid from a nozzle, a supply flow path that supplies liquid to the liquid ejection section from a liquid container that contains liquid, a cap capable of forming a closed space in which the nozzle opens, a branch flow path having one end connected to the middle of the supply flow path, a discharge flow path having one end connected to the cap, a drive source, and the flow path switching mechanism, wherein the pump is a suction pump, the other end of the branch flow path is connected to a second flow path of two or more flow paths different from the first flow path, and the other end of the discharge flow path is connected to a third flow path of two or more flow paths different from the first flow path. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view showing a multifunction peripheral including a liquid ejection device according to first and second embodiments. [Diagram 2] FIG. 1 is a schematic cross-sectional side view showing a liquid ejection device including a flow path switching mechanism. [Diagram 3] FIG. 2 is a perspective view showing a configuration of a flow path switching mechanism in the first embodiment. [Figure 4] FIG. 2 is an exploded perspective view showing the configuration of a flow path switching mechanism in the first embodiment. [Diagram 5] FIG. [Figure 6] 4 is a front view showing a state in which the first rotating body rotates forward at a second rotation angle. FIG. [Figure 7] 11 is a front view showing a state in which the first rotating body rotates in the reverse direction at a second rotation angle. FIG. [Figure 8] 11 is a front view showing a state after the first rotating body has rotated in the reverse direction at a second rotation angle. FIG. [Figure 9] FIG. 4 is a front view showing a state in which the first rotating body rotates forward at a first rotation angle. [Figure 10]FIG. 4 is a front view showing a state in which the first rotating body rotates in the reverse direction at a first rotation angle. [Figure 11] FIG. 4 is a front view showing a state in which the engagement portion is located within a first interval. [Figure 12] FIG. 11 is a front view showing a state in which the engagement portion is located within the second interval. [Figure 13] FIG. [Figure 14] FIG. 4 is a front view showing the drive gear and the first gear. [Figure 15] FIG. 4 is a front view showing the drive gear and the second gear. [Figure 16] FIG. [Figure 17] FIG. 4 is a front view showing a state in which the second gear is locked to the first rotating body. [Figure 18] FIG. 4 is a front view showing a state in which the second gear is locked to the first rotating body. [Figure 19] FIG. [Figure 20] FIG. 4 is a front view showing a state in which the first gear and the second gear rotate. [Figure 21] FIG. 4 is a front view showing a state in which the drive gear and the second gear mesh with each other. [Figure 22] FIG. 4 is a front view showing a state in which the drive gear and the first rotor are engaged with each other. [Diagram 23] FIG. 4 is a front view showing a state in which the drive gear and the first rotor are disengaged from each other. [Figure 24] FIG. 13 is a front view showing a state in which the drive gear rotates after disengaging from the second gear. [Diagram 25] FIG. 13 is a front view showing a state in which a flow path switching operation is started. [Figure 26] FIG. 11 is a front view showing a state in which the first rotating body rotates forward in the flow path switching operation. [Figure 27] FIG. 11 is a front view showing a state in which a first rotating body rotates in a reverse direction during a flow path switching operation. [Figure 28] FIG. [Figure 29] FIG. 4 is a front view showing a state in which the first rotor has moved to a pump release operating position. [Diagram 30]FIG. [Diagram 31] FIG. 4 is a front view showing a state in which the pump is returning from the pump release operation position to the operation start position. [Diagram 32] FIG. 11 is an exploded perspective view showing the configuration of a flow path switching mechanism in a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, a first embodiment and a second embodiment of a switching mechanism, a flow path switching mechanism, and a liquid ejection device will be described with reference to the drawings. It is an inkjet printer that prints characters, images, etc. onto a medium by ejecting liquid such as ink.

[0011] (First embodiment) <About the configuration of the multifunction printer> 1, the multifunction device 11 includes a liquid ejection device 12 and an image reading device 13 disposed on the liquid ejection device 12. The image reading device 13 covers the upper side of the liquid ejection device 12, and the multifunction device 11 has a generally rectangular parallelepiped shape as a whole.

[0012] In Fig. 1, the multifunction device 11 is placed on a horizontal plane, and the direction of gravity is indicated by the Z axis, and directions along the horizontal plane perpendicular to the direction of gravity are indicated by the X and Y axes. The X, Y, and Z axes intersect with each other. In this embodiment, the X, Y, and Z axes are perpendicular to each other. In the following description, the direction along the X axis is the scanning direction X, the direction along the Y axis is the transport direction Y, and the direction along the Z axis is the vertical direction Z.

[0013] An operation panel 17 is provided on the front surface of the liquid ejection device 12. The operation panel 17 has an operation section 15 such as buttons for performing various operations on the multifunction device 11, and a display section 16 for displaying information on the liquid ejection device 12 and the multifunction device 11. Furthermore, a holder 19 for holding at least one liquid container 18 is provided on the right side of the operation panel 17. The holder 19 constitutes a part of the housing 20, and holds at least one liquid container 18 therein.

[0014] <Configuration of the liquid ejection device> 2, the liquid ejection device 12 includes a liquid ejection unit 30 that ejects liquid from a nozzle 31, a liquid storage unit 50, an air bubble discharge mechanism BS, and a carriage 33 that can move back and forth in the scanning direction X. The carriage 33 carries the liquid ejection unit 30, the liquid storage unit 50, and the air bubble discharge mechanism BS. The liquid storage unit 50 has a storage chamber 51 that can store liquid supplied from the liquid container 18 to the liquid ejection unit 30. The air bubble discharge mechanism BS is configured to be able to discharge air above the storage chamber 51 of the liquid storage unit 50.

[0015] The liquid ejection device 12 includes a liquid supply device 26 that supplies liquid from a liquid container 18 that contains liquid to a liquid ejection unit 30. The liquid supply device 26 is composed of a supply flow path 27 that supplies liquid from the liquid container 18 to the liquid ejection unit 30, and a liquid storage unit 50 provided midway through the supply flow path 27. The supply flow path 27 includes a first supply path 27a, which is a portion upstream of the liquid storage unit 50, and a second supply path 27b, which is a portion downstream of the liquid storage unit 50. The second supply path 27b is provided on the carriage 33. The liquid in the liquid storage unit 50 is sent to the liquid ejection unit 30 by the second supply path 27b.

[0016] The liquid ejection device 12 includes a maintenance device 40 that performs maintenance on the liquid ejection unit 30. The maintenance device 40 includes a cap 41 that is provided so as to be movable relative to the liquid ejection unit 30, and a discharge flow path 42 that is connected to the cap 41. The cap 41 is located below the liquid ejection unit 30. The cap 41 is capable of receiving liquid that is ejected or discharged from the nozzle 31 of the liquid ejection unit 30 for maintenance.

[0017] The cap 41 is configured to be movable between a retracted position separated from the liquid ejection unit 30 and a capping position in contact with the nozzle surface 30a, which is the surface where the nozzles 31 of the liquid ejection unit 30 open. When the cap 41 is in the capping position, the cap 41 forms a closed space between the nozzle surface 30a and the cap 41, where the nozzles 31 open. In other words, the cap 41 is capable of forming a closed space where the nozzles 31 open.

[0018] The maintenance device 40 includes a pump 45 as a suction pump. comprises a discharge recovery flow path 46, a waste liquid storage section 47 that stores waste liquid recovered from the discharge recovery flow path 46, a flow path switching mechanism 44 that selectively switches a flow path connected to the discharge recovery flow path 46, and a drive source that drives the pump 45 and the flow path switching mechanism 44. The upstream end of the discharge recovery flow path 46 is connected to the other end 45b of the pump 45, so that the discharge recovery flow path 46 communicates with the pump 45. The downstream end of the discharge recovery flow path 46 is connected to the waste liquid storage section 47, so that the discharge recovery flow path 46 communicates with the waste liquid storage section 47. One end 45a of the pump 45 is connected to the flow path switching mechanism 44 through the tube 43, so that the pump 45 communicates with the flow path switching mechanism 44. In other words, the waste liquid storage section 47 and the flow path switching mechanism 44 communicate with each other.

[0019] The flow path switching mechanism 44 and the cap 41 are connected through the discharge flow path 42. One end 42a of the discharge flow path 42 is connected to the cap 41. The maintenance device 40 also has a branch flow path 96 branching from the supply flow path 27. The flow path switching mechanism 44 and the air bubble discharge mechanism BS are connected through the branch flow path 96. One end 96a of the branch flow path 96 is connected to the middle of the supply flow path 27. The other end 42b of the discharge flow path 42 and the other end 96b of the branch flow path 96 are connected to the flow path switching mechanism 44. The flow path switching mechanism 44 selectively switches between a state in which the discharge and recovery flow path 46 is connected to the discharge flow path 42, a state in which the discharge and recovery flow path 46 is connected to the branch flow path 96, and a state in which the discharge and recovery flow path 46 is not connected to either flow path. The liquid discharge device 12 includes a suction device 97 that applies negative pressure to the flow path connected to the discharge and recovery flow path 46. The suction device 97 utilizes the pump 45 of the maintenance device 40 as its negative pressure source.

[0020] When the discharge recovery flow path 46 is connected to the discharge flow path 42, the maintenance device 40 drives the pump 45 with the liquid discharge unit 30 in a capped state, thereby introducing negative pressure into the closed space formed between the cap 41 and the nozzle surface 30a. As a result, the maintenance device 40 discharges foreign matter such as air bubbles in the liquid in the liquid discharge unit 30 from the nozzle 31 together with the liquid, and sends it to the waste liquid storage unit 47.

[0021] When the discharge / recovery flow path 46 is connected to the branch flow path 96, the maintenance device 40 drives the pump 45 to introduce negative pressure into the upper part of the storage chamber 51 in the liquid storage unit 50 via the air bubble discharge mechanism BS. If there are air bubbles in the upper part of the storage chamber 51, the air bubbles are sucked through the branch flow path 96 by the introduced negative pressure, and are removed from the storage chamber 51. Then, the liquid containing the air bubbles is sent to the waste liquid storage unit 47.

[0022] In the flow path switching mechanism 44, the switching operation of the rotational position of a rotary valve (not shown) is controlled by the control unit 100. The rotary valve is configured to be switchable to switching positions including a switching position where the negative pressure from the pump 45 is introduced into the storage chamber 51 in the liquid storage unit 50 via the air bubble discharge mechanism BS, and a switching position where the negative pressure from the pump 45 is introduced into the cap 41. The flow path switching mechanism 44 will be described in detail later.

[0023] <Configuration of flow path switching mechanism> As shown in FIG. 3, the flow path switching mechanism 44 includes a rotary valve 102. The rotary valve 102 includes a housing 101 that is a fixed part. The housing 101 has two or more flow paths different from the first flow path 101b and the first flow path 101b. That is, the rotary valve 102 has two or more flow paths different from the first flow path 101b and the first flow path 101b. The outer peripheral surface 102a shown in FIG. 4 is rotatably fitted to the inner peripheral surface 101a shown in FIG. 4, so that the rotating part of the rotary valve 102 is configured to be rotatable with respect to the housing 101. The rotation of the rotating part of the rotary valve 102 with respect to the housing 101 that is a fixed part is referred to as the rotation of the rotary valve 102. In this embodiment, the rotary valve 102 has the first flow path 101b, the second flow path 101c, and the third flow path 101d. That is, the rotary valve 102 has a first flow path 101b and two flow paths 101c and 101d that are different from the first flow path 101b.

[0024] The flow path switching mechanism 44 is configured to be able to switch a flow path that communicates with the first flow path 101b among two or more flow paths different from the first flow path 101b by rotating the rotary valve 102 about a rotation center RC1. In this embodiment, the flow path switching mechanism 44 is configured to be able to switch a flow path that communicates with the first flow path 101b among the second flow path 101c and the third flow path 101d.

[0025] The first flow path 101b and one end 45a of the pump 45 shown in Fig. 2 are connected by the tube 43 shown in Fig. 2, so that the one end 45a of the pump 45 communicates with the first flow path 101b. The other end 96b of the branch flow path 96 shown in Fig. 2 is connected to a second flow path 101c of the two or more flow paths different from the first flow path 101b, and the other end 42b of the discharge flow path 42 shown in Fig. 2 is connected to a third flow path 101d of the two or more flow paths different from the first flow path 101b.

