JP2019014545A - Sheet carrier device and image formation device - Google Patents

Abstract

To improve positioning accuracy of a changeover member.SOLUTION: A changeover mechanism 70 has: a changeover member 71 movable between a first position and a second position; a link arm 73 moving the changeover member 71 between the first position and the second position by acting the changeover member 71; and a solenoid 74 driving the link arm 73. In addition, the changeover mechanism 70 has an elastic member 81 to which the changeover member 71 moved by driving of the solenoid 74 abuts so as to position the changeover member 71 to the first position, and an elastic member 80 arranged between the changeover member 71 and the link arm 73 and deformed with pressing by the link arm 73 when moving the changeover member 71 to the first position.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a sheet conveying apparatus that conveys a sheet and an image forming apparatus including the sheet conveying apparatus.

  2. Description of the Related Art Conventionally, some image forming apparatuses such as copiers, printers, and facsimile machines that have a sheet conveying apparatus include a switching member that switches a sheet conveying path. The position of the switching member is generally determined by bringing a part of the switching member into contact with the abutting portion. However, when the conveyance path is switched in a short time as the sheet conveyance speed increases, the switching member The abutment sound at the time of abutting against the abutting part has become conspicuous. Therefore, Patent Document 1 proposes an image forming apparatus that suppresses contact noise by providing an elastic member at the abutting portion.

JP2013-245037A

  Patent Document 1 describes that the amount of collapse of the elastic member is adjusted by moving the abutment portion in order to suppress variation in the amount of collapse of the elastic member due to the dimensional tolerance of each member. However, in patent document 1, since the abutting part was moved, there existed a problem that the positioning accuracy of a switching member fell.

  Therefore, an object of the present invention is to improve the positioning accuracy of the switching member.

  The sheet conveying apparatus of the present invention includes a conveying unit that conveys a sheet, a first position that guides the sheet conveyed to the conveying unit to a first conveying path, and a sheet conveyed to the conveying unit to a second conveying path. A switching member that is movable between a second position that guides the switching member, a link member that acts on the switching member to move the switching member between the first position and the second position, and the switching Drive means for driving the link member so that the member moves to the first position, first positioning means for positioning the switching member at the first position, and disposed between the switching member and the link member And a deformation means that is deformed by being pressed by the link member when the switching member is moved to the first position.

  According to the present invention, the positioning accuracy of the switching member is improved.

1 is an explanatory diagram illustrating a schematic configuration of a printer as an example of an image forming apparatus according to a first embodiment. FIG. It is a perspective view of the switching mechanism in a 1st embodiment. (A), (b) and (c) is explanatory drawing which shows operation | movement of the switching member of the switching mechanism in 1st Embodiment. FIG. 9 is a perspective view of a printer switching mechanism that is an example of an image forming apparatus according to a second embodiment. It is an enlarged view of the area | region V shown in FIG. (A), (b) and (c) is explanatory drawing which shows operation | movement of the switching member of the switching mechanism in 2nd Embodiment.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.
[First Embodiment]
FIG. 1 is an explanatory diagram illustrating a schematic configuration of a printer 1 as an example of an image forming apparatus according to the first embodiment. The printer 1 is an electrophotographic full-color laser beam printer that forms toner images of four colors. As illustrated in FIG. 1, the printer 1 includes a feeding unit 20 that feeds stacked sheets S, a manual feeding unit 30, a sheet conveying device 100, and an image forming unit 50 that is an example of an image forming unit. And a control unit 60. The sheet conveying apparatus 100 includes a fixing unit 17 serving as a fixing unit that is an example of a conveying unit and disposed above the image forming unit 50, and a switching mechanism 70 disposed above the fixing unit 17. Further, the sheet conveying apparatus 100 includes a switchback roller pair 18 and a discharge roller pair 19 disposed in the vicinity of the switching mechanism 70. As an option, a document reading device that reads an image of a document may be provided.

  The image forming unit 50 forms a toner image as an image on the sheet S while conveying the sheet S under the control of the control unit 60. The control unit 60 receives an image formation command or image information input from an external computer or an original reading device connected to the printer 1, and starts an image forming process by the image forming unit 50 according to the image information in accordance with the command. .

