Drive device

Abstract

To provide a drive device which can smoothly move a lever even when a solenoid is down-sized.SOLUTION: A drive device 7 includes: a paper discharge roller 64a; a solenoid 94; a lever 73 movable between a first position of being pulled by the solenoid 94 and a second position where the pulling by the solenoid 94 is cancelled and having a boss 931; a first intermediate input gear 73 for transmitting a drive force to the paper discharge roller 64a; a pendulum gear 72 movable between a third position of being engaged with the intermediate input gear 73 and a fourth position where the engagement with the intermediate input gear 73 is cancelled in cooperation with the movement of the lever 73; and a gear frame 91 having a support shaft 912 inserted into the boss 931. The support shaft 912 includes: a first contact part 912A brought into contact with the boss 931; a second contact part 912B separated from the first contact part 912A in a right-left direction and brought into contact with the boss 931; and a separation part 912C positioned between the first contact part 912A and the second contact part 912B with a gap from an inner peripheral face of the boss 931.SELECTED DRAWING: Figure 9

Description

Technical Field

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

Background Art

[0002] Conventionally, as disclosed in Patent Document 1, in an image forming apparatus capable of double-sided printing for forming images on both sides of a sheet, a driving device using a solenoid for switching between forward rotation and reverse rotation of a paper discharge roller for conveying the sheet is provided.

[0003] The driving device includes a lever that can move between a first position pulled by the solenoid and a second position where the pulling by the solenoid is released. For example, when the lever moves to the second position, the paper discharge roller rotates forward, and when the lever moves to the first position, the paper discharge roller is reversed.

[0004] The forward-rotating paper discharge roller conveys a sheet with an image formed on one side toward the paper discharge tray, and the reverse-rotating paper discharge roller conveys a sheet with an image formed on one side toward the image forming unit. The lever is movably supported by other members such as a frame.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In recent years, with the miniaturization of driving devices, it has been required to miniaturize solenoids. When the solenoid is miniaturized, the suction force of the solenoid for moving the lever becomes smaller. Therefore, if a force that inhibits the movement of the lever, such as the frictional force between the lever and the member supporting the lever, becomes large, there is a possibility that the lever cannot be smoothly moved by the solenoid.

[0007] Therefore, the present invention provides a driving device capable of smoothly moving a lever even when a solenoid is miniaturized.

Means for Solving the Problems

[0008] The driving device for solving the above problems has the following characteristics.

[0009] That is, the driving device includes a conveying roller extending in the axial direction, a solenoid, and a lever engaged with the solenoid. The lever is movable between a first position pulled by the solenoid and a second position where the pulling by the solenoid is released, and includes a boss protruding in the axial direction. The driving device further includes a first gear that transmits a driving force to the conveying roller, and a pendulum gear that is movable between a third position meshing with the first gear and a fourth position where the meshing with the first gear is released in conjunction with the movement of the lever. The driving device also includes a frame extending along the axial direction and having a support shaft inserted into the boss of the lever. The support shaft includes a first contact portion that contacts the boss of the lever, a second contact portion that is spaced apart from the first contact portion in the axial direction and contacts the boss of the lever, and a separation portion that is positioned with a gap from the inner peripheral surface of the boss between the first contact portion and the second contact portion.

[0010] In this way, since the lever is supported at two locations, i.e., the first contact portion and the second contact portion, sandwiching the separation portion of the support shaft of the frame, the frictional force generated between the lever and the support shaft can be reduced as compared with the case where the lever is entirely supported by the outer periphery of the support shaft. Therefore, even when the lever is moved using a miniaturized solenoid with a small attractive force, the lever can be smoothly moved. Furthermore, by supporting the lever with the support shaft of the frame which is a single component, it is possible to improve the positional accuracy of the portion supporting the lever with respect to the lever as compared with the case where the lever is supported across two components. Thereby, it is possible to suppress the displacement of the position between the lever and the portion supporting the lever, reduce the kinking during the operation of the lever, and smoothly move the lever.

[0011] Also, the lever includes a solenoid contact portion with which the solenoid comes into contact, and the solenoid contact portion is located between the first contact portion and the second contact portion in the axial direction.

[0012] Thereby, when the force acting on the lever pulled by the solenoid is applied to the support shaft, it is possible to suppress the force applied to the support shaft from being biased to one of the first contact portion and the second contact portion. Therefore, even when moving the lever using a solenoid with a reduced size and a small attracting force, the lever can be smoothly moved.

[0013] The apparatus also includes a second gear to which a driving force is input, a sector gear including a tooth portion that can mesh with the second gear, and an engaging portion that can engage with the lever. The lever includes a solenoid contact portion with which the solenoid comes into contact, and an engaging claw that can engage with the engaging portion of the sector gear. The engaging claw of the lever is located between the first contact portion and the second contact portion in the axial direction.

[0014] Thereby, when the force acting on the lever that engages with the sector gear is applied to the support shaft, it is possible to suppress the force applied to the support shaft from being biased to one of the first contact portion and the second contact portion. Therefore, even when moving the lever using a solenoid with a reduced size and a small attracting force, the lever can be smoothly moved.

[0015] Further, the solenoid contact portion of the lever protrudes from the boss in a direction orthogonal to the axial direction, the engaging claw of the lever protrudes from the boss in a direction orthogonal to the axial direction at a phase different from that of the solenoid contact portion, and the lever includes a connecting wall that connects the solenoid contact portion and the engaging claw.

[0016] When a force from the solenoid is applied to the solenoid contact portion and a force from the sector gear is applied to the engaging claw, a force acting in a direction in which the solenoid contact portion and the engaging claw separate acts on the solenoid contact portion and the engaging claw. However, since the solenoid contact portion and the engaging claw are connected by the connecting wall, it is possible to suppress the separation of the solenoid contact portion and the engaging claw. Thereby, when the solenoid contact portion is pulled by the solenoid and moves to the first position, the engagement state between the engaging claw and the engagement portion of the sector gear can be appropriately released.