[0026] As shown in FIG. 4, the flow path switching mechanism 44 has a switching mechanism 120. The switching mechanism 120 includes a first rotor 106. The first rotor 106 receives a driving force transmitted from a driving source 114, the rotation angle of which is controlled by the control unit 100 shown in FIG. 2, and performs forward and reverse rotation. The method of transmitting the driving force from the driving source 114 to the first rotor 106 will be described later. Furthermore, the switching mechanism 120 includes a second rotor 103. The second rotor 103 rotates around a rotation center RC1 of the first rotor 106, and a plurality of convex portions are provided on the outer periphery 103e at intervals in the rotation direction. In this embodiment, three convex portions 103b, 103c, and 103d are provided on the outer periphery 103e of the second rotor 103 at intervals in the rotation direction. The switching mechanism 120 switches the rotation position of the second rotor 103 to a predetermined rotation position. The switching operation of the switching mechanism 120 will be described later.

[0027] An inner peripheral surface 106a of the first rotating body 106 and an inner peripheral surface 103a of the second rotating body 103 are rotatably fitted to a central axis (not shown). Therefore, the first rotating body 106 and the second rotating body 103 can rotate separately around the same rotation center RC1.

[0028] The first rotating body 106 includes an engaging member 105. The engaging member 105 has a hole 105a, and the first rotating body 106 has a shaft 106b. The hole 105a is rotatably fitted to the shaft 106b, so that the engaging member 105 is configured to be rotatable around the shaft 106b. Furthermore, the engaging member 105 has an engaging portion 105c. The first rotating body 106 has a first biasing member 104. The first biasing member 104 biases the engaging portion 105c toward the outer periphery 103e of the second rotating body 103. In other words, the first rotating body 106 includes an engaging portion 105c that is displaceable along the outer periphery 103e of the second rotating body 103.

[0029] As shown in FIG. 4, the engaging portion 105c has a side surface 105f and a slope 105g. Also, the convex portions 103b, 103c, and 103d each have a side surface 103f and a slope 103g. When the first rotating body 106 rotates in the forward rotation direction W1, the side surface 105f and the side surface 103f come into contact with each other as shown in FIG. 3. When the first rotating body 106 further rotates in the forward rotation direction W1, a pressing force acts in the vertical direction of the side surface 103f, and a reaction force acts in the vertical direction of the side surface 105f. Since the side surface 105f and the side surface 103f are both surfaces extending in the radial direction with respect to the rotation center RC1, the reaction force does not include a component that rotates the engaging member 105 in the direction D1 away from the rotation center RC1. Therefore, while the side surface 105f and the side surface 103f are in contact with each other, the side surface 105f presses the side surface 103f by a pressing force, causing the first rotating body 106 to rotate the second rotating body 103. The state in which the side surface 105f and the side surface 103f are in contact with each other is referred to as the engagement portion 105c engaging with the convex portions 103b, 103c, and 103d. That is, when the first rotating body 106 rotates in the forward rotation direction W1, the engagement portion 105c engages with the convex portions 103b, 103c, and 103d, causing the second rotating body 103 to rotate in the forward rotation direction W1 together with the first rotating body 106. Note that the rotation in the forward rotation direction W1 that continues continuously and intermittently is referred to as forward rotation.

[0030] As shown in FIG. 4, when the first rotor 106 rotates in the reverse direction W2, the inclined surface 105g and the inclined surface 105b are inclined. The surface 103g comes into contact with the first rotor 106. When the first rotor 106 is further rotated in the reverse direction W2, a pressing force acts in the vertical direction of the inclined surface 103g, and a reaction force acts in the vertical direction of the inclined surface 105g. Since the side surface 105f and the side surface 103f are both surfaces that have an angle with respect to a plane extending in the radial direction from the rotation center RC1, the reaction force includes a component that rotates the engaging member 105 in a direction D1 away from the rotation center RC1. Therefore, the first rotor 106 does not rotate the second rotor 103, and the engaging portion 105c is displaced along the inclined surface 103g in a direction D1 away from the rotation center RC1. When the first rotor 106 is further rotated in the reverse direction W2, the engaging portion 105c is displaced along the side surface 103f in a direction D2 approaching the rotation center RC1. That is, when the first rotating body 106 rotates in the reverse direction W2, the engaging portion 105c moves along the outer periphery 103e of the second rotating body 103, thereby suppressing the second rotating body 103 from rotating in the reverse direction W2. Note that the rotation in the reverse direction W2 that continues continuously and intermittently is referred to as a reverse rotation.

[0031] The rotary valve 102 is rotatable together with the second rotor 103. Therefore, the flow path switching mechanism 44 is configured so that the rotary valve 102 does not rotate relative to the housing 101 when the engagement portion 105c moves along the outer periphery 103e of the second rotor 103. More specifically, the rotational torque of each of the rotary valve 102 and the housing 101 is set so that it is greater than the rotational torque applied to the second rotor 103 when the engagement portion 105c overcomes the convex portions 103b, 103c, and 103d from the inclined surface 103g side.

[0032] In this embodiment, the first biasing member 104 is a tension spring having hook portions 104a, 104b at both ends. The hook portion 104a is hooked to a hooked portion 106c of the first rotating body 106, and the hook portion 104b is hooked to a hooked portion 105b of the engaging member 105. This causes the engaging portion 105c to be biased toward the outer periphery 103e of the second rotating body 103. The engaging member 105 may be biased toward the outer periphery 103e of the second rotating body 103 by a compression spring.

[0033] The rotary valve 102 rotates together with the second rotor 103 in a state where the engagement portion 105c is engaged with a predetermined convex portion among the multiple convex portions 103b, 103c, and 103d of the second rotor 103. As a result, when the predetermined convex portion is located at a predetermined position, the first flow path 101b communicates with one of two or more flow paths different from the first flow path 101b. For this reason, the convex portions 103b, 103c, and 103d are provided at positions corresponding to the switching positions of the rotary valve 102.

[0034] In this embodiment, when the rotary valve 102 rotates together with the second rotor 103 with the engagement portion 105c engaged with the protrusion 103b, the first flow path 101b and the second flow path 101c communicate with each other when the protrusion 103b is located at the position of the first flow path 101b shown in Fig. 4. More specifically, the first flow path 101b communicates with the groove end portion 102c located on the outer circumferential surface 102a, and the second flow path 101c communicates with the groove end portion 102d located on the outer circumferential surface 102a, so that the first flow path 101b and the second flow path 101c communicate with each other through the groove 102b of the rotary valve 102. In addition, when the rotary valve 102 further rotates together with the second rotor 103 with the engagement portion 105c engaged with the convex portion 103c, the first flow path 101b and the third flow path 101d are connected when the convex portion 103c is positioned at the position of the first flow path 101b shown in Figure 4.

[0035] Furthermore, when the rotary valve 102 further rotates together with the second rotor 103 with the engagement portion 105c engaged with the convex portion 103d, the first flow path 101b does not communicate with any of the flow paths when the convex portion 103d is located at the position of the first flow path 101b shown in Fig. 4. In other words, when the rotary valve 102 rotates together with the second rotor 103 with the engagement portion 105c engaged with a predetermined convex portion, the first flow path 101b may not communicate with the flow paths 101c and 101d different from the first flow path 101b when the predetermined convex portion is located at a predetermined position.

[0036] When the rotary valve 102 rotates together with the second rotor 103 to a predetermined rotation position, The rotary valve 102 may be configured so that the circumferential surface 102a blocks flow paths other than the flow path communicating with the first flow path 101b. Even when the flow path switching mechanism 44 has three or more flow paths other than the first flow path 101b, the rotary valve 102 is configured so that the outer circumferential surface 102a blocks flow paths other than a predetermined flow path communicating with the first flow path 101b, thereby making it possible to communicate the first flow path 101b with the predetermined flow path.

[0037] <Regarding the placement of protrusions> As shown in FIG. 5, the second rotating body 103 has a plurality of protrusions provided on the outer periphery 103e at intervals in the rotation direction. At least one of the intervals, a first interval S1, is formed to be larger than the other intervals. In this embodiment, the one first interval S1 is formed to be larger than a second interval S2 as the other two intervals. The protrusions 103b and 103c form the second interval S2, the protrusions 103c and 103d form the second interval S2, and the protrusions 103d and 103b form the first interval S1. In this specification, the interval between the protrusions in the rotation direction of the second rotating body 103 refers to the interval between the side surfaces 103f of the protrusions shown in FIG. 4.

[0038] The central angle formed by the two convex portions constituting the first interval S1 with respect to the rotation center RC1 is the first angle θ1, and the maximum angle among the central angles formed by the two convex portions constituting the other intervals with respect to the rotation center RC1 is the second angle θ2. The other intervals are smaller than the first interval S1. In this embodiment, the central angle formed by the convex portion 103d and the convex portion 103b constituting the first interval S1 with respect to the rotation center RC1 is the first angle θ1. And the central angle formed by the convex portion 103b and the convex portion 103c constituting the second interval S2 with respect to the rotation center RC1 is the second angle θ2. And the central angle formed by the convex portion 103c and the convex portion 103d constituting the second interval S2 with respect to the rotation center RC1 is also the second angle θ2.

[0039] <Switching operation> As shown in FIG. 5, the switching mechanism 120 starts a switching operation. For example, when the engaging portion 105c is engaged with the convex portion 103b, the first rotating body 106 at the position shown in FIG. 5 rotates forward together with the second rotating body 103 in the forward direction W1 at the second rotation angle Φ2 shown in FIG. 6 to the position shown in FIG. 6. More specifically, as shown in FIG. 6, the engaging portion 105c presses the convex portion 103b, so that the first rotating body 106 rotates the second rotating body 103 to a predetermined rotation position. Then, the first rotating body 106 at the position shown in FIG. 6 rotates in the reverse direction W2 at the second rotation angle Φ2 shown in FIG. 7, which is the same rotation angle as the forward rotation angle, so that only the first rotating body 106 rotates to the position shown in FIG. 7. At this time, as shown in FIG. 7, the engaging portion 105c is displaced in the direction D1 away from the rotation center RC1, so that the engaging portion 105c passes over the convex portion 103c. The second rotation angle Φ2 is the same as the second angle θ2, which is the central angle formed by the convex portion 103b and the convex portion 103c with respect to the rotation center RC1. At this time, the switching mechanism 120 changes from the state shown in Fig. 5 in which the engaging portion 105c engages with the convex portion 103b to the state shown in Fig. 7 in which the engaging portion 105c engages with the convex portion 103c. Then, the switching operation ends.

[0040] That is, the switching mechanism 120 rotates the rotary valve 102 shown in FIG. 4 in the forward direction W1 at the second rotation angle Φ2, and changes the state in which the engaging portion 105c engages with the convex portion 103b to a state in which the engaging portion 105c engages with the convex portion 103c. When the rotary valve 102 is located at the rotation position shown in FIG. 4 in the state in which the switching operation starts in FIG. 5, so that the first flow path 101b shown in FIG. 4 does not communicate with any flow path, the first flow path 101b and the second flow path 101c shown in FIG. 4 communicate with each other in the state in which the switching operation ends in FIG. 7. The second rotation angle Φ2 is set so that the first flow path 101b and the second flow path 101c shown in FIG. 4 communicate with each other in the state in which the switching operation ends in FIG. 7. In this way, the switching mechanism 120 switches the rotation position of the second rotor 103 to a predetermined rotation position, and the flow path communicating with the first flow path 101b is switched.

[0041] By performing the switching operation again, the switching mechanism 120 changes from the state shown in FIG. 7 in which the engaging portion 105c engages with the convex portion 103c to the state shown in FIG. 8 in which the engaging portion 105c engages with the convex portion 103d. When the first flow path 101b and the second flow path 101c shown in FIG. 4 communicate with each other in the state where the switching operation is started, the first flow path 101b and the third flow path 101d shown in FIG. 4 communicate with each other in the state where the switching operation is ended. The second rotation angle Φ2 is set so that the first flow path 101b and the third flow path 101d shown in FIG. 4 communicate with each other in the state where the switching operation is ended. In this way, the switching mechanism 120 switches the rotation position of the second rotor 103 to a predetermined rotation position, thereby switching the flow path that communicates with the first flow path 101b.