  The image forming unit 50 includes the scanner unit 2, four process cartridges 3Y, 3M, 3C, and 3Bk that form images of four colors of yellow (Y), magenta (M), cyan (C), and black (Bk). It is equipped with. The four process cartridges 3Y, 3M, 3C, and 3Bk have the same configuration except that the colors of images to be formed are different. Only the image forming process of the process cartridge 3Y will be described, and the process cartridges 3M, 3C, and 3Bk will be described. Description is omitted.

  The scanner unit 2 irradiates laser light toward the photosensitive drum 4Y of the process cartridge 3Y based on the input image information. At this time, the photosensitive drum 4Y is charged in advance by the charging roller 5Y, and an electrostatic latent image is formed on the photosensitive drum 4Y by irradiation with laser light. Thereafter, the electrostatic latent image is developed by the developing roller 6Y, and a yellow (Y) toner image is formed on the photosensitive drum 4Y. Similarly, magenta (M), cyan (C), and black (Bk) toner images are formed on the photosensitive drums 4M, 4C, and 4Bk of the process cartridges 3M, 3C, and 3Bk.

  Each color toner image formed on each photosensitive drum is transferred to the intermediate transfer belt 8 by the primary transfer rollers 7Y, 7M, 7C, and 7Bk. The intermediate transfer belt 8 is wound around a driving roller 9 and a tension roller 10. The drive roller 9 is driven to rotate by a drive source (not shown), so that the intermediate transfer belt 8 rotates at a predetermined speed in the direction of arrow A in FIG.

  The image forming unit 50 includes a secondary transfer roller 11 and a secondary transfer counter roller 12 as secondary transfer units. The secondary transfer counter roller 12 is disposed to face the secondary transfer roller 11 with the intermediate transfer belt 8 interposed therebetween. The toner image primarily transferred onto the intermediate transfer belt 8 is conveyed to the secondary transfer roller 11 and the secondary transfer counter roller 12 as the intermediate transfer belt 8 rotates in the direction of arrow A. The image forming process for each color is performed at the timing of superimposing on the upstream toner image primarily transferred onto the intermediate transfer belt 8.

  In parallel with the above-described image forming process, the sheets S stacked on the cassette 24 of the feeding unit 20 are fed by the pickup roller 21. The sheets fed by the pickup roller 21 are separated one by one by a feed roller 22 and a separation roller 23, and conveyed toward the registration roller pair 13. When the sheet is fed from the manual feeding unit 30, the sheet is conveyed to the registration roller pair 13 by the pickup roller 14 and the conveying roller pair 15.

  The leading edge of the sheet S conveyed to the registration roller pair 13 is abutted against the rotation of the registration roller pair 13 that has stopped rotating, and skew feeding is corrected. Then, the sheet S is conveyed at a timing aligned with the toner image on the intermediate transfer belt 8.

  A full color toner image on the intermediate transfer belt 8 is transferred to the sheet S by the secondary transfer roller 11 and the secondary transfer counter roller 12. The toner remaining on the intermediate transfer belt 8 after the transfer is collected by the cleaning device 16. The sheet S on which the toner image is transferred is conveyed to the fixing unit 17. The fixing unit 17 includes a heating roller 17A and a pressure roller 17B. The sheet S to which the toner image has been transferred is given predetermined heat and pressure while being conveyed to the nip portion of the rotating heating roller 17A and pressure roller 17B, and the toner is melted and fixed. Then, the fixing unit 17 conveys the toner image to the switching mechanism 70 while fixing the toner image on the sheet S.

  The switching mechanism 70 has a switching member 71. Downstream of the switching member 71 in the sheet conveyance direction, the reverse conveyance path PT1 that is an example of the first conveyance path, which switches back the sheet S, and the sheet S that is an example of the second conveyance path are out of the machine ( A discharge conveyance path PT2 for discharge to the outside of the apparatus main body 1A is disposed. That is, the switching member 71 is disposed at a branch portion between the reverse conveyance path PT1 and the discharge conveyance path PT2. A switchback roller pair 18 is arranged in the reverse conveyance path PT1, and a discharge roller pair 19 is arranged in the discharge conveyance path PT2. The sheet S is conveyed to the switching member 71 by the fixing unit 17.