[0017] The solenoid includes a plunger movable in the pulling direction of the lever, a coil into which the plunger is movably inserted, and a case covering the coil. The case includes a case side surface located on the opposite side of the frame sandwiching the coil in the axial direction, and a fastening hole into which a fastening member for fixing the case to the frame is inserted is formed in the case side surface.

[0018] If the fastening hole is formed in the case side surface on the side adjacent to the frame, the fastening member protrudes toward the frame side more than the solenoid. However, if the fastening hole is formed in the case side surface on the opposite side of the frame sandwiching the coil, the portion of the fastening member screwed to the frame can be accommodated within the thickness range of the solenoid in the axial direction. Thereby, it is possible to suppress the fastening member from protruding toward the frame side more than the solenoid and to reduce the size of the device in the axial direction.

[0019] It also includes an output gear to which the driving force from the first gear is transmitted and which is connected to the conveying roller, and the output gear is located at a position overlapping the solenoid in the vertical direction.

[0020] Accordingly, when the output gear is disposed above the solenoid, the size of the device in the vertical direction can be reduced as compared with the case where the output gear is disposed below the solenoid.

[0021] Further, a switch arm that supports the pendulum gear and moves the pendulum gear between the third position and the fourth position in conjunction with the movement of the lever, and a cover that covers the switch arm from the opposite side of the frame sandwiching the switch arm in the axial direction are provided, and the switch arm is provided with a notch that cuts out a part on the cover side in the axial direction.

[0022] Accordingly, interference between the switch arm and the cover can be suppressed, and the operation of the switch arm is not hindered by the cover.

[0023] Further, the frame is a gear cover that covers the first gear and the pendulum gear.

[0024] Accordingly, it is not necessary to provide a member forming the support shaft separately from the frame that is originally required to cover each gear, and the number of parts can be reduced.

[0025] Further, the first contact portion is disposed at a position closer to the tip of the support shaft than the second contact portion, and the diameter of the second contact portion is larger than the diameter of the first contact portion.

[0026] Accordingly, the assemblability of the lever with respect to the support shaft when assembling the lever and the support shaft can be improved.

Advantages of the Invention

[0027] According to the present invention, even when the lever is moved using a solenoid having a reduced size and a small attractive force, the lever can be moved smoothly.

Brief Description of the Drawings

[0028]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Embodiments for Carrying Out the Invention

[0029] Next, embodiments for carrying out the present invention will be described with reference to the accompanying drawings.

[0030] [Image Forming Apparatus] The image forming apparatus 1 shown in FIG. 1 is an embodiment of an image forming apparatus provided with the drive device according to the present invention, and is a color laser printer that forms a multi-color image on a sheet S by an electrophotographic method.

[0031] In the following description, the left side in FIG. 1 is defined as the front side of the image forming apparatus 1, the right side in FIG. 1 is defined as the rear side of the image forming apparatus 1, the front side of the paper surface in FIG. 1 is defined as the right side of the image forming apparatus 1, and the back side of the paper surface in FIG. 1 is defined as the left side of the image forming apparatus 1. Also, the upper side and the lower side in FIG. 1 are defined as the upper side and the lower side of the image forming apparatus 1, respectively.

[0032] The image forming apparatus 1 includes an apparatus main body 2, a paper feeding unit 3 having a paper feeding tray 10 that supports a sheet S and a sheet conveying unit 30 that conveys the sheet S, and an image forming unit 5 that forms an image on the sheet S conveyed by the paper feeding unit 3.

[0033] The apparatus main body 2 is formed in a substantially rectangular parallelepiped shape and houses the paper feeding unit 3 and the image forming unit 5. A front opening 2A is open on the front surface of the apparatus main body 2, and the apparatus main body 2 has a front cover 21 that can open and close the front opening 2A.

[0034] The front cover 21 is configured to be rotatable about a rotation axis 21a at the lower end, and by rotating about the rotation axis 21a, it can move between a closed position where the front opening 2A is closed and an open position where the front opening 2A is opened. A paper discharge tray 22 that slopes downward from the front side to the rear side is formed on the upper surface of the apparatus main body 2.

[0035] The paper feeding unit 3 is disposed at the lower part of the apparatus main body 2 and conveys the sheet S supported by the paper feeding tray 10 to the image forming unit 5 by the sheet conveying unit 30. The paper feeding tray 10 is configured to be slidable in the front-rear direction and is configured to be movable between a storage position where it is stored in the apparatus main body 2 and a separation position where it is pulled forward from the storage position.

[0036] The sheet conveying unit 30 includes a paper feeding roller 32, a separation roller 33, a separation pad 33a, a pair of conveying rollers 34, and a pair of registration rollers 35. Inside the apparatus main body 2, a conveyance path P1 for the sheet S from the paper feeding tray 10 via the image forming unit 5 to the paper discharge tray 22 is configured.

[0037] The sheet S supported by the paper feed tray 10 is separated one by one by the paper feed roller 32, the separation roller 33, and the separation pad 33a and sent out to the conveyance path P1. The paper feed roller 32 is a roller that conveys the sheet S from the paper feed tray 10 toward the image forming unit 5. The separation roller 33 and the separation pad 33a constitute separation means for separating the sheets S supported by the paper feed tray 10 one by one.

[0038] The sheet S sent out to the conveyance path P1 is conveyed toward the image forming unit 5 by the pair of conveyance rollers 34 and the pair of registration rollers 35. The pair of registration rollers 35 restricts the movement of the leading end of the conveyed sheet S and temporarily stops it, and then conveys the sheet S toward the image forming unit 5 at a predetermined timing.