[0042] In the state shown in FIG. 8, by further performing the switching operation, the switching mechanism 120 changes from the state shown in FIG. 8 in which the engaging portion 105c engages with the convex portion 103d to the state shown in FIG. 10 in which the engaging portion 105c engages with the convex portion 103b. When the engaging portion 105c is in the state in which it engages with the convex portion 103d, the first rotating body 106 in the position shown in FIG. 8 rotates forward together with the second rotating body 103 in the forward rotation direction W1 at the first rotation angle Φ1 shown in FIG. 9, so that the second rotating body 103 rotates to the position shown in FIG. 9. Then, only the first rotating body 106 in the position shown in FIG. 9 rotates reversely in the reverse direction W2 at the first rotation angle Φ1 shown in FIG. 10, which is the same rotation angle as the forward rotation angle, so that the first rotating body 106 rotates to the position shown in FIG. 10. When the first flow path 101b and the third flow path 101d shown in FIG. 4 are in communication with each other at the start of the switching operation, the first flow path 101b shown in FIG. 4 is not in communication with any flow path at the end of the switching operation. The first rotation angle Φ1 is set so that the first flow path 101b shown in FIG. 4 is not in communication with any flow path at the end of the switching operation and the switching mechanism 120 returns to the state shown in FIG. 5 where the switching operation is started for the first time. In other words, the switching mechanism 120 returns to the state shown in FIG. 5 where the switching operation is started for the first time by repeating the switching operation. In this way, the flow path in communication with the first flow path 101b is switched by the switching mechanism 120 switching the rotation position of the second rotor 103 to a predetermined rotation position.

[0043] In this way, the switching mechanism 120 is a switching mechanism 120 that switches the rotation position of the second rotating body 103 to a predetermined rotation position by causing the driving source 114 shown in Fig. 4 to execute a forward / reverse operation in which the first rotating body 106 rotates forward and reverse in sequence. In the following description, the operation of rotating forward and reverse in sequence is simply referred to as a "forward / reverse operation." Also, one forward rotation and one reverse rotation is the smallest unit of operation in the forward / reverse operation.

[0044] In the switching operation, the rotation angle in the forward rotation in the forward / reverse operation and the rotation angle in the reverse rotation in the forward / reverse operation may not be the same. For example, the rotation angle may be set to be larger than the rotation angle of the forward rotation performed immediately before the reverse rotation. More precisely, if the engagement portion 105c passes over a predetermined convex portion during the reverse rotation and does not pass over a convex portion located on the reverse direction W2 side of the predetermined convex portion, the engagement portion 105c may be located at a position away from the predetermined convex portion on the reverse direction W2 side after the reverse rotation. Even in such a case, the engagement portion 105c engages with the predetermined convex portion during the next forward rotation. Therefore, the engagement portion 105c presses the predetermined convex portion toward the forward rotation direction W1, so that the first rotating body 106 rotates forward in the forward rotation direction W1 together with the second rotating body 103. In this forward rotation, a rotation angle is set such that the second rotating body 103 rotates to a predetermined position, so that the rotation position of the second rotating body 103 can be switched to the predetermined rotation position even in the next switching operation. However, in order to simplify the control of the forward and reverse rotation operations, it is desirable that, in the switching operation, as in this embodiment, the rotation angle in forward rotation during forward and reverse rotation operation is the same as the rotation angle in reverse rotation during the forward and reverse rotation operation.

[0045] <About origin return operation> The origin return operation, which is an operation in which the switching mechanism 120 positions the second rotor 103 at a predetermined rotational position when the rotational position of the rotary valve 102 becomes unknown, will be described. The origin return operation includes a first operation in which the engaging portion 105c is disposed within the first interval S1, and a second operation in which the engaging portion 105c is disposed within the first interval S2. and a second operation in which the second rotor 103 is positioned at a predetermined rotational position from a state in which the second rotor 103 is disposed within the space S1. For example, when the rotational position of the rotary valve 102 becomes unknown due to an unintended event, the second rotor 103, which rotates together with the rotary valve 102, is positioned at a predetermined rotational position by the origin return operation.

[0046] First, a first operation in which the engaging portion 105c is disposed within the first interval S1 will be described. 11, when the engaging portion 105c is located within the first interval S1, the driving source 114 causes the first rotating body 106 to perform a forward / reverse operation at a rotation angle smaller than the first angle θ1 and equal to or larger than the second angle θ2. When the first rotating body 106 rotates forward in the forward rotation direction W1, even if the engaging portion 105c engages with the convex portion 103d, the engaging portion 105c presses the convex portion 103d, causing the first rotating body 106 to rotate the second rotating body 103. Therefore, when the forward rotation is completed, the engaging portion 105c remains located within the first interval S1.

[0047] The first rotating body 106 in this state rotates in the reverse direction W2 at a rotation angle equal to the rotation angle of the forward rotation and smaller than the first angle θ1. When the engaging portion 105c engages with the convex portion 103d during forward rotation, the engaging portion 105c remains positioned within the first interval S1 even if the first rotating body 106 in this state rotates in the reverse direction at a rotation angle smaller than the first angle θ1. When the engaging portion 105c does not engage with the convex portion during forward rotation, the first rotating body 106 in this state rotates in the reverse direction at the same rotation angle as the rotation angle of the forward rotation, and returns to the state before the forward / reverse operation. That is, the engaging portion 105c remains positioned within the first interval S1.

[0048] In other words, when the engagement portion 105c is positioned within the first interval S1, no matter how many times the drive source 114 causes the first rotating body 106 to perform forward and reverse operations at a rotation angle smaller than the first angle θ1 and greater than or equal to the second angle θ2, the engagement portion 105c remains positioned within the first interval S1.

[0049] As shown in FIG. 12, when the engaging portion 105c is located within the other interval, the driving source 114 causes the first rotating body 106 to perform a forward / reverse operation at a rotation angle smaller than the first angle θ1 and equal to or larger than the second angle θ2. When the first rotating body 106 rotates forward in the forward rotation direction W1, even if the engaging portion 105c engages with a convex portion, the engaging portion 105c presses the convex portion, causing the first rotating body 106 to rotate the second rotating body 103. Therefore, when the forward rotation is completed, the engaging portion 105c remains located within the other interval. In this embodiment, all the other intervals are the second intervals S2.

[0050] The first rotating body 106 in this state rotates in the reverse direction W2 at a rotation angle equal to the rotation angle of the forward rotation and equal to or greater than the second angle θ2. Since the second angle θ2 is the maximum angle among the central angles formed with respect to the rotation center RC1 by two convex portions constituting an interval smaller than the first interval S1, the engaging portion 105c overcomes at least one convex portion during the reverse rotation. That is, when the engaging portion 105c is located within another interval, if the forward / reverse rotation operation is performed once, the engaging portion 105c moves within one of the intervals on the reverse direction W2 side. Note that since the rotation angle is smaller than the first angle θ1, when the interval adjacent to the reverse direction W2 side is the first interval S1, the engaging portion 105c moves within the first interval S1.

[0051] When the destination interval is the first interval S1, no matter how many times the driving source 114 subsequently causes the first rotating body 106 to perform forward and reverse operations at a rotation angle smaller than the first angle θ1 and equal to or greater than the second angle θ2, the engagement portion 105c remains positioned within the first interval S1.

[0052] When the destination interval is another interval, the driving source 114 then causes the first rotating body 106 to perform forward and reverse operations at a rotation angle smaller than the first angle θ1 and equal to or greater than the second angle θ2, thereby moving the engagement portion 105c further within one of the intervals on the reverse direction W2 side.

[0053] That is, the driving source 114 causes the first rotating body 106 to repeatedly execute forward and reverse rotation at a rotation angle smaller than the first angle θ1 and equal to or larger than the second angle θ2. The number of repetitions is equal to or larger than the number of protrusions provided on the outer periphery 103e minus one. That is, the driving source 114 causes the first rotating body 106 to repeatedly execute forward and reverse rotation at that number of repetitions, thereby making it possible to position the engagement portion 105c within the first interval S1. The number of repetitions refers to the number of times the first operation is executed, which is an example of a forward and reverse operation in which forward and reverse rotations are performed once each.

[0054] In the first operation, the forward and reverse rotations in the forward and reverse rotations do not have to be the same. However, in the first operation when the engagement portion 105c is located within the first interval S1, the rotation angle is set so that the rotation angle in the forward rotation is equal to or greater than the rotation angle in the reverse rotation so that the engagement portion 105c does not go over the convex portion 103b during reverse rotation. For example, in the first operation, even when the rotation angle in the forward rotation is the average rotation angle of the first angle θ1 and the second angle θ2 and the rotation angle in the reverse rotation is the second angle θ2, the engagement portion 105c can be placed in the first interval S1. In addition, the rotation angle may be different for each forward and reverse rotation that is repeatedly performed. However, in the first operation, it is desirable that the rotation angle in the forward rotation and the rotation angle in the reverse rotation are the same as in this embodiment so that the control of the forward and reverse rotations is simple.

[0055] When the engaging portion 105c is located within the first interval S1 and at a position where it does not engage with the convex portion 103d during the first forward rotation, the second rotor 103 does not move at all even when the first action is performed. That is, even if the engaging portion 105c is located within the first interval S1, the rotational position of the second rotor 103 is not yet determined, and the rotational position of the rotary valve 102 remains unknown. Even in such a case, the second action is performed to position the second rotor 103 at a predetermined rotational position.

[0056] Next, a second operation will be described in which the second rotating body 103 is positioned at a predetermined rotational position from a state in which the engaging portion 105c is disposed within the first interval S1. 11, when the engaging portion 105c is located within the first interval S1, the driving source 114 causes the first rotating body 106 to perform forward and reverse rotation at a rotation angle equal to or greater than the first angle θ1. Because the rotation angle is greater than the first angle θ1, when the first rotating body 106 rotates forward in the forward rotation direction W1, the engaging portion 105c engages with the convex portion 103d, causing the engaging portion 105c to press the convex portion 103d. Therefore, the first rotating body 106 rotates the second rotating body 103 to a predetermined rotation position.

[0057] The first rotating body 106 in this state rotates in the reverse direction W2 at a rotation angle equal to the rotation angle of the forward rotation and a predetermined rotation angle equal to or greater than the first angle θ1. When the first rotating body 106 rotates in the reverse direction W2 at a rotation angle equal to or greater than the first angle θ1 from a state in which the engaging portion 105c engages with the convex portion 103d, the engaging portion 105c climbs over at least one convex portion. Therefore, the engaging portion 105c moves to within any interval on the reverse direction W2 side. Note that the rotation angle is set in a range equal to or greater than the first angle θ1 so that the engaging portion 105c moves within the predetermined interval during the second operation reverse rotation and engages with the predetermined convex portion when the second operation reverse rotation is completed.

[0058] In the forward rotation of the second operation, the rotary valve 102 can be rotated together with the second rotor 103 to a predetermined rotation position. In the reverse rotation of the second operation, the engagement portion 105c can be engaged with a predetermined protrusion. Then, with this state as the origin of the rotary valve 102, the above-mentioned switching operation is performed, thereby switching the flow path that communicates with the first flow path 101b. A specific example will be described below.

[0059] When the rotation angle in the second operation is the "first angle θ1", the switching mechanism 120 4, and the engaging portion 105c engages with the protrusion 103b. That is, when the rotation angle in the second operation is the "first angle θ1", the switching mechanism 120 switches the rotation position of the second rotor 103 to a rotation position shown in FIG. 4 where the first flow path 101b does not communicate with any of the flow paths. Then, with this state as the origin of the rotary valve 102, the above-mentioned switching operation is performed, and the flow path that communicates with the first flow path 101b is switched.

[0060] The rotation angle in the second operation may be "first angle θ1+second angle θ2". At that time, the switching mechanism 120 switches the rotation position of the second rotor 103 so that the convex portion 103d is located at a position symmetrical with the position of the first flow path 101b shown in FIG. 4 with respect to the rotation center RC1, and the engagement portion 105c engages with the convex portion 103c. That is, when the rotation angle in the second operation is "first angle θ1+second angle θ2", the switching mechanism 120 switches the rotation position of the second rotor 103 to a rotation position shown in FIG. 4 where the first flow path 101b and the second flow path 101c communicate with each other. Then, with this state as the origin of the rotary valve 102, the above-mentioned switching operation is further performed, thereby switching the flow path that communicates with the first flow path 101b.