  The switching member 71 moves between a reverse position P1 that is a first position guided to the reverse conveyance path PT1 and a discharge position P2 that is a second position guided to the discharge conveyance path PT2. That is, by switching the position of the switching member 71, the conveyance path for conveying the sheet S is switched, and the sheet S is conveyed to one of the switchback roller pair 18 and the discharge roller pair 19. The sheet S conveyed to the discharge roller pair 19 is discharged by a discharge roller pair 19 to a discharge tray 25 provided on the upper surface of the apparatus main body 1A.

  When images are formed on both sides of the sheet S, the sheet S is conveyed to the switchback roller pair 18. The sheet S conveyed to the switchback roller pair 18 is switched back by the switchback roller pair 18 and conveyed to the double-sided conveyance path PT3. The sheet S conveyed to the double-sided conveyance path PT3 is conveyed again to the registration roller pair 13 in a state where the front and back and the front and back of the sheet S are reversed by the conveyance roller pairs 32 and 15. The toner image is transferred onto the sheet S by the secondary transfer roller 11 and the secondary transfer counter roller 12, and the toner image is fixed on the sheet S by the fixing unit 17. The sheet S on which the toner image is fixed is guided to the discharge roller pair 19 by the switching member 71 and is discharged to the discharge tray 25 by the discharge roller pair 19.

Hereinafter, the configuration of the switching mechanism 70 will be described in detail. FIG. 2 is a perspective view of the switching mechanism 70 in the first embodiment. The switching mechanism 70 includes the switching member 71 described above, a pair of frames 72 ₁ and 72 ₂ , a link arm 73 that is an example of a link member, a solenoid 74 that is an example of a drive unit, and an example of a second urging unit. And a coil spring 75.

A pair of frames 72 _1, 72 ₂ is supported on the apparatus body 1A shown in FIG. 1 in a state spaced from each other. Switching member 71 is movably supported by the pair of frames ₇₂ 1, 72 ₂ between the reversal position P1 and the discharge position P2. More specifically, the switching member 71 is supported by the arrow L1 direction and swingable pair of frames in the direction of the arrow L2 72 _1, 72 ₂ between the reversal position P1 and the discharge position P2. FIG. 2 shows a state where the switching member 71 has moved to the discharge position P2.

The switching member 71 is formed of a resin material having excellent slidability, and can perform a smooth switching operation. The switching member 71 includes a main body 71A, a shaft 71B that is integrally attached to the main body 71A, and an action portion 71C that is attached to an end of the shaft 71B. The body 71A has a pair of frames ₇₂ 1, 72 ₂ between, i.e. is arranged inside the pair of frames ₇₂ 1, 72 _2, the shaft 71B is supported by the pair of frames ₇₂ 1, 72 _2. Working portion attached to the shaft 71B 71C is located outside the pair of frames ₇₂ 1, 72 _2, are arranged on the side of one frame 72 _1.

Link arm 73, the solenoid 74 and the coil spring 75 is located outside the pair of frames ₇₂ 1, 72 _2, it is arranged on the side of one frame 72 _1.

The link arm 73 is formed of a resin material having excellent slidability. Link arm 73 swingably are supported by the frame 72 ₁ about the pivot shaft 73C. Hereinafter, pivot shaft 73C is described as a shaft which is fixed to the frame 72 _1, may be a shaft which is fixed to the link arm 73. One end (base end) 73A of the link arm 73 in the extending direction of the link arm is supported by the plunger 74A of the solenoid 74, and the other end (leading end) 73B of the link arm 73 in the extending direction of the link arm is the action of the switching member 71. It faces a part of the part 71C.

  The solenoid 74 drives the link arm 73 under the control of the control unit 60 shown in FIG. When the plunger 74A of the solenoid 74 moves in the direction of arrow N1 that is the suction direction, the other end 73B of the link arm 73 moves in the direction of arrow M1 that is the direction close to the action portion 71C. Further, when the plunger 74A moves in the direction of the arrow N2 that is the pushing direction, the other end 73B of the link arm 73 moves in the direction of the arrow M2 that is a direction away from the action portion 71C.