[0039] The image forming unit 5 is disposed above the paper feed unit 3 and includes four toner cartridges 50 arranged side by side in the front-rear direction and a photosensitive drum 51 corresponding to each toner cartridge 50. Each toner cartridge 50 is provided corresponding to each color of black, yellow, magenta, and cyan. The toner cartridge 50 is detachably supported by the drawer 59. The drawer 59 is detachable from the apparatus main body 2 through the front opening 2A in the apparatus main body 2 by opening the front cover 21. The toner cartridge 50 includes a developing roller 52.

[0040] The photosensitive drum 51 is formed in a substantially cylindrical shape with the left-right direction as the axial direction and is rotatably supported by the drawer 59. The developing roller 52 extends in the left-right direction and is rotatably supported by the toner cartridge 50. Toner is an example of a developer. The developing roller 52 supplies toner to the photosensitive drum 51.

[0041] The apparatus main body 2 has an exposure device 56 that exposes the surface of the photosensitive drum 51. The exposure device 56 includes a laser diode, a polarizer, a lens, and a mirror (not shown). The exposure device 56 is configured to emit a light beam to each photosensitive drum 51 and expose the surface of each photosensitive drum 51.

[0042] Below the conveyance path P1 of the photosensitive drum 51, the transfer belt 41 is disposed opposite. The transfer belt 41 is in contact with the photosensitive drum 51. The transfer belt 41 is stretched between the drive roller 42 and the driven roller 43 disposed in front of the drive roller 42. Transfer rollers 44 are respectively disposed at positions facing the respective photosensitive drums 51 sandwiching the transfer belt 41. In the image forming unit 5, the belt device 40 is constituted by the transfer belt 41, the drive roller 42, the driven roller 43, the transfer roller 44, and the like.

[0043] The image forming unit 5 includes a charger 54 for charging each photosensitive drum 51. The charger 54 is supported by the drawer 59. The photosensitive drum 51 uniformly charged by the charger 54 is selectively exposed by the exposure device 56 respectively. By this exposure, charges are selectively removed from the surface of the photosensitive drum 51, and an electrostatic latent image is formed on the surface of the photosensitive drum 51.

[0044] The toner accommodated in the toner cartridge 50 is charged to a positive polarity and carried on the surface of the developing roller 52. A developing bias is applied to the developing roller 52. When the electrostatic latent image formed on the photosensitive drum 51 faces the developing roller 52, toner is supplied from the developing roller 52 to the electrostatic latent image due to the potential difference between the electrostatic latent image and the developing roller 52. Thereby, a toner image is formed on the surface of the photosensitive drum 51.

[0045] When the sheet S conveyed toward the image forming unit 5 reaches the transfer belt 41, it is conveyed by the transfer belt 41 and sequentially passes between the transfer belt 41 and each photosensitive drum 51. Then, the toner image carried on the surface of the photosensitive drum 51 is transferred to the sheet S by the transfer bias applied to the transfer roller 44 when facing the sheet S.

[0046] Note that the transfer belt 41 in this embodiment is configured as a conveyance belt that conveys the sheet S onto which the toner image is transferred. However, it is also possible to configure it as an intermediate transfer belt onto which the toner image is transferred to the belt itself and the toner image transferred to the belt is further transferred to the sheet S.

[0047] The sheet S onto which the toner image is transferred is conveyed to the fixing device 60. The fixing device 60 includes a heating roller 61 and a pressure roller 62 that is pressed against the heating roller 61. The toner image on the sheet S conveyed to the fixing device 60 is thermally fixed while passing between the heating roller 61 and the pressure roller 62. That is, the fixing device 60 fixes the toner image on the sheet S.

[0048] The sheet S on which the toner image is thermally fixed is conveyed downstream in the conveyance direction from the fixing device 60. Downstream in the conveyance direction of the fixing device 60, an intermediate paper discharge roller 63a and a driven roller 63b arranged to face the intermediate paper discharge roller 63a are arranged. Downstream in the conveyance direction of the intermediate paper discharge roller 63a and the driven roller 63b, a paper discharge roller 64a and a driven roller 64b arranged to face the paper discharge roller 64a are arranged.

[0049] The sheet conveyed downstream in the conveyance direction from the fixing device 60 is conveyed by the intermediate paper discharge roller 63a and the driven roller 63b, and further conveyed by the paper discharge roller 64a and the driven roller 64b, and discharged to the paper discharge tray 22.

[0050] In the image forming apparatus 1, a process unit PU that forms a toner image on the sheet S is configured by a drawer 59, a toner cartridge 50 supported by the drawer 59, a photosensitive drum 51, a charger 54, and the like. Note that the process unit PU only needs to include at least the photosensitive drum 51 and the charger 54, and may include the transfer belt 41 or the fixing device 60.

[0051] The image forming apparatus 1 includes a power supply board 11 on which a power supply circuit is formed, and a board cover 12 that covers the power supply board 11. The board cover 12 is disposed between a paper feed tray 10 and a belt device 40 at the rear part inside the apparatus main body 2. The apparatus main body 2 houses a process unit PU and the board cover 12.

[0052] The paper discharge roller 64a and the intermediate paper discharge roller 63a are rotatably supported by the apparatus main body 2 in a posture where the axial direction is along the left - right direction. The paper discharge roller 64a and the intermediate paper discharge roller 63a extend along the axial direction. The paper discharge roller 64a is an example of a conveyance roller.

[0053] The paper discharge roller 64a and the intermediate paper discharge roller 63a are configured to be rotatable in a normal rotation direction, which is the rotation direction when conveying the sheet S toward the paper discharge tray 22 side, and a reverse rotation direction, which is the rotation direction opposite to the normal rotation direction. The image forming apparatus 1 has a re - conveyance path P2 that guides the sheet S conveyed along the conveyance path P1 and passed through the fixing device 6 to the conveyance path P1 on the upstream side in the sheet conveyance direction from the registration roller pair 35.

[0054] The re - conveyance path P2 branches from the conveyance path P1 at a branch point Pb located between the fixing device 6 and the intermediate paper discharge roller 63a, then extends forward between the board cover 12 and the paper feed tray 10, and merges with the conveyance path P1 at a merging point Pa located between the conveyance roller pair 34 and the registration roller pair 35.