[0061] The rotation angle in the second operation may be "first angle θ1+second angle θ2+second angle θ2". At that time, the switching mechanism 120 switches the rotation position of the second rotor 103 so that the convex portion 103d is located at the position of the second flow path 101c shown in FIG. 4 and the engagement portion 105c engages with the convex portion 103d. That is, when the rotation angle in the second operation is "first angle θ1+second angle θ2+second angle θ2", the switching mechanism 120 switches the rotation position of the second rotor 103 to a rotation position shown in FIG. 4 where the first flow path 101b and the third flow path 101d communicate with each other. Then, with this state as the origin of the rotary valve 102, the above-mentioned switching operation is further performed, thereby switching the flow path that communicates with the first flow path 101b.

[0062] In this way, when the engaging portion 105c is located within the first interval S1, the driving source 114 causes the first rotor 106 to perform a forward / reverse operation at a predetermined rotation angle equal to or greater than the first angle θ1, thereby switching the rotation position of the second rotor 103 to a predetermined rotation position. That is, even when the rotation position of the rotary valve 102 becomes unknown, the driving source 114 causes the first rotor 106 to perform the first operation and the second operation in sequence, thereby switching the rotation position of the second rotor 103 to a predetermined rotation position. Then, the flow path communicating with the first flow path 101b can be switched to the predetermined flow path.

[0063] In the second operation, the forward and reverse rotations in the forward and reverse rotation operation do not have to be the same rotation angle. The explanation of the second operation is the same as that of the switching operation described above, so the explanation will be omitted. In the second operation, too, it is desirable that the rotation angle of the forward rotation in the forward and reverse rotation operation is the same as the rotation angle of the reverse rotation, as in this embodiment, so that the control of the forward and reverse rotation operation is simple.

[0064] <Configuration of the suction device> As shown in FIG. 13, the suction device 97 includes a flow path switching mechanism 44. The flow path switching mechanism 44 includes a switching mechanism 120. The switching mechanism 120 includes a driving unit 119 that drives the switching mechanism 120. The driving unit 119 has a driving gear 109 as a driving rotor. The driving gear 109 is configured to be rotatable by receiving a driving force transmitted from a driving source 114, thereby driving the first rotor 106. The first rotor 106 receives a driving force transmitted from the driving source 114 via the driving gear 109. The driving source 114 is, for example, a stepping motor or a DC motor with an encoder, which can rotate forward and backward by controlling the rotation angle. Note that, when the driving source is a linear driving source that performs reciprocating linear motion, and the travel distance of the linear motion is controlled, and the linear motion is further converted into rotational motion to control the rotation angle, the driving source is synonymous with a driving source whose rotation angle is controlled.

[0065] The pump 45 includes a pump drive shaft 110 driven by a drive gear 109, a tube 112 through which liquid flows, and a roller 111 whose shaft 111a is supported by a bearing portion 110b of the pump drive shaft 110 and whose outer peripheral surface 111b pressurizes the tube 112. The drive gear 109 and the pump drive shaft 110 are configured to be rotatable about a rotation center RC2. The drive gear 109 receives a driving force transmitted from a drive source 114 to drive the pump 45. That is, the pump 45 receives the driving force from the drive source 114 via the drive gear 109. The drive gear 109 has a second engagement portion 109a. The pump drive shaft 110 included in the pump 45 has an engaged portion 110a that can engage with the second engagement portion 109a in the rotation direction. With the second engaging portion 109a engaged with the engaged portion 110a, the driving gear 109 rotates in a direction in which the second engaging portion 109a presses the engaged portion 110a, thereby driving the pump 45. The suction operation performed by driving the pump 45 will be described later.

[0066] The switching mechanism 120 includes a delay transmission mechanism 118. The delay transmission mechanism 118 is composed of a drive gear 109, a first gear 108, a second gear 107, a first rotating body 106, and a second biasing member 113. The delay transmission mechanism 118 delays the timing at which the first rotating body 106 starts to rotate. The second biasing member 113 biases the first gear 108 against the second gear 107. The first gear 108 and the second gear 107 are configured so that the frictional force acting between the surface of the first gear 108 that presses the second gear 107 and the surface of the second gear 107 that is pressed by the first gear 108 is high. In other words, the first gear 108 and the second gear 107 form a friction clutch 117. The operation of the delay transmission mechanism 118 will be described later.

[0067] <About the delay transmission mechanism> First, each gear will be described. 14, the first gear 108 is configured to be rotatable about a rotation center RC1. Teeth 109e of the drive gear 109 and teeth 108e of the first gear 108 mesh with each other, so that the rotation of the drive gear 109 is transmitted to the first gear 108. A rotating shaft (not shown) is fitted into the inner circumferential surface 108a, and the rotating shaft is fixed non-rotatably with respect to the first gear 108 by joints 108b and 108c.

[0068] As shown in FIG. 15, the second gear 107 is configured to be rotatable relative to the first gear 108 about a rotation center RC1 by having an inner circumferential surface 107a rotatably fitted onto a rotation shaft (not shown) fixed to the first gear 108.

[0069] The second gear 107 has a groove 107d having a concave shape on the surface that contacts the first rotating body 106. The groove 107d has engaged portions 107b, 107c that are engaged with the first rotating body 106. The second gear 107 further has a toothed portion 107m with teeth 107e arranged on the outer periphery, and a toothless portion 107n with no teeth 107e arranged on the outer periphery. Notches 107f, 107h are formed at both ends of the toothed portion 107m. Four teeth 107e including an end tooth 107g are arranged on the outer periphery of the notched portion 107f, and four teeth 107e including an end tooth 107i are arranged on the outer periphery of the notched portion 107h.

[0070] Teeth 109e of the drive gear 109 mesh with teeth 107e of the second gear 107, so that the rotation of the drive gear 109 is transmitted to the second gear 107. However, since the second gear 107 has a toothless portion 107n, depending on the rotation position of the second gear 107, the rotation of the drive gear 109 may not be transmitted to the second gear 107.

[0071] Even when the rotation of the drive gear 109 is not transmitted to the second gear 107, if the rotation torque of the second gear 107 is smaller than the transmission torque of the friction clutch 117 shown in FIG. 13, the second gear 107 rotates via the friction clutch 117 when the first gear 108 rotates. Furthermore, when the rotational torque of the second gear 107 is greater than the transmission torque of the friction clutch 117, even if the first gear 108 rotates, the friction clutch 117 slips and the second gear 107 does not rotate. In other words, when the rotation of the drive gear 109 is not transmitted to the second gear 107, if a load torque is generated on the second gear 107, the second gear 107 does not rotate even if the first gear 108 rotates.

[0072] As shown in FIG. 16, the first rotating body 106 is configured to be rotatable relative to the first gear 108 about a rotation center RC1 by having an inner circumferential surface 106a rotatably fitted onto a rotation shaft (not shown) fixed to the first gear 108.

[0073] The first rotating body 106 has a protruding locking portion 106d on the surface that contacts the second gear 107. The locking portion 106d locks the locked portions 107b and 107c of the second gear 107. The first rotating body 106 further has a toothed portion 106m with teeth 106e aligned on the outer periphery, and a toothless portion 106n with no teeth 106e aligned on the outer periphery. Notches 106f and 106h are formed at both ends of the toothed portion 106m. Four teeth 106e including end tooth 106g are aligned on the outer periphery of the notched portion 106f, and four teeth 106e including end tooth 106i are aligned on the outer periphery of the notched portion 106h.

[0074] The teeth 109e of the drive gear 109 mesh with the teeth 106e of the first rotor 106, so that the rotation of the drive gear 109 is transmitted to the first rotor 106. However, since the first rotor 106 has a tooth-missing portion 106n, depending on the rotation position of the first rotor 106, the rotation of the drive gear 109 may not be transmitted to the first rotor 106. The proportion of the outer periphery of the first rotor 106 that is occupied by the tooth-missing portion 106n is greater than the proportion of the outer periphery of the second gear 107 that is occupied by the tooth-missing portion 107n.

[0075] When the second gear 107 rotates, the locked portions 107b and 107c of the second gear 107 are locked to the locking portion 106d of the first rotating body 106, so that the first rotating body 106 is pulled by the second gear 107 and rotates.

[0076] Next, the relationship between the first rotor 106 and the second gear 107 will be described. 17, when the second gear 107 rotates in the forward rotation direction W1, the locked portion 107b is locked to the locking portion 106d, and the second gear 107 is locked to the first rotating body 106. When the second gear 107 further rotates in the forward rotation direction W1, the first rotating body 106 is pulled by the second gear 107 and rotates in the forward rotation direction W1 together with the second gear 107.

[0077] When the second gear 107 at the position shown in Fig. 17 is reversed in the reverse direction W2, the locked portion 107b moves away from the locking portion 106d, and only the second gear 107 rotates reversely in the reverse direction W2. When the second gear 107 rotates reversely in the reverse direction W2 by the same rotation angle as the oscillation angle Ψ shown in Fig. 17 to the position shown in Fig. 18, the locked portion 107c is locked by the locking portion 106d.

[0078] 18, when the second gear 107 rotates reversely in the reverse direction W2, the locked portion 107c is locked to the locking portion 106d, and the second gear 107 is locked to the first rotating body 106. When the second gear 107 further rotates reversely in the reverse direction W2, the first rotating body 106 is pulled by the second gear 107 and rotates reversely together with the second gear 107 in the reverse direction W2.

[0079] 18, the second gear 107 rotates in the forward direction W1, and the locked portion 107c moves away from the locking portion 106d, so that only the second gear 107 rotates in the forward direction W1. When the second gear 107 rotates in the forward direction W1 by the same rotation angle as the oscillation angle Ψ shown in FIG. 18 to the position shown in FIG. 17, the locked portion 107b is locked by the locking portion 106d.

[0080] In either state of Figures 17 and 18, the tooth-missing portions 106n and 107n are arranged so that the end tooth 107g is located on the forward rotation direction W1 side of the end tooth 106g, and the end tooth 107i is located on the reverse rotation direction W2 side of the end tooth 106i.

[0081] Next, the operation of the delay transmission mechanism 118 will be described. As shown in Fig. 19, when the driving gear 109 rotates in the forward direction W1, the first gear 108 shown in Fig. 13 rotates in the forward direction W1. At this time, the state of the first rotating body 106 and the second gear 107 is the state shown in Fig. 18, and the forward rotation direction W1, which is the rotation direction of the first gear 108, is the direction in which the locked portion 107c moves away from the locking portion 106d. Therefore, even if the driving gear 109 and the second gear 107 are not in mesh with each other, the rotation of the first gear 108 is transmitted to the second gear 107 by the friction clutch 117 shown in Fig. 13, so that the second gear 107 rotates in the forward direction W1 together with the first gear 108.

[0082] As shown in FIG. 20, when the second gear 107 rotates forward in the forward direction W1 due to the driving gear 109 rotating forward in the forward direction W1, the locked portion 107c separates from the locking portion 106d. Then, the end tooth 107g comes into contact with the tooth 109e of the driving gear 109. When the end tooth 107g comes into contact with the tooth 109e, the teeth 107e including the end tooth 107g are bent in the direction D2 approaching the rotation center RC1 by the notch portion 107f. Then, the end tooth 107g and the tooth 109e mesh with each other. That is, the delay transmission mechanism 118 changes from a state in which the rotation of the driving gear 109 is transmitted to the second gear 107 via the first gear 108 and the friction clutch 117 to a state in which the rotation of the driving gear 109 is directly transmitted to the second gear 107. Since the first rotating body 106 does not rotate, the end tooth 106g does not approach the drive gear 109. In other words, the end tooth 107g of the second gear 107 moves away from the end tooth 106g of the first rotating body 106.

[0083] As shown in FIG. 21, when the second gear 107 further rotates in the forward direction W1 due to the driving gear 109 further rotating in the forward direction W1, the locked portion 107b is locked to the locking portion 106d. More specifically, when the second gear 107 shown in FIG. 19 rotates in the forward direction W1 by the same rotation angle as the oscillation angle Ψ shown in FIG. 17, the locked portion 107b is locked to the locking portion 106d. At this time, the state of the first rotating body 106 and the second gear 107 is the state shown in FIG. 17. Therefore, the first rotating body 106 is pulled by the second gear 107 and rotates in the forward direction W1 together with the second gear 107, so that the end tooth 106g shown in FIG. 16 approaches the driving gear 109. Then, the end tooth 106g comes into contact with the tooth 109e of the driving gear 109. When the end tooth 106g and the tooth 109e come into contact with each other, the teeth 106e including the end tooth 106g are bent in a direction D2 toward the rotation center RC1 by the notch 106f. Then, the end tooth 106g and the tooth 109e mesh with each other. That is, the rotation of the drive gear 109 is directly transmitted to the first rotor 106.