The solenoid 74 may be any of a push type, a pull type, and a push pull type, but is a pull type in the first embodiment. Coil spring 75 is a tension spring disposed between the working portion 71C of the frame 72 ₁ and the switching member 71. Therefore, when the acting portion 71C is urged in the direction of the arrow L2 by the urging force of the coil spring 75 and the energization of the solenoid 74 is in an off state, the switching member 71 is in the discharge position P2 (the position indicated by the solid line in FIG. 1). To position.

  When the control unit 60 controls the energization of the solenoid 74, a driving force is generated in the solenoid 74. The plunger 74A moves in the arrow N1 direction by the driving force of the solenoid 74. Then, the other end 73B of the link arm 73 moves in the arrow M1 direction and acts on the acting portion 71C, so that the acting portion 71C moves in the arrow L1 direction against the urging force of the coil spring 75. Thereby, the switching member 71 moves to the inversion position P1 (the position of the broken line in FIG. 1). When the solenoid 74 is a push-pull type, the coil spring 75 can be omitted.

Frame 72 _1, the abutting portion 72A is integrally provided. In the abutting portion 72A, an elastic member 81 which is an example of a first positioning unit and an elastic member 82 which is an example of a second positioning unit are arranged. A part of the action part 71 </ b> C of the switching member 71 comes into contact with the elastic member 82, so that the switching member 71 is positioned at the discharge position P <b> 2 (solid line position in FIG. 1). Further, when a part of the action portion 71C of the switching member 71 comes into contact with the elastic member 81, the switching member 71 is positioned at the reverse position P1 (the position indicated by the broken line in FIG. 1). The elastic members 81 and 82 are elastically deformable members, for example, rubber made of urethane foam. Note that the elastic members 81 and 82 may be disposed in the action portion 71C. In this case, the elastic members 81 and 82 come into contact with the abutting portion 72A.

  Between the switching member 71 and the link arm 73, more specifically, between the part of the action part 71 </ b> C of the switching member 71 and the other end 73 </ b> B of the link arm 73, an elastic member 80, which is an example of a deformation unit, is provided. Has been placed. The elastic member 80 may be fixed to either the action part 71C of the switching member 71 or the other end 73B of the link arm 73, but is fixed to the action part 71C of the switching member 71 in the first embodiment. . The elastic member 80 is a member that is elastically deformed, for example, rubber made of urethane foam. The elastic member 80 is formed of a member having a smaller elastic modulus than the elastic member 81 so that the elastic member 80 is pressed and deformed by the other end 73B of the link arm 73 when the switching member 71 is moved from the discharge position P2 to the reverse position P1. Yes. For example, the elastic member 80 is formed of urethane foam rubber made of a material different from that of the elastic member 81. The elastic members 80 and 81 may be made of urethane foam made of the same material, and the elastic modulus may be varied by changing the foaming rate and the compression rate. Further, one or both of the elastic members 80 and 81 may be springs instead of urethane foam. Similarly, the elastic member 82 may be a spring instead of urethane foam.

  Hereinafter, the operation of the switching mechanism 70 will be described in detail. FIG. 3A, FIG. 3B, and FIG. 3C are explanatory views showing the operation of the switching member 71 of the switching mechanism 70 in the first embodiment. 3A is an explanatory diagram showing a state in which the energization to the solenoid 74 is turned off, FIG. 3B is an explanatory diagram showing a state in which the energization to the solenoid 74 is switched from OFF to ON, and FIG. (c) is an explanatory view showing a state in which energization to the solenoid 74 is turned on. FIG. 3B illustrates a state in which the plunger 74A of the solenoid 74 is moving. 3A, 3B, and 3C, the coil spring 75 is not shown.

  When the energization to the solenoid 74 is in an off state, the driving force of the solenoid 74 is not generated, and the switching member 71 is caused by the biasing force by the coil spring 75 as shown in FIGS. 2 and 3A. It contacts the elastic member 82 and is positioned at the discharge position P2.