[0055] The sheet S conveyed from the fixing device 6 to the paper discharge roller 64a can be conveyed again to the image forming unit 5 through the re - conveyance path P2 by rotating the paper discharge roller 64a and the intermediate paper discharge roller 63a in the reverse rotation direction. The sheet S conveyed to the re - conveyance path P2 by the paper discharge roller 64a and the intermediate paper discharge roller 63a is conveyed toward the image forming unit 5 side by the first re - conveyance roller pair 36 and the second re - conveyance roller pair 37 provided on the re - conveyance path P2.

[0056] The image forming apparatus 1 can perform duplex printing in which a sheet S with an image formed on one surface is conveyed again to the image forming unit 5 through the re-conveying path P2 and an image is formed on the other surface of the sheet S.

[0057] [Drive device] As shown in FIG. 1, the image forming apparatus 1 includes a drive device 7 that switches the rotation directions of the paper discharge roller 64a and the intermediate paper discharge roller 63a between the normal rotation direction and the reverse rotation direction. The drive device 7 is located at the left end and the rear end of the apparatus main body 2.

[0058] As shown in FIGS. 2 to 4, the drive device 7 includes a gear frame 91, an input gear 70, a drive gear 71, a pendulum gear 72, a first intermediate input gear 73, a second intermediate input gear 74, a first idler gear 75, a second idler gear 76, a third idler gear 77, a paper discharge roller gear 78, and an intermediate paper discharge roller gear 79. The first intermediate input gear 73 is an example of a first gear that transmits a driving force to the conveyance roller. The drive gear 71 is an example of a second gear to which a driving force is input.

[0059] The gear frame 91 includes a support wall 911 that extends in the front-rear direction and the up-down direction. The support wall 911 faces in the left-right direction. The gear frame 91 is supported by the apparatus main body 2. The gear frame 91 is a gear cover that covers each of the gears 70 to 79.

[0060] Among the gears 70 to 79, the input gear 70, the drive gear 71, the first intermediate input gear 73, the second intermediate input gear 74, the first idler gear 75, the second idler gear 76, the third idler gear 77, the paper discharge roller gear 78, and the intermediate paper discharge roller gear 79 excluding the pendulum gear 72 are rotatably supported by the support wall 911 of the gear frame 91 in a posture where the rotation axis direction is the left-right direction. Each of the gears 70 to 79 is located to the left of the support wall 911.

[0061] The driving force from the drive source provided in the image forming apparatus 1 is transmitted to the input gear 70. The drive gear 71 meshes with the input gear 70, and the driving force is input to the drive gear 71 from the input gear 70.

[0062] The pendulum gear 72 meshes with the drive gear 71. The first intermediate input gear 73 and the second intermediate input gear 74 are each configured to be able to mesh with the pendulum gear 72.

[0063] The pendulum gear 72 is movable to a third position where it meshes with the first intermediate input gear 73 and a fourth position where it meshes with the second intermediate input gear 74. When the pendulum gear 72 is in the third position and meshing with the first intermediate input gear 73, the pendulum gear 72 is separated from the second intermediate input gear 74. When the pendulum gear 72 is in the fourth position and meshing with the second intermediate input gear 74, the pendulum gear 72 is separated from the first intermediate input gear 73.

[0064] The first idle gear 75 is a two-stage gear in which a large-diameter gear 751 formed relatively large in diameter and a small-diameter gear 752 formed relatively small in diameter are stacked in two stages. The large-diameter gear 751 meshes with the first intermediate input gear 73.

[0065] The second idle gear 76 is a two-stage gear in which a small-diameter gear 761 formed relatively small in diameter and a large-diameter gear 762 formed relatively large in diameter are stacked in two stages. The small-diameter gear 761 meshes with the small-diameter gear 752 of the first idle gear 75. The large-diameter gear 762 meshes with the second intermediate input gear 74.

[0066] The third idle gear 77 meshes with the small-diameter gear 761 of the second idle gear 76. The paper discharge roller gear 78 meshes with the third idle gear 77. The paper discharge roller gear 78 is connected to the paper discharge roller 64a, and the paper discharge roller gear 78 and the paper discharge roller 64a can rotate integrally. The paper discharge roller gear 78 is an example of an output gear to which the driving force from the first gear is transmitted and which is connected to the conveyance roller.

[0067] The intermediate paper discharge roller gear 79 meshes with the first intermediate input gear 73. The intermediate paper discharge roller gear 79 is connected to the intermediate paper discharge roller 63a, and the intermediate paper discharge roller gear 79 and the intermediate paper discharge roller 63a can rotate integrally.

[0068] When the pendulum gear 72 is in the third position and meshes with the first intermediate input gear 73, the driving force input from the input gear 70 to the driving gear 71 is transmitted to the paper discharge roller 64a via the pendulum gear 72, the first intermediate input gear 73, the first idle gear 75, the second idle gear 76, the third idle gear 77, and the paper discharge roller gear 78. The paper discharge roller 64a to which the driving force is transmitted rotates in the forward rotation direction.

[0069] Also, when the pendulum gear 72 is in the third position and meshes with the first intermediate input gear 73, the driving force input from the input gear 70 to the driving gear 71 is transmitted to the intermediate paper discharge roller 63a via the pendulum gear 72, the first intermediate input gear 73, and the intermediate paper discharge roller gear 79. The intermediate paper discharge roller 63a to which the driving force is transmitted rotates in the forward rotation direction.

[0070] When the pendulum gear 72 is in the fourth position and meshes with the second intermediate input gear 74, the driving force input from the input gear 70 to the driving gear 71 is transmitted to the paper discharge roller 64a via the pendulum gear 72, the second intermediate input gear 74, the second idle gear 76, the third idle gear 77, and the paper discharge roller gear 78. The paper discharge roller 64a to which the driving force is transmitted rotates in the reverse rotation direction.