[0084] 22, when the drive gear 109 further rotates in the forward rotation direction W1, the second gear 107 further rotates in the forward rotation direction W1, and the first rotating body 106 rotates forward in the forward rotation direction W1. The rotation of the second gear 107 is delayed by a rotation angle equal to the oscillation angle Ψ and transmitted to the first rotating body 106. Therefore, the rotation angle of the first rotating body 106 when the delay transmission mechanism 118 operates is smaller than the rotation angle of the second gear 107 by the rotation angle equal to the oscillation angle Ψ.

[0085] In the range in which the teeth 106e of the tooth row portion 106m shown in Figure 16 mesh with the teeth 109e of the drive gear 109, the rotation of the drive gear 109 is directly transmitted to the first rotating body 106, and the first rotating body 106 can be rotated in the forward rotation direction W1.

[0086] 22, when the drive gear 109 rotates in the reverse direction W2 with the tooth 109e meshing with the tooth 106e, the first rotor 106, the second gear 107, and the first gear 108 rotate in the reverse direction W2 by the delay transmission mechanism 118. When the drive gear 109 rotates in the reverse direction W2 to an angle where the end tooth 106g does not mesh with the tooth 109e, the first rotor 10 6 stops rotating, and the second gear 107 and the first gear 108 rotate in the reverse direction W2, causing the locked portion 107b to separate from the locking portion 106d.

[0087] 23, when the driving gear 109 further rotates in the reverse direction W2, the second gear 107 further rotates in the reverse direction W2, and the locked portion 107c is locked by the locking portion 106d. Then, the first rotating body 106 is pulled by the second gear 107, and the first rotating body 106 rotates in the reverse direction W2 together with the second gear 107.

[0088] As shown in FIG. 24, when the driving gear 109 rotates in the reverse direction W2 to an angle where the end tooth 107g does not mesh with the tooth 109e, the rotation of the driving gear 109 is not directly transmitted to the second gear 107. Since the second gear 107 pulls the first rotating body 106, a load torque for rotating the first rotating body 106 is generated on the second gear 107. The transmission torque of the friction clutch 117 is set so that the transmission torque of the friction clutch 117 is smaller than the load torque for rotating the first rotating body 106. Therefore, the friction clutch 117 slips, and the rotation of the first gear 108 is not transmitted to the second gear 107 via the friction clutch 117. In other words, the delay transmission mechanism 118 rotates only the driving gear 109 in the reverse direction W2 while the first rotating body 106 is held in the rotation position shown in FIG. 24. In other words, when the first rotating body 106 is rotated in the reverse direction W2 so that the end tooth 106g moves out of the position where it meshes with the tooth 109e, only the drive gear 109 can be rotated in the reverse direction W2 while the rotational position of the first rotating body 106 at that time is maintained.

[0089] In this state, the drive gear 109 is rotated forward in a forward direction W1, whereby the rotation of the drive gear 109 is transmitted to the second gear 107 via the first gear 108 and the friction clutch 117. Then, the drive gear 109 and the second gear 107 mesh with each other, whereby the rotation of the drive gear 109 is directly transmitted to the second gear 107. Then, the second gear 107 meshed with the drive gear 109 pulls the first rotating body 106 to rotate the first rotating body 106 forward in the forward direction W1, in a state where the first rotating body 106 is delayed by a rotation angle equal to the oscillation angle Ψ. Then, the drive gear 109 and the first rotating body 106 mesh with each other, whereby the rotation of the drive gear 109 is directly transmitted to the first rotating body 106. In other words, by reversing only the drive gear 109 in the reverse direction W2 at a position where the end tooth 106g is no longer meshing with the tooth 109e, and then rotating the drive gear 109 forward in the forward direction W1, the first rotating body 106 can be rotated forward in the forward direction W1 by a predetermined rotation angle.

[0090] Similarly, when the first rotating body 106 is rotated in the forward direction W1 and the end tooth 106i is displaced from the position where it meshes with the tooth 109e, only the drive gear 109 can be rotated in the forward direction W1 while maintaining the rotational position of the first rotating body 106 at that time. Moreover, after only the drive gear 109 is rotated in the forward direction W1 at a position where the end tooth 106i is displaced from the position where it meshes with the tooth 109e, the drive gear 109 can be reversed in the reverse direction W2 by a predetermined rotation angle.

[0091] In addition, when a switching operation or a return to origin operation is performed including a range in which the rotation of the second gear 107 is delayed and transmitted to the first rotating body 106 as in this embodiment, the rotation angle of the switching operation or the return to origin operation including the rotation angle that is delayed is set by the oscillation angle Ψ.

[0092] <Flow path switching operation> As shown in Fig. 25, the drive gear 109 is stopped in a state where the second engaging portion 109a is engaged with the engaged portion 110a in the reverse direction W2, or in a state where the second engaging portion 109a is slightly separated from the engaged portion 110a in the forward direction W1. Fig. 25 shows that in the flow path switching mechanism 44, the drive gear 109 is reversed in the reverse direction W2 in the state shown in Fig. 24, and then the origin return operation is performed, and in the second operation of the origin return operation, the engaging portion 105c is engaged with the convex portion 103b. In this state, the flow path switching operation and the pump suction operation start.

[0093] Bearing portion 110b has ends 110c and 110d. The position of roller 111 as shown in FIG. 25 when shaft 111a abuts against end 110c is pressing position P1 where it presses tube 112. Also, the position of roller 111 when shaft 111a abuts against end 110d is release position P2 where it releases the pressure on tube 112. Bearing portion 110b is shaped so that roller 111 presses tube 112 when roller 111 is at pressing position P1, and releases the pressure on tube 112 when roller 111 is at release position P2.

[0094] In the state of FIG. 25, the roller 111 may be located at the pressing position P1 or at the release position P2. In addition, in the state of FIG. 25, the rotational position of the roller 111 with respect to the rotation center RC1 may be any position. Furthermore, in the state of FIG. 25, the rotational position of the engaged portion 110a may be any position. That is, the rotational position of the driving gear 109 may be any position. In the pump 45, it is sufficient that the driving gear 109 is stopped in a state where the second engaging portion 109a is engaged with the engaged portion 110a in the reverse direction W2, or in a state where the second engaging portion 109a is slightly separated from the engaged portion 110a in the forward direction W1.

[0095] As shown in FIG. 26, the flow path switching mechanism 44 includes a switching mechanism 120 that receives a driving force via a drive gear 109 and can switch a flow path that communicates with the pump 45 among the multiple flow paths. The flow path switching mechanism 44 switches the flow path by making the switching mechanism 120 perform the switching operation described above. When the drive gear 109 rotates in the forward direction W1, the first rotor 106 located at the position shown in FIG. 25 rotates in the forward direction W1. At this time, the switching operation is performed including a range in which the rotation of the second gear 107 is delayed and transmitted to the first rotor 106, so that a rotation angle including the rotation angle delayed by the oscillation angle Ψ is set. For example, when the flow path switching angle is 90 degrees and the oscillation angle Ψ is 24 degrees, the first gear 108 is rotated 114 degrees, and the second rotor 103 rotates 90 degrees together with the first rotor 106. This allows the flow path communicating with the pump 45 to be switched between the multiple flow paths 101c and 101d.

[0096] 26, the forward direction W1, which is the rotation direction of the drive gear 109, is the direction in which the second engagement portion 109a moves away from the engaged portion 110a. Therefore, the pump drive shaft 110 does not rotate, and the suction operation by the pump 45 is not performed.

[0097] As shown in Fig. 27, when the drive gear 109 rotates in the reverse direction W2, the first rotating body 106 also rotates in the reverse direction W2. Even during reverse rotation, the switching operation is performed including the range in which the rotation of the second gear 107 is delayed and transmitted to the first rotating body 106, so the rotation angle including the delayed rotation angle is set by the oscillation angle Ψ. By performing forward and reverse rotation operations, the switching mechanism 120 rotates the second rotating body 103 to a predetermined rotation position and changes from the state shown in Figs. 25 and 26 in which the engaging portion 105c engages with the convex portion 103b to the state shown in Fig. 27 in which the engaging portion 105c engages with the convex portion 103c.

[0098] 27, the reverse direction W2, which is the rotation direction of the drive gear 109, is the direction in which the second engagement portion 109a approaches the engaged portion 110a, but since the rotation angle in the reverse rotation of the switching operation is the same as the rotation angle in the forward rotation, the second engagement portion 109a returns to the position before the forward rotation. In other words, since the pump drive shaft 110 does not rotate, the suction operation by the pump 45 is not performed even during the reverse rotation. In other words, the drive gear 109 as a drive rotor rotates forward and reverse in the area where the second engagement portion 109a does not engage with the engaged portion 110a, the flow path that communicates with the first flow path 101b is switched.

[0099] <About the pump suction operation> As shown in FIG. 28, the flow path switching mechanism 44 executes the pump suction operation. The pump suction operation is started in the state shown in FIG. 25. As shown in FIG. 28, the teeth 106e of the first rotor 106 are out of mesh with the teeth 109e of the drive gear 109. Therefore, when the drive gear 109 rotates in the reverse direction W2, the friction clutch 117 slips, and only the drive gear 109 rotates in the reverse direction W2. That is, while the pump 45 is driven, the drive gear 109 as the drive rotor and the first rotor 106 are disconnected. In order to ensure this connection and disconnection, the first rotor 106 may be provided with a stopper that limits unnecessary reverse rotation. For example, a protrusion is provided on the first rotor 106, and when the first rotor 106 is about to rotate in the reverse direction beyond the rotation position of FIG. 28, the first rotor 106 can be stopped reliably by making the protrusion hit the protrusion provided on the housing 101.

[0100] As shown in FIG. 28, in a state where the second engaging portion 109a is engaged with the engaged portion 110a, the driving gear 109 rotates in the reverse direction W2, and the pump driving shaft 110 rotates in the reverse direction W2 together with the driving gear 109. Since the pump driving shaft 110 rotates with the roller 111 positioned at the pressing position P1, the roller 111 rotates itself while pressing the tube 112, and revolves around the rotation center RC2 along the tube 112. Also, in the state shown in FIG. 25, when the roller 111 is positioned at the release position P2, the roller 111 receives a restoring force that tries to return the tube 112 to its original shape, and the roller 111 moves to the pressing position P1 together with the rotation of the pump driving shaft 110. At this time, the liquid in the tube 112 on the reverse direction W2 side with respect to the pressing position P1 of the roller 111 is pressurized, and a negative pressure acts on the liquid in the tube 112 on the forward direction W1 side with respect to the pressing position P1 of the roller 111. That is, the suction device 97 uses the pump 45 as a negative pressure source to apply negative pressure to the first flow path 101b connected to the discharge and recovery flow path , thereby suctioning the liquid in the tube 112.

[0101] <Pump release operation> As shown in Fig. 29, the flow path switching mechanism 44 executes a pump release operation. After the pump suction operation ends in the state shown in Fig. 28, the pump release operation starts. As shown in Fig. 29, the drive gear 109 rotates in the forward direction W1, so that the first rotor 106 rotates in the forward direction W1 to a rotation position where the end tooth 106i shown in Fig. 16 does not mesh with the tooth 109e.

[0102] The forward direction W1, which is the rotation direction of the drive gear 109, is the direction in which the second engagement portion 109a moves away from the engaged portion 110a, but as the drive gear 109 rotates forward in the forward direction W1, the second engagement portion 109a engages with the engaged portion 110a in the forward direction W1.

[0103] 30, even after the first rotating body 106 rotates in the forward direction W1 to an angle where the end tooth 107i does not mesh with the tooth 109e, the drive gear 109 continues to rotate in the forward direction W1. Because the tooth 106e of the first rotating body 106 is no longer in a position where it meshes with the tooth 109e of the drive gear 109, when the drive gear 109 rotates in the forward direction W1, the friction clutch 117 slips, and only the drive gear 109 rotates in the forward direction W1.

[0104] With the second engaging portion 109a engaged with the engaged portion 110a, the driving gear 109 rotates in the forward direction W1, and the pump driving shaft 110 rotates in the forward direction W1 together with the driving gear 109. As the tube 112 receives a restoring force that tries to return to its original shape, the roller 111 moves to the release position P2, and while rotating itself, the roller 111 revolves around the rotation center RC2 along the tube 112 with the pressure on the tube 112 released. In other words, the pump 45 is released.