  The discharge position P2 is a position for guiding the sheet S conveyed to the fixing unit 17 to the discharge conveyance path PT2, that is, the discharge roller pair 19. In the first embodiment, the discharge position P <b> 2 is based on the position when the action portion 71 </ b> C of the switching member 71 contacts the non-compressed elastic member 82. The biasing force with which the coil spring 75 biases the switching member 71 is set to be smaller than the force required to deform the elastic member 82. Therefore, when the energization to the solenoid 74 is in an off state, the switching member 71 does not excessively enter from the place where the switching member 71 contacts the elastic member 82. That is, the amount of compressive deformation of the elastic member 82 is a minute predetermined amount. Therefore, the switching member 71 can be positioned with high accuracy at the discharge position P2.

When switching the transport path, the control unit 60 shown in FIG. 1 controls the energization of the solenoid 74 to be in an ON state. When energization of the solenoid 74 is turned on, the plunger 74A of the solenoid 74 moves in the direction of the arrow N1 as shown in FIG. 3B, and pulls one end 73A of the link arm 73 downward. Thus the link arm 73 about the pivot shaft 73C which is fixed to the frame 72 ₁ swings (rotates), the action portion of the switching member 71 and the other end 73B of the link arm 73 via the elastic member 80 71C Is pushed up in the direction of the arrow M1. As a result, the switching member 71 swings (rotates) in the direction of the arrow L1 about the shaft 71B. Then, the action portion 71C of the switching member 71 comes into contact with the elastic member 81 and moves to the reverse conveyance path PT1, that is, the reverse position P1 for guiding the sheet S to the switchback roller pair 18. In the first embodiment, the reversal position P1 is based on the position when the action portion 71C of the switching member 71 is in contact with the elastic member 81 in an uncompressed state.

  For each component constituting the switching mechanism 70, the link arm 73 swings in the direction of the arrow M1 that further pushes up the switching member 71 due to variation factors such as component tolerance, a minute gap in the fitting portion, and an assembly error. In the first embodiment, the elastic member 80 has a smaller elastic modulus than the elastic member 81. That is, when the same force is applied to the elastic member 80 and the elastic member 81, the amount of compressive deformation of the elastic member 80 is larger than the amount of compressive deformation of the elastic member 81. For this reason, the elastic member 80 is deformed as shown in FIG. 3 (c), and absorbs the amount excessively pressed by the link arm 73. Therefore, the amount of compressive deformation of the elastic member 81 can be suppressed to a minute predetermined amount. Therefore, the change in the position of the switching member 71 with respect to the reference position when the switching member 71 abuts against the elastic member 81 can be suppressed to a minute, and the switching member 71 can be positioned with high accuracy at the reverse position P1. That is, it is possible to suppress variations in the inversion position P1 due to variations in component tolerances and the like.

  When the switching member 71 is moved from the reverse position P1 to the discharge position P2, the energization to the solenoid 74 may be turned off. Thereby, there is no driving force in the solenoid 74, and the switching member 71 returns from the reverse position P1 to the discharge position P2 by the biasing force of the coil spring 75 (FIG. 2). Also in this case, since the amount of compressive deformation of the elastic member 82 can be suppressed to a minute, the change in position of the switching member 71 can be suppressed to a minute from the position in contact with the elastic member 82, and the switching member 71 is moved to the discharge position P2. Can be positioned with high accuracy.

  In addition, since the elastic members 81 and 82 are disposed in the abutting portion 72A, it is possible to suppress the generation of contact noise in the switching member 71.

  In the first embodiment, the other end 73 </ b> B of the link arm 73 is always in contact with the elastic member 80. Therefore, even if there is a variation such as part tolerance, when the switching member 71 is operated by the link arm 73, there is no shortage of movement in the switching member 71, and the switching member 71 is reliably moved to the reverse position P1. Can do. Further, the vibration of the link arm 73 can be absorbed by the elastic member 80, and the operation of the link arm 73 is stabilized. That is, since the switching operation of the switching member 71 is stabilized, the sheet S can be stably guided to the reverse conveyance path PT1 or the discharge conveyance path PT2.

[Second Embodiment]
Next, a printer that is an example of an image forming apparatus according to the second embodiment will be described. 4 is a perspective view of a printer switching mechanism 70A as an example of an image forming apparatus according to the second embodiment, and FIG. 5 is an enlarged view of a region V shown in FIG. Note that the configuration of the switching mechanism 70A in the printer of the second embodiment is different from the configuration of the switching mechanism 70 of the first embodiment. Other configurations of the printer of the second embodiment are the same as those of the first embodiment, and thus the description thereof is omitted. In addition, in the switching mechanism 70A in FIGS. 4 and 5, the same components as those of the switching mechanism 70 of the first embodiment are denoted by the same reference numerals and description thereof is omitted.