[0071] Also, when the pendulum gear 72 is in the fourth position and meshes with the second intermediate input gear 74, the driving force input from the input gear 70 to the driving gear 71 is transmitted to the intermediate paper discharge roller 63a via the pendulum gear 72, the second intermediate input gear 74, the second idle gear 76, the first idle gear 75, the first intermediate input gear 73, and the intermediate paper discharge roller gear 79. The intermediate paper discharge roller 63a to which the driving force is transmitted rotates in the reverse rotation direction.

[0072] The drive device 7 includes a first sector gear 81, a second sector gear 82, a switch arm 92, a lever 93, and a solenoid 94. The pendulum gear 72 is configured to be selectively meshed with one of the first intermediate input gear 73 and the second intermediate input gear 74 by the first sector gear 81, the second sector gear 82, the switch arm 92, the lever 93, and the solenoid 94.

[0073] (First sector gear) As shown in FIG. 5, the first sector gear 81 is arranged in a posture in which the rotation axis direction is the left - right direction, and is configured to be rotatable counterclockwise when viewed from the right side. The first sector gear 81 includes a rim 811, a web 812, and a boss 813.

[0074] The rim 811 is formed in a flat cylindrical shape. On the outer peripheral surface of the rim 811, first tooth portions 814A and 814B composed of a large number of gear teeth are formed. The first tooth portions 814A and 814B are arranged along the circumferential direction, and between the first tooth portion 814A and the first tooth portion 814B, tooth - missing portions 815A and 815B where gear teeth are missing are formed. The first tooth portions 814A and 814B are an example of tooth portions that can mesh with a second gear.

[0075] In the rotation direction of the first sector gear 81, the tooth - missing portion 815A is located between the downstream end of the first tooth portion 814A and the upstream end of the first tooth portion 814B, and the tooth - missing portion 815B is located between the upstream end of the first tooth portion 814A and the downstream end of the first tooth portion 814B.

[0076] The web 812 is formed in a substantially annular shape extending from the inner peripheral surface of the rim 811 toward the center of the first sector gear 81. At an intermediate portion in the radial direction of the web 812, an engaging wall portion 816 having a substantially semi - circular arc shape extending to the right is formed. On the engaging wall portion 816, an engaging portion 817 protruding radially outward is formed.

[0077] The web 812 is formed with a long hole 819 located between the engaging wall portion 816 and the rim 811. The long hole 819 penetrates in the left - right direction and extends along the circumferential direction. The boss 813 is formed in a cylindrical shape extending to the right from the inner - peripheral edge of the web 812.

[0078] (Second sector gear) The second sector gear 82 is arranged in a posture where the rotation - axis direction is the left - right direction and is configured to be rotatable counter - clockwise when viewed from the right side. The second sector gear 82 includes a rim 821, a web 822, and a boss 823.

[0079] The rim 821 is formed in a flat - cylindrical shape. On the outer - peripheral surface of the rim 821, second tooth portions 824A, 824B, 824C composed of a large number of gear teeth are formed. The second tooth portions 824A, 824B, 824C are arranged along the circumferential direction and are positioned in the order of the second tooth portion 824A, the second tooth portion 824B, and the second tooth portion 824C from the downstream side to the upstream side in the rotation direction.

[0080] A tooth - missing portion 825A where gear teeth are missing is formed between the second tooth portion 824C and the second tooth portion 824A. A tooth - missing portion 825B where gear teeth are missing is formed between the second tooth portion 824A and the second tooth portion 824B. A tooth - missing portion 825C where gear teeth are missing is formed between the second tooth portion 824B and the second tooth portion 824C.

[0081] The web 822 is formed in a substantially arc shape from the inner - peripheral surface of the rim 821 toward the center of the second sector gear 82. A protrusion 826 protruding to the right is formed at an intermediate portion in the radial direction of the web 822 at a position corresponding to the long hole 819 of the first sector gear 81. The protrusion 826 enters the long hole 819 from the left side. In the rotation direction of the second sector gear 82, the length of the protrusion 826 is formed to be smaller than the length of the long hole 819. The protrusion 826 is movable in the circumferential direction within the range of the length of the long hole 819.

[0082] The boss 823 is formed in a cylindrical shape extending from the inner peripheral edge of the web 822 to both the left and right sides. The outer diameter of the boss 823 is formed smaller than the inner diameter of the boss 813 of the first sector gear 81.

[0083] As shown in FIGS. 2 and 3, the second sector gear 82 includes a cam 827 located on the left side of the web 822. The cam 827 includes a first cam surface 827a, a second cam surface 827b, and a third cam surface 827c.

[0084] The first cam surface 827a extends radially from the boss 823 to the second sector gear 82. One end of the second cam surface 827b is connected to the first cam surface 827a and extends at an acute angle with respect to the first cam surface 827a. The third cam surface 827c is formed across between the boss 823 and the other end of the second cam surface 827b and extends in a direction orthogonal to the direction in which the second cam surface 827b extends.

[0085] The first sector gear 81 and the second sector gear 82 are engaged with play in the rotational direction. Specifically, the rim 821 of the second sector gear 82 is disposed on the left side with respect to the rim 811 of the first sector gear 81, and the boss 823 of the second sector gear 82 is inserted into the boss 813 of the first sector gear 81 from the left side. Also, the protrusion 826 of the second sector gear 82 is inserted into the long hole 819 of the first sector gear 81 from the left side. The second sector gear 82 is relatively rotatable with respect to the first sector gear 81 within a range where the protrusion 826 can move within the long hole 819.

[0086] In a state where the first sector gear 81 and the second sector gear 82 are engaged, the rotational positions of the first tooth portion 814A of the first sector gear 81 and the second tooth portion 824A of the second sector gear 82 are substantially the same. Also, the rotational positions of the first toothless portion 815A of the first sector gear 81 and the second toothless portion 825A of the second sector gear 82 are substantially the same, and the rotational positions of the first toothless portion 815B of the first sector gear 81 and the second toothless portion 825B of the second sector gear 82 are substantially the same. Further, the rotational positions of the first tooth portion 815B of the first sector gear 81 and the second tooth portion 824B, the second toothless portion 825C, and the second tooth portion 824C of the second sector gear 82 are substantially the same.