[0105] As shown in FIG. 31, the drive gear 109 rotates in the reverse direction W2, so that the first rotating body 106 located at the position shown in FIG. 30 rotates in the reverse direction W2. More specifically, the rotation of the drive gear 109 is transmitted to the second gear 107 via the first gear 108 and the friction clutch 117. Then, the drive gear 109 and the second gear 107 mesh with each other, so that the rotation of the drive gear 109 is directly transmitted to the second gear 107. Then, the second gear 107 meshed with the drive gear 109 pulls the first rotating body 106 to reverse the first rotating body 106 in the reverse direction W2 in a state where the first rotating body 106 is delayed by the same rotation angle as the oscillation angle Ψ. Then, the drive gear 109 and the first rotating body 106 mesh with each other, so that the rotation of the drive gear 109 is directly transmitted to the first rotating body 106. Then, the first rotating body 106 is reversed in the reverse direction W2 to a predetermined rotation position shown in FIG. 31. In this manner, in the state shown in FIG. 30, the drive gear 109 rotates in the reverse direction W2 at a predetermined rotation angle, so that the first rotor 106 can be rotated to the rotation position shown in FIG.

[0106] The reverse direction W2, which is the rotation direction of the drive gear 109, is the direction in which the second engagement portion 109a moves away from the engaged portion 110a. Therefore, the pump drive shaft 110 does not rotate, and the suction operation by the pump 45 is not performed. The rotation angle is set so that the drive gear 109 stops in a state in which the second engagement portion 109a engages with the engaged portion 110a in the reverse direction W2, or in a state in which the second engagement portion 109a moves slightly away from the engaged portion 110a. In addition, since the rotation of the second gear 107 is delayed and transmitted to the first rotor 106, the rotation angle is set including the rotation angle delayed by the oscillation angle Ψ.

[0107] In addition, in the pump release operation, when the first rotor 106 rotates in the forward direction W1 to the rotation position shown in Fig. 29, the second rotor 103 also rotates in the forward direction W1, and the rotation position of the rotary valve 102 is also switched. Then, when the first rotor 106 rotates in the reverse direction W2 to the rotation position shown in Fig. 31, the engagement portion 105c moves along the outer periphery 103e of the second rotor 103, so that the second rotor 103 does not rotate. As a result, the rotation position of the rotary valve 102 that rotates together with the second rotor 103 becomes unknown. Therefore, after the pump release operation is performed, a home return operation is performed.

[0108] <Operation of the embodiment> The operation of this embodiment will be described. When the power supply of the multifunction device 11 is turned on, a pump release operation is performed first. In the flow path switching mechanism 44, the drive unit 119 continues to rotate the drive gear 109 in the forward rotation direction W1. As the first rotor 106 continues to rotate in the forward rotation direction W1, the first rotor 106 rotates in the forward rotation direction W1 to the rotation position shown in Fig. 30 and stops rotating at that position, and only the drive gear 109 continues to rotate in the forward rotation direction W1. As the drive gear 109 continues to rotate in the forward rotation direction W1, the roller 111 moves to the release position P2.

[0109] When the first rotating body 106 is in the rotation position shown in FIG. 30, the driving gear 109 rotates in the reverse direction W2 at a predetermined rotation angle, so that the first rotating body 106 can be rotated to the rotation position shown in FIG. 25. The reverse direction W2, which is the rotation direction of the driving gear 109, is the direction in which the second engaging portion 109a moves away from the engaged portion 110a, so the pump driving shaft 110 does not rotate. Therefore, the roller 111 continues to be located at the release position P2. Then, the driving gear 109 stops in a state in which the second engaging portion 109a engages with the engaged portion 110a in the reverse direction W2, or in a state shown in FIG. 25 in which the second engaging portion 109a is slightly away from the engaged portion 110a.

[0110] 25, the flow path switching mechanism 44 performs an origin return operation. More specifically, the flow path switching mechanism 44 performs a first operation in which the engaging portion 105c is disposed within the first interval S1, and a second operation in which the engaging portion 105c is disposed within the first interval S1. A second operation is performed in which the second rotating body 103 is positioned at a predetermined rotational position.

[0111] In the first operation, the driving source 114 rotates the second rotating body 103 by repeatedly rotating forward and backward at a rotation angle smaller than the first angle θ1 and equal to or greater than the second angle θ2 until the engagement portion 105c is positioned within the first interval S1.

[0112] The rotation angle in the first operation is smaller than the first angle θ1. Therefore, when the engaging portion 105c is disposed within the first interval S1, no matter how many times the first operation is performed, the engaging portion 105c does not move out of the first interval S1 and remains disposed within the first interval S1.

[0113] The rotation angle in the first operation is equal to or larger than the second angle θ2. Therefore, when the engaging portion 105c is disposed within the second interval S2 as another interval, when the first operation is performed once, the engaging portion 105c moves out of the second interval S2 and is disposed within any interval on the reverse direction W2 side of the second interval S2.

[0114] When the interval at which the engaging portion 105c is arranged is the first interval S1, no matter how many times the first operation is performed thereafter, the engaging portion 105c does not move out of the first interval S1, and the engaging portion 105c is arranged within the first interval S1.

[0115] When the interval at which the engaging portion 105c is arranged is the second interval S2, in the next first operation, the engaging portion 105c moves out from within the second interval S2 and is arranged within any interval on the reverse direction W2 side of the second interval S2.

[0116] The driving source 114 repeatedly executes the first operation. More specifically, the driving source 114 causes the first rotor 106 to execute the first operation a number of repetitions that is at least one less than the number of protrusions provided on the outer periphery 103e. This allows the engagement portion 105c to be positioned within the first interval S1. The number of repetitions refers to the number of times the first operation is executed, which is an example of a forward / reverse operation in which forward rotation and reverse rotation are performed once each.

[0117] The first operation is a forward / reverse operation in the direction in which the second engaging portion 109a moves away from the engaged portion 110a, so that the pump drive shaft 110 does not rotate. Therefore, the roller 111 remains at the release position P2 even during the first operation.

[0118] When the engagement portion 105c is positioned within the first interval S1, in the second operation, the driving source 114 switches the rotational position of the second rotating body 103 to a predetermined rotational position by causing the first rotating body 106 to perform forward and reverse rotation at a predetermined rotational angle greater than or equal to the first angle θ1.

[0119] The rotation angle in the second operation is equal to or larger than the first angle θ1. Therefore, during forward rotation, the engagement portion 105c presses the convex portion 103d on the forward rotation direction W1 side among the convex portions 103d, 103b that form the first interval S1, thereby moving the second rotor 103. The rotation angle is set to a rotation angle that rotates the second rotor 103 to a predetermined rotation position, so that the second rotor 103 can be moved to a targeted position by a single forward / reverse operation. This allows the first flow path 101b to communicate with a predetermined flow path different from the first flow path 101b.

[0120] Since the rotation angle in the second operation is equal to or larger than the first angle θ1, when the second operation is performed once, the engaging portion 105c moves out of the first interval S1 and is disposed within any interval on the reverse direction W2 side of the first interval S1. The rotation angle in the second operation is set to a rotation angle that rotates the second rotor 103 to a predetermined rotation position and engages the engaging portion 105c with a predetermined protrusion.

[0121] Like the first operation, the second operation is a forward / reverse operation in the direction in which the second engaging portion 109a moves away from the engaged portion 110a, so that the pump drive shaft 110 does not rotate. Therefore, the roller 111 remains at the release position P2 even during the second operation.

[0122] With this state as the origin of the rotary valve 102, the pump drive shaft 110 does not rotate in the subsequent switching operation because the second engaging portion 109a rotates in the direction away from the engaged portion 110a. Therefore, the roller 111 remains in the release position P2 during the subsequent switching operation.

[0123] When negative pressure from the pump 45 is introduced into the storage chamber 51 in the liquid storage section 50 via the bubble discharge mechanism BS, the flow path switching mechanism 44 communicates the first flow path 101b and the second flow path 101c by the origin return operation, thereby communicating the pump 45 with the branch flow path 96. Then, when the second operation of the origin return operation is completed, the flow path switching mechanism 44 reverses the drive gear 109 in the reverse direction W2. Then, the friction clutch 117 slips, and only the drive gear 109 reverses in the reverse direction W2 while the first rotor 106 remains stopped. Then, the pump suction operation is performed.

[0124] With the second engaging portion 109a engaged with the engaged portion 110a, the driving gear 109 rotates in the reverse direction W2, and the pump driving shaft 110 rotates in the reverse direction W2 together with the driving gear 109. The pump driving shaft 110 rotates with the roller 111 moved to the pressing position P1 by the restoring force of the tube 112. The tube 112 is pressurized, and negative pressure acts on the liquid in the tube 112 on the reverse direction W2 side with respect to the pressing position P1 of the roller 111, thereby sucking in the liquid in the branch flow path 96 communicating with the inside of the tube 112. That is, the liquid containing bubbles in the bubble discharge mechanism BS is sent to the waste liquid storage section 47 through the discharge and recovery flow path 46 connected to the pump 45.

[0125] When negative pressure from the pump 45 is introduced into the closed space formed between the cap 41 and the nozzle surface 30a, the flow path switching mechanism 44 communicates the first flow path 101b and the third flow path 101d by an origin return operation, thereby communicating the pump 45 with the discharge flow path 42. The pump 45 is driven with the liquid discharger 30 capped. Negative pressure acts on the liquid in the tube 112, thereby sucking in the liquid in the discharge flow path 42 that communicates with the inside of the tube 112. That is, the liquid discharged or discharged from the nozzle 31 of the liquid discharger 30 is sent to the waste liquid storage unit 47 through the discharge recovery flow path 46 connected to the pump 45.

[0126] When the pump suction operation is completed, a pump release operation is performed. In the pump release operation, when the first rotor 106 rotates in the forward direction W1 to the rotation position shown in FIG. 29, the second rotor 103 also rotates in the forward direction W1, so that the rotation position of the rotary valve 102 is also switched. Then, when the first rotor 106 rotates in the reverse direction W2 to the rotation position shown in FIG. 31, the engagement portion 105c moves along the outer periphery 103e of the second rotor 103, so that the second rotor 103 does not rotate. As a result, the rotation position of the rotary valve 102 that rotates together with the second rotor 103 becomes unknown, so that after the pump release operation, a home position return operation is performed.

[0127] Even if the flow path switching mechanism 44 stops midway through its operation due to an unexpected error occurring in the liquid discharger 12, the pump release operation can be performed to return the flow path switching mechanism 44 to a state in which the pump 45 is released. Also, the origin return operation can be performed to return the flow path switching mechanism 44 to a state in which the second rotor 103, which rotates together with the rotary valve 102, is located at a predetermined rotational position.

[0128] <Effects of the embodiment> The effects of this embodiment will be described. The switching mechanism 120, the flow path switching mechanism 44, and the liquid ejection device 12 of this embodiment provide the following advantages.

[0129] (1) The driving source 114 causes the first rotor 106 to repeatedly perform forward and reverse rotations at a rotation angle smaller than the first angle θ1 and equal to or larger than the second angle θ2, thereby positioning the engagement portion 105c within the first interval S1. The central angle formed by the two convex portions 103b and 103d constituting the first interval S1 with respect to the rotation center RC1 is the first angle θ1, and the central angle formed by the two convex portions constituting the second interval S2 with respect to the rotation center RC1 is the second angle θ2. The rotation angle in the forward and reverse rotations is smaller than the first angle θ1. Therefore, when the engagement portion 105c is disposed within the first interval S1, no matter how many times the forward and reverse rotations are performed, the engagement portion 105c does not move out of the first interval S1, and the engagement portion 105c is disposed within the first interval S1. In addition, the rotation angle in the forward and reverse rotations is equal to or larger than the second angle θ2. Therefore, when the engaging portion 105c is located within the second interval S2, the engaging portion 105c is located within one of the intervals on the reverse direction W2 side by the forward / reverse rotation operation. Then, the engaging portion 105c is located within the first interval S1 by the forward / reverse rotation operation that is repeatedly performed. In other words, even if the rotational position of the second rotating body 103 becomes unknown due to an unintended event, the second rotating body 103 can be located within the first interval S1 by the first rotating body 106 repeatedly performing the forward / reverse rotation operation at that rotation angle without having a position detector.