Similarly to the first embodiment, the switching mechanism 70A includes a switching member 71, a pair of frames 72 ₁ and 72 ₂ , and a link arm 73 that is an example of a link member. The switching mechanism 70A includes a solenoid 74 that is an example of a drive unit, a coil spring 75 that is an example of a second urging unit, and elastic members 81 and 82 that are examples of first and second positioning units. Yes.

  The switching mechanism 70A includes a deformation mechanism 40 that is an example of a deformation unit. The deformation mechanism 40 is disposed between the switching member 71 and the link arm 73, specifically, between the action portion 71 </ b> C of the switching member 71 and the other end 73 </ b> B of the link arm 73. The deformation mechanism 40 is pressed and deformed by the other end 73B of the link arm 73 when the switching member 71 is moved from the discharge position P2 to the reverse position P1.

  Hereinafter, the deformation mechanism 40 will be described in detail. Hereinafter, although the case where the deformation | transformation mechanism 40 is attached to the action part 71C of the switching member 71 is demonstrated, you may attach to the other end 73B of the link arm 73. FIG.

  The deformation mechanism 40 is disposed at a position in contact with the other end 73B of the link arm 73, and has a swinging member 41 supported by a working portion 71C of the switching member 71 so as to be swingable about a swinging shaft 41C. The deformation mechanism 40 includes a torsion coil spring 43 that is an example of a first urging unit that urges the swing member 41 toward the other end 73 </ b> B of the link arm 73. By this torsion coil spring 43, the swing member 41 is urged in a direction to contact the link arm 73. The first urging means is not limited to the torsion coil spring 43, and may be another spring such as a leaf spring or may be constituted by an elastic member other than the spring.

  When the swing member 41 receives a force less than a predetermined force in the direction of the arrow O1 opposite to the other end 73B side of the link arm 73, the swing member 41 has a predetermined posture with respect to the action portion 71C of the switching member 71. Keep. When the swing member 41 receives a force greater than or equal to a predetermined force in the arrow O1 direction, the swing member 41 swings in the arrow O1 direction about the swing shaft 41C on the switching member 71. Conversely, when the force received by the swing member 41 changes to less than a predetermined force, the swing member 41 swings (returns) to a predetermined posture in the direction of the arrow O2 opposite to the direction of the arrow O1. The force required for the swing member 41 of the deformation mechanism 40 to swing in the direction of the arrow O1 is smaller than the force required for the elastic member 81 to deform. That is, when the swinging member 41 is pressed in the direction of the arrow M1 by the other end 73B of the link arm 73 in a state where the action portion 71C of the switching member 71 is not in contact with the elastic member 81, the action portion 71C is moved in the direction of the arrow L1. It swings and the swing member 41 hardly swings with respect to the action part 71C. Further, when the swing member 41 is pressed against the other end 73B of the link arm 73 in the direction of the arrow M1 in a state where the action portion 71C of the switching member 71 is in contact with the elastic member 81, the action portion 71C hardly swings. The swing member 41 swings in the arrow O1 direction with respect to the action portion 71C.

  Hereinafter, the operation of the switching mechanism 70A will be described in detail. FIG. 6A, FIG. 6B, and FIG. 6C are explanatory views showing the operation of the switching member 71 of the switching mechanism 70A in the second embodiment. 6A is an explanatory view showing a state where the energization to the solenoid 74 is turned off, FIG. 6B is an explanatory view showing a state where the energization to the solenoid 74 is switched from OFF to ON, and FIG. (c) is an explanatory view showing a state in which energization to the solenoid 74 is turned on. FIG. 6B illustrates a state in which the plunger 74A of the solenoid 74 is moving. In FIG. 6A, FIG. 6B, and FIG. 6C, the coil spring 75 is not shown.