[0087] (Switch arm) As shown in FIGS. 2 and 3, the switch arm 92 is formed of a plate-like member extending along a direction orthogonal to the left-right direction. The switch arm 92 includes a first bearing 921, a second bearing 922, an opening 923, and a cam contact surface 924.

[0088] The rotation shaft 71a of the drive gear 71 is rotatably inserted into the first bearing 921. By inserting the rotation shaft 71a into the first bearing 921, the switch arm 92 is rotatably supported by the rotation shaft 71a.

[0089] The rotation shaft 72a of the pendulum gear 72 is rotatably inserted into the second bearing 922. By inserting the rotation shaft 72a into the second bearing 922, the pendulum gear 72 is rotatably supported by the switch arm 92. The second bearing 922 is located above the first bearing 921.

[0090] The pendulum gear 72 is movable to a third position where it meshes with the first intermediate input gear 73 and a fourth position where it meshes with the second intermediate input gear 74 when the switch arm 92 rotates about the rotation shaft 71a.

[0091] The opening 923 penetrates the switch arm 92 in the left - right direction. The cam contact surface 924 is formed at the peripheral edge of the opening 923, and the cam 827 of the second sector gear 82 can abut thereon. The cam contact surface 924 is located in front of the first bearing 921.

[0092] The cam contact surface 924 is formed at the lower peripheral edge of the opening 923, and includes a first contact surface 924a, a second contact surface 924b, and a third contact surface 924c. The first contact surface 924a is located at the front end of the cam contact surface 924, the third contact surface 924c is located behind the first contact surface 924a, and the second contact surface 924b is located between the first contact surface 924a and the third contact surface 924c.

[0093] (Lever) As shown in FIGS. 2 - 4 and FIG. 6, the lever 93 includes a boss 931, a first engaging claw 932, a second engaging claw 933, an operation portion 934, and a connecting wall 935.

[0094] The boss 931 is formed in a cylindrical shape extending along the left - right direction. The gear frame 91 includes a support shaft 912 extending along the left - right direction. The support shaft 912 extends leftward from the support wall 911. The support shaft 912 is inserted into the boss 931 of the lever 93. The boss 931 is rotatably supported by the support shaft 912. The lever 93 is rotatable about the support shaft 912. The gear frame 91 is an example of a frame including a support shaft inserted into the boss of the lever.

[0095] The first engaging claw 932 projects radially outward from the boss 931. The first engaging claw 932 can engage with the engaging portion 817 of the first sector gear 81. The radial direction is an example of a direction orthogonal to the axial direction of the conveying roller.

[0096] The second engaging claw 933 protrudes radially outward from the boss 931 in a phase different from the protruding direction of the first engaging claw 932. The second engaging claw 933 can engage with the engaging portion 817 of the first sector gear 81. The first engaging claw 932 and the second engaging claw 933 are an example of engaging claws that can engage with the engaging portion of the sector gear.

[0097] The operating portion 934 protrudes radially outward from the boss 931 in a phase different from the protruding directions of the first engaging claw 932 and the second engaging portion 933. The operating portion 934 can engage with the solenoid 94.

[0098] The operating portion 934 protrudes obliquely upward and rearward from the boss 931, the first engaging claw 932 protrudes obliquely downward and rearward from the boss 931, and the second engaging claw 933 protrudes substantially downward from the boss 931. The operating portion 934 and the first engaging claw 932 are arranged adjacent to each other.

[0099] The connecting wall 935 is a wall member formed across the operating portion 934 and the first engaging claw 932. The connecting wall 935 connects the operating portion 934 and the first engaging claw 932. The boss 931 and the operating portion 934 protrude leftward of the first engaging claw 932 and the second engaging claw 933.

[0100] When the lever 93 rotates about the support shaft 912 and moves to the first position (the position shown in FIG. 8) as the operating portion 934 engageable with the solenoid 94 is pulled by the solenoid 94, and when the pulling of the operating portion 934 by the solenoid 94 is released, the lever 93 rotates about the support shaft 912 and moves to the second position (the position shown in FIG. 7).

[0101] When the lever 93 is in the first position, the second engaging claw 933 is located within the region through which the engaging portion 817 passes due to the rotation of the first sector gear 81, and the first engaging claw 932 is located outside the region through which the engaging portion 817 passes due to the rotation of the first sector gear 81.

[0102] When the lever 93 is in the second position, the first engaging claw 932 is located within the region through which the engaging portion 817 passes due to the rotation of the first sector gear 81, and the second engaging claw 933 is located outside the region through which the engaging portion 817 passes due to the rotation of the first sector gear 81.

[0103] (Solenoid) As shown in FIGS. 2 to 4, the solenoid 94 includes a plunger 941, a coil 942, a case 943, and a biasing spring 944.

[0104] The plunger 941 is movable in the pulling direction in which the solenoid 94 pulls the operating portion 934 of the lever 93. The plunger 941 includes an engaging portion 941a that engages with the operating portion 934 of the lever 93. The operating portion 934 of the lever 93 includes a solenoid contact portion 934a that contacts the engaging portion 941a when the engaging portion 941a of the plunger 941 engages therewith (see FIG. 6). The solenoid contact portion 934a protrudes radially outward from the boss 931.

[0105] The coil 942 has the solenoid 94 movably inserted therein. When the solenoid 94 is turned on and current flows through the coil 942, the plunger 941 is drawn into the coil 942 and pulls the operating portion 934 of the lever 93. When the operating portion 934 is pulled by the plunger 941, the lever 93 moves to the first position.