[0130] (2) The driving source 114 causes the first rotating body 106 to repeatedly perform forward and reverse rotations at a number of repetitions that is one less than the number of convex portions provided on the outer periphery 103e. When the engaging portion 105c is located within the second interval S2, the forward and reverse rotations cause the engaging portion 105c to be located within any interval on the reverse direction W2 side. When the engaging portion 105c is located within another interval farthest from the first interval S1 located on the reverse direction W2 side, the number of repetitions for the engaging portion 105c to be located within the first interval S1 becomes the largest. Even in such a case, when the first rotating body 106 performs forward and reverse rotations at a number of repetitions that is one less than the number of convex portions provided on the outer periphery 103e of the second rotating body 103, the engaging portion 105c is located within the first interval S1. In other words, by causing the first rotating body 106 to repeatedly perform forward and reverse rotation a number of times that is at least one less than the number of protrusions provided on the outer periphery 103e of the second rotating body 103, the second rotating body 103 can be positioned within the first interval S1.

[0131] (3) When the engaging portion 105c is located within the first interval S1, the driving source 114 causes the first rotating body 106 to perform forward and reverse rotation at a predetermined rotation angle equal to or greater than the first angle θ1. Since the rotation angle is equal to or greater than the first angle θ1, during forward rotation, the engaging portion 105c presses the convex portion 103d on the forward rotation direction W1 side among the convex portions 103d and 103b that form the first interval S1, thereby moving the second rotating body 103. Since the rotation angle is set to a rotation angle that rotates the second rotating body 103 to a predetermined rotation position, the second rotating body 103 can be rotated to a desired rotation position with one forward and reverse operation. In other words, the switching time can be shortened.

[0132] (4) The first rotating body 106 has the first biasing member 104 that biases the engaging portion 105c toward the outer periphery 103e of the second rotating body 103, thereby preventing the engaging portion 105c from coming off the outer periphery 103e of the second rotating body 103.

[0133] (5) In the switching mechanism 120, the engaging portion 105c engages with a predetermined convex portion of the second rotor 103 during normal rotation and presses the predetermined convex portion, thereby rotating the second rotor 103 to a desired rotational position. This allows the multiple convex portions 103b, 103c, and 103d of the second rotor 103 to be positioned at predetermined positions. At this time, the rotary valve 102 that rotates together with the second rotor 103 is positioned at a predetermined rotational position, so that the first flow path 101b and the first flow path 101c are connected to each other. The first flow path 101b communicates with one of two or more flow paths 101c and 101d that are different from the first flow path 101b. That is, the switching mechanism 120 can switch the flow path that communicates with the first flow path 101b.

[0134] (6) The first rotor 106 receives the driving force transmitted from the driving source 114 via the driving gear 109, so that the pump drive and the flow path switching can be performed by the driving force from the single driving source 114. In other words, the configuration of the device can be simplified.

[0135] (7) The pump 45 is driven by the rotation of the drive gear 109 with the second engaging portion 109a engaged with the engaged portion 110a. While the pump 45 is driven, the drive gear 109 is disconnected from the first rotor 106, and the flow path switching mechanism 44 is in a state in which it cannot switch the flow path. Therefore, it is possible to prevent the flow path from being switched while the pump 45 is driven.

[0136] (8) The flow path communicating with the first flow path 101b is switched by the driving gear 109 rotating forward and backward in a region where the second engaging portion 109a is not engaged with the engaged portion 110a. That is, the flow path can be switched in a rotation range of the driving gear 109 where the pump 45 is not driven. Therefore, it is possible to prevent the pump 45 from being driven while the flow path is being switched.

[0137] (9) In the liquid ejection device 12, the flow path switching mechanism 44 is connected to a branch flow path 96 connected midway through the supply flow path 27 that supplies liquid to the liquid ejection unit 30, and to a discharge flow path 42 connected to a cap 41 capable of forming a closed space in which the nozzle 31 opens. This makes it possible to switch the liquid ejection device 12 between a state in which the pump 45 sucks liquid from the nozzle 31 through the discharge flow path 42, a state in which the pump 45 sucks liquid from the supply flow path 27, and a state in which the pump 45 is released.

[0138] Second embodiment The second embodiment will be described below with reference to the drawings. Since the second embodiment is substantially the same as the first embodiment, the same components are denoted by the same reference numerals and the duplicated description will be omitted.

[0139] 32, the switching mechanism 120 includes a second rotor 103 that rotates around a rotation center RC1 of the first rotor 106 and has a plurality of protrusions provided on an outer periphery 103e at intervals in the rotation direction. In this embodiment, five protrusions 103b, 103c, 103d, 103h, and 103i are provided on the outer periphery 103e of the second rotor 103 at a second interval S2 in the rotation direction.

[0140] The first rotating body 106 includes an engaging member 105. The engaging member 105 has an engaging portion 105c. The engaging member 105 is guided by the first rotating body 106 and configured to be slidable in a direction D1 in which the engaging portion 105c moves away from the rotation center RC1 and in a direction D2 in which the engaging portion 105c moves toward the rotation center RC1. The first rotating body 106 includes a first biasing member 104 that biases the engaging portion 105c toward the outer periphery 103e of the second rotating body 103.

[0141] In this embodiment, the second angle θ2 is formed at an angle different from the central angle formed by the first flow path 101b and a flow path other than the first flow path 101b with respect to the rotation center RC1. When the first rotor 106 rotates in the forward rotation direction W1 in the second operation, for example, the rotary valve 102 rotates forward together with the second rotor 103 with the engagement portion 105c engaged with the convex portion 103i of the second rotor 103. When the convex portion 103i is located at a predetermined position due to the forward rotation, the second rotor 103 rotates at a rotation angle that rotates the rotary valve 102 together with the second rotor 103 to a predetermined rotation position. The rotation angle in the operation is set. As a result, the flow path switching mechanism 44 communicates the first flow path 101b with a predetermined flow path. Note that the origin return operation may be performed again from that state, so that the flow path switching mechanism 44 communicates the first flow path 101b with another flow path in the second operation of the origin return operation.

[0142] The rotary valve 102 may have five flow paths including the first flow path, and five convex portions 103b, 103c, 103d, 103h, and 103i may be provided at positions corresponding to the switching positions of the rotary valve 102. The rotary valve 102 is configured such that, when the rotary valve 102 rotates together with the second rotor 103 to a predetermined rotational position, the outer circumferential surface 102a blocks flow paths other than the flow path communicating with the first flow path 101b, thereby making it possible to communicate the first flow path 101b with the predetermined flow path.

[0143] <Actions and Effects of the Embodiment> The actions and effects of the second embodiment are the same as those of the first embodiment, and therefore a description thereof will be omitted. <Modifications of the embodiment> This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other to the extent that there is no technical contradiction.

[0144] The number of the multiple protrusions of the second rotating body 103 is not limited. It is sufficient that the multiple protrusions of the second rotating body 103 form the first interval S1 and another interval smaller than the first interval S1. At least two or more protrusions are required.

[0145] There may be multiple first intervals S1. In that case, the driving source 114 causes the first rotor 106 to repeatedly perform forward and reverse rotation in the first operation a number of repetitions that is at least one less than the number of convex portions that are provided most frequently in succession in the second interval S2 as another interval on the outer periphery 103e. This allows the engaging portion 105c to be positioned within the first interval S1.

[0146] There may be a third interval smaller than the second interval S2. Even when there is a third interval, the second rotor 103 may have a convex portion so that the first flow path 101b communicates with one of two or more flow paths different from the first flow path 101b when the multiple convex portions of the second rotor 103 are located at a predetermined position. In addition, since the third interval is smaller than the second interval S2, the central angle formed by the two convex portions constituting the second interval S2 with respect to the rotation center RC1 is larger than the central angle formed by the two convex portions constituting the third interval with respect to the rotation center RC1. Therefore, even when there is a third interval smaller than the second interval S2, the central angle formed by the two convex portions constituting the second interval S2, which is the largest interval among the other intervals, with respect to the rotation center RC1 is the second angle θ2.

[0147] The first rotating body 106 may not have the teeth 106e. In this embodiment, in a state where the second gear 107, which is already meshed with the driving gear 109, pulls the first rotating body 106, the teeth 106e of the first rotating body 106 and the teeth 108e of the driving gear 109 mesh with each other, so that the driving gear 109 rotates the first rotating body 106. However, since the first rotating body 106 is already rotating as a result of the second gear 107 pulling the first rotating body 106, the first rotating body 106 may continue to rotate with the second gear 107 pulling the first rotating body 106. In other words, the teeth 106e of the first rotating body 106 may not be present.

[0148] <Technical ideas and effects understood from the embodiments and modified examples> The technical ideas and effects obtained from the above-described embodiment and modified examples will be described below.

[0149] (A) The switching mechanism includes a first rotor that receives a driving force from a driving source and rotates in a forward or reverse direction, and a rotor that rotates around the center of rotation of the first rotor and has a plurality of protrusions on its outer periphery that change the direction of rotation. and a second rotating body provided at an interval from the first rotating body, the first rotating body including an engaging portion displaceable along the outer periphery of the second rotating body, and when the first rotating body rotates in the forward direction, the engaging portion engages with the convex portion, thereby rotating the second rotating body in the forward direction together with the first rotating body, and when the first rotating body rotates in the reverse direction, the engaging portion moves along the outer periphery of the second rotating body to suppress the reverse rotation of the second rotating body, and the driving source causes the first rotating body to perform a forward / reverse operation in which the first rotating body rotates in the forward direction and in the reverse direction in turn, thereby suppressing the rotation of the second rotating body. a first interval among the intervals being formed to be larger than the other intervals, and when a central angle formed by two convex portions constituting the first interval with respect to the rotation center is defined as a first angle, and a maximum angle among central angles formed by two convex portions constituting the other intervals with respect to the rotation center is defined as a second angle, the driving source repeatedly performs the forward and reverse rotation operation of the first rotor at a rotation angle smaller than the first angle and equal to or larger than the second angle, thereby positioning the engagement portion within the first interval.

[0150] According to this configuration, the central angle formed by the two convex parts constituting the first interval with respect to the rotation center is the first angle, and the maximum angle of the central angles formed by the two convex parts constituting the other interval with respect to the rotation center is the second angle. The rotation angle in the forward and reverse rotation operation is smaller than the first angle and equal to or greater than the second angle. Since the rotation angle in the forward and reverse rotation operation is smaller than the first angle, when the engagement part is disposed within the first interval, the engagement part is disposed within the first interval, no matter how many times the forward and reverse rotation operation is performed. Furthermore, since the rotation angle in the forward and reverse rotation operation is equal to or greater than the second angle, when the engagement part is disposed within the other interval, the engagement part is disposed within one of the intervals on the reverse direction side by the forward and reverse rotation operation. Then, the engagement part is disposed within the first interval by the forward and reverse rotation operation that is repeatedly performed. In other words, even if the rotation position of the second rotating body becomes unknown due to an unintended event, the second rotating body can be disposed within the first interval by repeatedly performing the forward and reverse rotation operation at that rotation angle of the first rotating body without having a position detector.

[0151] (B) In the above switching mechanism, the driving source may position the engagement portion within the first interval by repeatedly executing the forward and reverse rotation operation of the first rotating body a number of repetitions that is at least one less than the number of the protrusions provided on the outer periphery.

[0152] According to this configuration, when the engagement portion is disposed within another interval, the forward / reverse rotation operation disposes the engagement portion within one of the intervals on the reverse direction side. When the engagement portion is disposed within another interval farthest from the first interval located on the reverse direction side, the number of repetitions for disposing the engagement portion within the first interval is the greatest. Even in such a case, when the first rotating body executes the forward / reverse rotation operation with a number of repetitions that is one less than the number of convex portions provided on the outer periphery of the second rotating body, the engagement portion is disposed within the first interval. In other words, the second rotating body can be disposed within the first interval by repeatedly executing the forward / reverse rotation operation of the first rotating body with a number of repetitions that is one less than the number of convex portions provided on the outer periphery of the second rotating body or more.

[0153] (C) In the above switching mechanism, when the engagement portion is positioned within the first interval, the driving source may switch the rotational position of the second rotating body to a predetermined rotational position by causing the first rotating body to perform the forward / reverse operation at a predetermined rotational angle that is greater than or equal to the first angle.