  When the energization of the solenoid 74 is in an off state, the driving force of the solenoid 74 is not generated, and the switching member 71 is driven by the biasing force of the coil spring 75 as shown in FIGS. 4 and 6A. It contacts the elastic member 82 and is positioned at the discharge position P2.

  The discharge position P2 is a position for guiding the sheet S conveyed to the fixing unit 17 to the discharge conveyance path PT2, that is, the discharge roller pair 19. In the second embodiment, the discharge position P <b> 2 is based on the position when the action portion 71 </ b> C of the switching member 71 contacts the non-compressed elastic member 82. The biasing force with which the coil spring 75 biases the switching member 71 is set to be smaller than the force required to deform the elastic member 82. Therefore, when the energization to the solenoid 74 is in an off state, the switching member 71 does not excessively enter from the place where the switching member 71 contacts the elastic member 82. That is, the amount of compressive deformation of the elastic member 82 is a minute predetermined amount. Therefore, the switching member 71 can be positioned with high accuracy at the discharge position P2.

When switching the transport path, the control unit 60 shown in FIG. 1 controls the energization of the solenoid 74 to be in an ON state. When energization to the solenoid 74 is turned on, the plunger 74A of the solenoid 74 moves in the direction of the arrow N1 as shown in FIG. 6B, and pulls one end 73A of the link arm 73 downward. Thus the link arm 73 swings (rotates) about the pivot shaft 73C which is fixed to the frame 72 _1, the action of the switching member 71 and the other end 73B of the link arm 73 via the swinging member 41 71C is pushed up in the direction of arrow M1. As a result, the switching member 71 swings (rotates) in the direction of the arrow L1 about the shaft 71B. Then, the action portion 71C of the switching member 71 comes into contact with the elastic member 81 and moves to the reverse conveyance path PT1, that is, the reverse position P1 for guiding the sheet S to the switchback roller pair 18. In the second embodiment, the reversal position P1 is based on the position when the action portion 71C of the switching member 71 contacts the elastic member 81 in an uncompressed state.

  In each component constituting the switching mechanism 70, the link arm 73 swings in the direction of the arrow M1 that further pushes up the switching member 71 due to variation factors such as component tolerance, a minute gap in the fitting portion, and an assembly error. In the second embodiment, when the same force is applied to the swing member 41 and the elastic member 81, the amount of displacement at the location where the other end 73 </ b> B of the link arm 73 contacts on the swing member 41 is the compressive deformation of the elastic member 81. It is set to be smaller than the amount (displacement amount). The swing member 41 swings in the direction of the arrow O1 as shown in FIG. 6C against the urging force of the torsion coil spring 43, and absorbs the amount excessively pressed by the link arm 73. Therefore, the amount of compressive deformation of the elastic member 81 can be suppressed to a minute predetermined amount. For this reason, a change in the position of the switching member 71 with respect to the reference position when the switching member 71 contacts the elastic member 81 can be suppressed to a small extent, and the switching member 71 can be positioned at the reverse position P1 with high accuracy. That is, it is possible to suppress variations in the inversion position P1 due to variations in component tolerances and the like.

  When the switching member 71 is moved from the reverse position P1 to the discharge position P2, the energization to the solenoid 74 may be turned off. Thereby, there is no driving force in the solenoid 74, and the switching member 71 returns from the reverse position P1 to the discharge position P2 by the biasing force of the coil spring 75 (FIG. 4). Also in this case, since the amount of compressive deformation of the elastic member 82 can be suppressed to a minute, the change in position of the switching member 71 can be suppressed to a minute from the position in contact with the elastic member 82, and the switching member 71 is moved to the discharge position P2. Can be positioned with high accuracy.

  In addition, since the elastic members 81 and 82 are disposed in the abutting portion 72A, it is possible to suppress the generation of contact noise in the switching member 71.

  In the second embodiment, the other end 73 </ b> B of the link arm 73 is always in contact with the swing member 41 urged by the torsion coil spring 43. Therefore, even if there is a variation such as part tolerance, when the switching member 71 is operated by the link arm 73, there is no shortage of movement in the switching member 71, and the switching member 71 is reliably moved to the reverse position P1. Can do. Further, the vibration of the link arm 73 can be absorbed by the swing member 41, and the operation of the link arm 73 is stabilized. That is, since the switching operation of the switching member 71 is stabilized, the sheet S can be stably guided to the reverse conveyance path PT1 or the discharge conveyance path PT2.