[0106] When the solenoid 94 is turned off and current no longer flows through the coil 942, the plunger 941 is drawn out of the coil 942, and the pulling state of the operating portion 934 of the lever 93 by the plunger 941 is released. When the pulling state of the operating portion 934 is released, the lever 93 moves to the second position.

[0107] Case 943 covers coil 942. Biasing spring 944 is a coil spring and is disposed between case 943 of solenoid 94 and operating portion 934 of lever 93. Biasing spring 944 biases lever 93 toward the second position side from the first position side. When the pulling state of operating portion 934 by plunger 941 is released from the state where lever 93 is in the first position, lever 93 moves to the second position by the biasing force of biasing spring 944.

[0108] (Biasing member) As shown in FIGS. 2 to 4, drive device 7 includes a first biasing member 83, a second biasing member 84, and a third biasing member 85.

[0109] The first biasing member 83 is a coil spring. One end of the first biasing member 83 is connected to the first sector gear 81, and the other end of the first biasing member 83 is connected to the second sector gear 82. The first biasing member 83 biases the first sector gear 81 in the clockwise direction when viewed from the left side. The first sector gear 81 is rotatable relative to the second sector gear 82 in the clockwise direction when viewed from the left side by the biasing force of the first biasing member 83.

[0110] The second biasing member 84 is a coil spring. Drive device 7 includes a gear cover 95 (see FIG. 11) that covers each of the gears 70 to 79, switch arm 92, lever 93, and solenoid 94 from the left side. Gear cover 95 covers switch arm 92 from the opposite side of support wall 911 in gear frame 91 that sandwiches switch arm 92 in the left - right direction. Switch arm 92 includes a spring support portion 925 located on the front side of the first bearing 921.

[0111] One end of the second biasing member 84 is connected to spring support portion 925 of switch arm 92, and the other end of the second biasing member 84 is connected to gear cover 95. The second biasing member 84 biases the portion of switch arm 92 on the front side of the first bearing 921 upward.

[0112] The third biasing member 85 is a torsion coil spring. The gear frame 91 is provided with a spring engaging portion 913. One end of the third biasing member 85 is engaged with the spring engaging portion 913 of the gear frame 91, and the other end of the third biasing member 85 is in contact with the second sector gear 82. By the third biasing member 85, the second sector gear 82 is biased in the clockwise direction when viewed from the left side.

[0113] [Operation of the driving device] In the driving device 7, with the above configuration, it is possible to switch between a normal rotation mode in which the rotation directions of the paper discharge roller 64a and the intermediate paper discharge roller 63a are the normal rotation directions, and a reverse rotation mode in which the rotation directions of the paper discharge roller 64a and the intermediate paper discharge roller 63a are the reverse rotation directions.

[0114] (Normal rotation mode) As shown in FIG. 7, in the state where the driving device 7 is switched to the normal rotation mode, the first cam surface 827a of the cam 827 of the second sector gear 82 is in contact with the first contact surface 924a of the cam contact surface 924 of the switch arm 92.

[0115] In this case, the switch arm 92 rotates about the rotation axis 71a of the driving gear 71 by the biasing force of the second biasing member 84, and the front end portion of the switch arm 92 is in the state where it is most lifted. In this state, the pendulum gear 72 moves to the third position and meshes with the first intermediate input gear 73.

[0116] Therefore, the driving force input from the input gear 70 to the driving gear 71 is transmitted to the paper discharge roller 64a via the pendulum gear 72, the second intermediate input gear 74, the second idler gear 76, the third idler gear 77, and the paper discharge roller gear 78. The paper discharge roller 64a to which the driving force is transmitted rotates in the reverse rotation direction.

[0117] Also, the driving force input from the input gear 70 to the driving gear 71 is transmitted to the intermediate paper discharge roller 63a via the pendulum gear 72, the first intermediate input gear 73, and the intermediate paper discharge roller gear 79. The intermediate paper discharge roller 63a to which the driving force is transmitted rotates in the normal rotation direction.

[0118] In the forward rotation mode, the solenoid 94 is turned off, and the lever 93 is positioned at the second position where the pulling force by the solenoid 94 is released. As shown in FIG. 7(b), the first engaging claw 932 of the lever 93 positioned at the second position is engaged with the engaging portion 817 of the first sector gear 81, and the counterclockwise rotation as viewed from the right side of the first sector gear 81 is restricted.

[0119] By restricting the rotation of the first sector gear 81, the second sector gear 82 is rotatable within the range where the protrusion 826 that has entered the long hole 819 of the first sector gear 81 can move.

[0120] The second sector gear 82 is biased in the counterclockwise direction as viewed from the right side by the third biasing member 85, and the first biasing member 83 is compressed by the second sector gear 82 biased by the third biasing member 85. The first sector gear 81 is biased in the counterclockwise direction as viewed from the right side by the biasing force of the compressed first biasing member 83, and the engaging state between the engaging portion 817 and the first engaging claw 932 is maintained by this biasing force.

[0121] In the state where the engaging portion 817 is engaged with the first engaging claw 932 of the lever 93, the first toothless portion 815A of the first sector gear 81 and the second toothless portion 825A of the second sector gear 82 are positioned facing the drive gear 71, and the first sector gear 81 and the second sector gear 82 are not meshed with the drive gear 71. In this case, even if the second sector gear 82 rotates within the movable range, the second sector gear 82 is configured not to mesh with the drive gear 71.

[0122] (Switching from the forward rotation mode to the reverse rotation mode) When the drive device 7 is switched from the forward rotation mode to the reverse rotation mode, the solenoid 94 is switched from off to on. As shown in FIG. 8, when the solenoid 94 is switched to on, the operation portion 934 of the lever 93 is pulled by the solenoid 94, and the lever 93 moves from the second position to the first position. When the lever 93 moves to the first position, the engagement between the first engagement claw 932 of the lever 93 and the engagement portion 817 of the first sector gear 81 is released, and the first sector gear 81 becomes rotatable.