[0154] According to this configuration, the rotation angle in the forward / reverse rotation operation performed when the engaging portion is located within the first interval is equal to or greater than the first angle, so that during forward rotation, the engaging portion presses the protruding portion on the forward rotation side among the protruding portions that form the first interval, thereby moving the second rotating body. The rotation angle is set to a rotation angle that rotates the second rotating body to a predetermined rotation position, so that the second rotating body can be rotated to a targeted rotation position with a single forward / reverse rotation operation. In other words, the switching time can be shortened.

[0155] (D) In ​​the switching mechanism, the first rotating body may have a first biasing member that biases the engagement portion toward an outer periphery of the second rotating body. According to this configuration, it is possible to prevent the engaging portion from coming off the outer periphery of the second rotating body.

[0156] (E) A flow path switching mechanism includes the switching mechanism and a rotary valve having a first flow path and two or more flow paths different from the first flow path, and the rotary valve is capable of switching a flow path among the two or more different flow paths that communicates with the first flow path by rotating the rotary valve, wherein the rotary valve is rotatable together with the second rotor, and when a predetermined convex portion among the multiple convex portions of the second rotor is located at a predetermined position, the first flow path is connected to one of the two or more different flow paths.

[0157] According to this configuration, in the switching mechanism, the engagement portion engages with a predetermined convex portion of the second rotor during forward rotation and presses the predetermined convex portion, thereby rotating the second rotor to a targeted rotational position. This allows the multiple convex portions of the second rotor to be positioned at predetermined positions. At this time, the rotary valve that rotates together with the second rotor is positioned at a predetermined rotational position, so that the first flow path communicates with one of two or more flow paths different from the first flow path. In other words, the switching mechanism can switch the flow path that communicates with the first flow path.

[0158] Furthermore, by having the above-mentioned switching mechanism in the flow path switching mechanism, it is possible to obtain the same effects as those of the above-mentioned switching mechanisms (A) to (D). (F) The above flow path switching mechanism may include a pump having one end connected to the first flow path, and a drive rotor that receives the driving force transmitted from the drive source to drive the pump, and the first rotor may receive the driving force transmitted from the drive source via the drive rotor.

[0159] According to this configuration, the pump drive and the flow path switching can be performed by the driving force from a single driving source, which means that the configuration of the device can be simplified. (G) In the above flow path switching mechanism, the driving rotor has a second engaging portion, and the pump has an engaged portion that is engageable with the second engaging portion in a rotational direction, and the pump is driven by the driving rotor rotating with the second engaging portion engaged with the engaged portion, and the connection between the driving rotor and the first rotor may be disconnected while the pump is driven.

[0160] According to this configuration, since the drive rotor and the first rotor are disconnected while the pump is driven, the flow path switching mechanism is in a state where it cannot switch the flow path, and therefore it is possible to prevent the flow path from being switched while the pump is driven.

[0161] (H) In the above flow path switching mechanism, the flow path communicating with the first flow path may be switched by rotating the driving rotor in a forward and reverse direction in a region where the second engagement portion does not engage with the engaged portion.

[0162] According to this configuration, the flow path can be switched in a rotation range of the driving rotor in which the pump is not driven, and therefore, the pump can be prevented from being driven while the flow path is being switched.

[0163] (I) A liquid ejection device includes a liquid ejection section that ejects liquid from a nozzle, a supply flow path that supplies liquid from a liquid container that contains liquid to the liquid ejection section, a cap that can form a closed space in which the nozzle opens, a branch flow path having one end connected to the middle of the supply flow path, a discharge flow path having one end connected to the cap, a drive source, and the flow path switching mechanism, the pump is a suction pump, and the other end of the branch flow path is one of two or more flow paths different from the first flow path. The other end of the discharge flow path is connected to a second flow path among two or more flow paths different from the first flow path, and the other end of the discharge flow path is connected to a third flow path among two or more flow paths different from the first flow path.

[0164] According to this configuration, in the liquid ejection device, the flow path switching mechanism is connected to a branch flow path connected midway through the supply flow path that supplies liquid to the liquid ejection section, and to a discharge flow path connected to a cap that can form a closed space that the nozzle opens in. This makes it possible to switch the liquid ejection device between a state in which the pump sucks liquid from the nozzle through the discharge flow path, a state in which the pump sucks liquid from the supply flow path, and a state in which the pump is released.

[0165] Furthermore, by providing the liquid ejection device with the above-mentioned flow path switching mechanism, it is possible to obtain the same effects as those of the above-mentioned flow path switching mechanisms (F) to (H). (J) A flow path switching mechanism includes a drive rotor that can rotate by receiving a driving force transmitted from a drive source, a pump that receives the driving force through the drive rotor, and a switching mechanism that receives the driving force through the drive rotor and can switch a flow path communicating with the pump among a plurality of flow paths, wherein the drive rotor has a second engaging portion, and the pump has an engaged portion that can engage with the second engaging portion in the rotation direction, and the flow path communicating with the pump is switched by the drive rotor rotating forward and reverse in a region where the second engaging portion does not engage with the engaged portion, and the pump is driven by the drive rotor rotating with the second engaging portion engaged with the engaged portion.

[0166] According to this configuration, while the pump is driven, the connection between the driving rotor and the first rotor is cut off, so that the flow path switching mechanism cannot switch the flow path. Also, the flow path can be switched in a rotation range of the driving rotor where the pump is not driven. Therefore, the pump can be prevented from being driven while the flow path is being switched, and the flow path can be prevented from being switched while the pump is driven. [Explanation of symbols]

[0167] 11...multifunction device, 12...liquid ejection device, 13...image reading device, 15...operation unit, 16...display unit, 17...operation panel, 18...liquid container, 19...holding unit, 20...casing, 26...liquid supply device, 27...supply flow path, 27a...first supply path, 27b...second supply path, 30...liquid ejection unit, 30a...nozzle surface, 31...nozzle, 33...carriage, 40...maintenance device, 41...cap, 42...discharge flow path, 42a...one end, 42b...other end, 43...tube, 44...flow path switching mechanism, 45...pump, 45a...one end, 45b...other end, 46...discharge Output / recovery flow path, 47...waste liquid storage section, 50...liquid storage section, 51...storage chamber, 96...branched flow path, 96a...one end, 96b...other end, 97...suction device, 100...control section, 101...housing, 101a...inner circumferential surface, 101b...first flow path, 101c...second flow path, 101d...third flow path, 102...rotary valve, 102a...outer circumferential surface, 102b...groove, 102c...groove end, 102d...groove end, 103...second rotor, 103a...inner circumferential surface, 103b...convex portion, 103c...convex portion, 103d...convex portion, 103e...outer circumferential surface, 103f...side surface, 103g...inclined surface, 103 h...protruding portion, 103i...protruding portion, 104...first biasing member, 104a...hooking portion, 104b...hooking portion, 105...engaging member, 105a...hole portion, 105b...hooked portion, 105c...engaging portion, 105f...side surface, 105g...slope, 106...first rotating body, 106a...inner peripheral surface, 106b...shaft portion, 106c...hooked portion, 106d...engaging portion, 106e...teeth, 106f...notch portion, 106g...end portion, 106h...notch portion, 106i...end portion, 106m...tooth row portion, 106n...toothless portion, 107...second gear, 107a...inner peripheral surface, 107b...hooked portion, 107 c...engaged portion, 107d...groove portion, 107e...tooth, 107f...notch portion, 107g...end portion, 107h...notch portion, 107i...end portion, 107m...tooth row portion, 107n...tooth-missing portion, 108...first gear, 108a inner peripheral surface, 108b...joint portion, 108c...joint portion, 108e...teeth, 109...driving gear as driving rotor, 109a...second engaging portion, 109e...teeth, 110...pump drive shaft, 110a...engaged portion, 110b...bearing portion, 110c...end portion, 110d...end portion, 111...roller, 111a...shaft, 111b...outer peripheral surface, 112...tube , 113...second biasing member, 114...driving source, 117...friction clutch, 118...delay transmission mechanism, 119...driving unit, 120...switching mechanism, θ1...first angle, θ2...second angle, Φ1...first rotation angle, Φ2...second rotation angle, Ψ...oscillation angle, BS...bubble discharge mechanism, D1...direction away from rotation center, D2...direction approaching rotation center, P1...pressing position, P2...release position, RC1...rotation center, RC2...rotation center, S1...first interval, S2...second interval as another interval, W1...forward rotation direction, W2...reverse direction, X...scanning direction, Y...conveyance direction, Z...vertical direction.

Claims

1. a first rotating body that rotates in a forward direction and a reverse direction by receiving a driving force transmitted from a driving source; a second rotating body that rotates around a rotation center of the first rotating body and has a plurality of protrusions provided at intervals in the rotation direction on an outer periphery thereof; the first rotating body includes an engaging portion displaceable along the outer periphery of the second rotating body, When the first rotating body rotates in the forward direction, the engaging portion engages with the convex portion, thereby causing the second rotating body to rotate in the forward direction together with the first rotating body, and when the first rotating body rotates in the reverse direction, the engaging portion moves along the outer periphery of the second rotating body to suppress the reverse rotation of the second rotating body, A switching mechanism that switches a rotation position of the second rotating body to a predetermined rotation position by causing the driving source to perform a forward / reverse operation in which the first rotating body rotates forward and backward in sequence, At least one of the intervals, a first interval, is formed to be larger than the other intervals, When a central angle formed by the two convex portions constituting the first interval with respect to the rotation center is defined as a first angle, and a maximum angle among central angles formed by the two convex portions constituting the other interval with respect to the rotation center is defined as a second angle, The switching mechanism is characterized in that the driving source repeatedly performs the forward and reverse rotation of the first rotating body at a rotation angle smaller than the first angle and equal to or greater than the second angle, thereby positioning the engagement portion within the first interval.

2. The switching mechanism according to claim 1, characterized in that the driving source positions the engagement portion within the first interval by repeatedly executing the forward and reverse rotation operation of the first rotating body a number of times that is at least one less than the number of the convex portions.

3. The switching mechanism according to claim 1 or claim 2, characterized in that when the engagement portion is positioned within the first interval, the driving source switches the rotational position of the second rotating body to a predetermined rotational position by causing the first rotating body to perform the forward / reverse operation at a predetermined rotational angle that is greater than or equal to the first angle.

4. 4. The switching mechanism according to claim 1, wherein the first rotating body has a first biasing member that biases the engaging portion toward an outer periphery of the second rotating body.

5. A switching mechanism according to any one of claims 1 to 4; a rotary valve having a first flow path and two or more flow paths different from the first flow path, the rotary valve being capable of switching a flow path that communicates with the first flow path among the two or more different flow paths by rotating the rotary valve; The rotary valve is rotatable together with the second rotor, and when a predetermined convex portion among the plurality of convex portions of the second rotor is located at a predetermined position, the first flow path is connected to any one of the two or more different flow paths.

6. a pump having one end communicating with the first flow path; a drive rotor that receives the driving force transmitted from the drive source and drives the pump, 6. The flow path switching mechanism according to claim 5, wherein the first rotor receives the driving force transmitted from the driving source via the driving rotor.

7. The driving rotor has a second engagement portion, the pump has an engaged portion engageable with the second engaging portion in a rotational direction, The pump is driven by the driving rotor rotating in a state in which the second engaging portion is engaged with the engaged portion, 7. The flow path switching mechanism according to claim 6, wherein the drive rotor and the first rotor are disconnected while the pump is driven.

8. The flow path switching mechanism according to claim 7, characterized in that the flow path communicating with the first flow path is switched by rotating the driving rotor in a forward and reverse direction in an area where the second engaging portion does not engage with the engaged portion.

9. a liquid ejection unit that ejects liquid from a nozzle; a supply flow path that supplies liquid from a liquid container that contains liquid to the liquid ejection unit; a cap capable of forming a closed space in which the nozzle opens; A branch flow path, one end of which is connected to the middle of the supply flow path; an exhaust flow path, one end of which is connected to the cap; A driving source; The flow path switching mechanism according to any one of claims 6 to 8, the pump is a suction pump; the other end of the branch flow path is connected to a second flow path among two or more flow paths different from the first flow path, The liquid ejection device according to claim 1, wherein the other end of the discharge flow path is connected to a third flow path among two or more flow paths different from the first flow path.

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