  The present invention is not limited to the embodiment described above, and many modifications are possible within the technical idea of the present invention. In addition, the effects described in the embodiments are merely a list of the most preferable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the embodiments.

  In 1st and 2nd embodiment, although the reference | standard of the inversion position P1 demonstrated the case where it was set as the position when the action part 71C of the switching member 71 contact | abutted to the elastic member 81 of a non-compression state, it limits to this. It is not a thing. A state in which the elastic member 81 is compressed by a predetermined amount may be used as a reference for the inversion position P1. Similarly, in the first and second embodiments, the case where the reference of the discharge position P2 is the position when the action portion 71C of the switching member 71 contacts the elastic member 82 in the non-compressed state has been described. It is not limited to. A state where the elastic member 82 is compressed by a predetermined amount may be used as the reference of the discharge position P2.

  In the first and second embodiments, the case has been described in which the first transport path switched by the switching member is the reverse transport path PT1, and the second transport path is the discharge transport path PT2, but the present invention is not limited thereto. is not. The first transport path may be the discharge transport path PT2, and the second transport path may be the reverse transport path PT1. Further, the first or second transport path may be a transport path other than the reverse transport path PT1 and the discharge transport path PT2.

  In the first and second embodiments, the printer is described as an example of the image forming apparatus. However, the present invention is not limited to this. The present invention can also be applied to an image forming apparatus such as a copying machine, a facsimile machine, or a multifunction machine, and a sheet conveying apparatus attached to the image forming apparatus. The present invention can also be applied to sheet conveying apparatuses other than the sheet conveying apparatus applied to the image forming apparatus.

DESCRIPTION OF SYMBOLS 1 ... Printer (image forming apparatus), 17 ... Fixing unit (conveying means), 50 ... Image forming part (image forming means), 71 ... Switching member, 73 ... Link arm (link member), 74 ... Solenoid (driving means) , 80 ... elastic member (deformation means), 81 ... elastic member (first positioning means), 82 ... elastic member (second positioning means), 100 ... sheet conveying device, P1 ... reverse position (first position), P2 ... Discharge position (second position), PT1... Reverse conveyance path (first conveyance path), PT2 ... discharge conveyance path (second conveyance path)

Claims (10)

Conveying means for conveying the sheet;
A switching member movable between a first position for guiding the sheet conveyed to the conveying means to the first conveying path and a second position for guiding the sheet conveyed to the conveying means to the second conveying path; ,
A link member that acts on the switching member to move the switching member between the first position and the second position;
Driving means for driving the link member so that the switching member moves to the first position;
First positioning means for positioning the switching member at the first position;
A deformation means disposed between the switching member and the link member and deformed by being pressed by the link member when the switching member is moved to the first position;
A sheet conveying apparatus. The first positioning means is a member that is elastically deformed.
The sheet conveying apparatus according to claim 1. The deformation means is an elastically deformable member having an elastic modulus smaller than that of the first positioning means.
The sheet conveying apparatus according to claim 2, The deformation means includes
A swing member disposed at a position in contact with the link member and supported swingably by the switching member;
First urging means for urging the rocking member toward the link member;
The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is a sheet conveying apparatus. A displacement amount of the rocking member at a location where the link member contacts is smaller than a displacement amount of the first positioning means;
The sheet conveying apparatus according to claim 4. A second positioning means for positioning the switching member at the second position;
The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is a sheet conveying apparatus. The second positioning means is a member that is elastically deformed.
The sheet conveying apparatus according to claim 6. A second urging means for urging the switching member to the second position;
The driving means generates a driving force for moving the switching member to the first position against an urging force of the second urging means;
The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is a sheet conveying apparatus. A pair of frames that support the switching member in a swingable manner between the first position and the second position;
The link member, the first positioning means, and the deformation means are arranged outside the pair of frames.
The sheet conveying apparatus according to claim 1, wherein the sheet conveying apparatus is a sheet conveying apparatus. A sheet conveying device according to any one of claims 1 to 9,
Image forming means for forming an image on a sheet,
An image forming apparatus.

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