[0123] The rotatable first sector gear 81 rotates counterclockwise as viewed from the right by the biasing force of the first biasing member 83. As the first sector gear 81 rotates due to the biasing force of the first biasing member 83, the first tooth portion 814A of the first sector gear 81 and the drive gear 71 start to mesh. After the first tooth portion 814A and the drive gear 71 are meshed, the first sector gear 81 rotates by the driving force from the drive gear 71.

[0124] Also, due to the rotation of the first sector gear 81, the end portion of the long hole 819 of the first sector gear 81 abuts against the protrusion 826 of the second sector gear 82 and presses the protrusion 826 in the rotation direction of the first sector gear 81. Due to this pressing force and the biasing force of the third biasing member 85, the second sector gear 82 rotates clockwise as viewed from the left.

[0125] As the second sector gear 82 rotates, the second tooth portion 824A of the second sector gear 82 and the drive gear 71 start to mesh. After the second tooth portion 824A and the drive gear 71 are meshed, the second sector gear 82 rotates by the driving force from the drive gear 71.

[0126] As the second sector gear 82 rotates, the cam 827 rotates clockwise as viewed from the left. Due to the rotation of the cam 827, the contact mode between the cam 827 and the cam contact surface 924 of the switch arm 92 changes.

[0127] That is, when the cam 827 rotates, the connection portion between the first cam surface 827a and the second cam surface 827b of the cam 827 changes from the mode in which the first cam surface 827a of the cam 827 shown in FIG. 7(a) contacts the first contact surface 924a of the cam contact surface 924 to the mode in which it contacts the second contact surface 924b of the cam contact surface 924.

[0128] When the cam 827 further rotates, as shown in FIG. 8(a), the connection portion between the first cam surface 827a and the second cam surface 827b of the cam 827 changes to the mode in which it contacts the third contact surface 924c of the cam contact surface 924.

[0129] Due to this change in the contact mode, the cam contact surface 924 is pressed downward by the cam 827. When the cam contact surface 924 is pressed downward, the switch arm 92 rotates clockwise as viewed from the left around the rotation axis 71a of the drive gear 71 so that the front end portion of the switch arm 92 moves downward.

[0130] When the switch arm 92 rotates, the pendulum gear 72 moves from the third position to the fourth position, the meshing between the pendulum gear 72 and the first intermediate input gear 73 is released, and the pendulum gear 72 meshes with the second intermediate input gear 74.

[0131] In this case, as shown in FIG. 8(b), when the rotation of the first sector gear 81 and the second sector gear 82 due to the driving force from the drive gear 71 progresses, the first toothless portion 815B of the first sector gear 81 and the second toothless portion 825B of the second sector gear 82 move to the positions facing the drive gear 71. Thereby, the meshing between the first sector gear 81 and the second sector gear 82 and the drive gear 71 is released.

[0132] When the meshing between the first sector gear 81 and the second sector gear 82 and the drive gear 71 is released, the input of the driving force from the drive gear 71 to the first sector gear 81 and the second sector gear 82 is cut off.

[0133] When the input of the driving force from the driving gear 71 stops, the first sector gear 81 and the second sector gear 82 rotate by the biasing force from the third biasing member 85, and stop when the engaging portion 817 of the first sector gear 81 engages with the second engaging claw 933 of the lever 93. When the first sector gear 81 and the second sector gear 82 stop, the state where the first toothless portion 815B and the second toothless portion 825B face the driving gear 71 is maintained.

[0134] Also, after the engaging portion 817 and the second engaging claw 933 engage, the first biasing member 83 is compressed by the biasing force of the third biasing member 85. Thereby, the engaging state between the engaging portion 817 and the second engaging claw 933 is maintained by the biasing force of the first biasing member 83.

[0135] When the engaging portion 817 and the second engaging claw 933 engage, the connecting portion between the first cam surface 827a and the second cam surface 827b of the cam 827 contacts the third contact surface 924c of the cam contact surface 924, and the pendulum gear 72 moves to the fourth position. When the pendulum gear 72 moves to the fourth position, the pendulum gear 72 meshes with the second intermediate input gear 74, and the switching to the reverse mode is completed.

[0136] In the reverse mode, the driving force input from the input gear 70 to the driving gear 71 is transmitted to the paper discharge roller 64a via the pendulum gear 72, the second intermediate input gear 74, the second idle gear 76, the third idle gear 77, and the paper discharge roller gear 78, and the paper discharge roller 64a rotates in the reverse direction.

[0137] Also, the driving force input from the input gear 70 to the driving gear 71 is transmitted to the intermediate paper discharge roller 63a via the pendulum gear 72, the second intermediate input gear 74, the second idle gear 76, the first idle gear 75, the first intermediate input gear 73, and the intermediate paper discharge roller gear 79, and the intermediate paper discharge roller 63a rotates in the reverse direction.

[0138] (Switching from the reverse mode to the forward mode) When switching the drive device 7 from the reverse mode to the forward mode, the solenoid 94 is switched from on to off. As shown in FIG. 7, when the solenoid 94 is switched off, the pulling of the operating portion 934 of the lever 93 by the solenoid 94 is released, and the lever 93 moves from the first position to the second position by the biasing force of the biasing spring 944.

[0139] When the lever 93 moves to the second position, the engagement between the second engaging claw 933 of the lever 93 and the engaging portion 817 of the first sector gear 81 is released, and the first sector gear 81 becomes rotatable.

[0140] The rotatable first sector gear 81 rotates counterclockwise as viewed from the right by the biasing force of the first biasing member 83. As the first sector gear 81 rotates by the biasing force of the first biasing member 83, the first tooth portion 814B of the first sector gear 81 and the drive gear 71 start to mesh. After the first tooth portion 814B and the drive gear 71 are meshed, the first sector gear 81 rotates by the driving force from the drive gear 71.

[0141] Further, due to the rotation of the first sector gear 81, the end portion of the long hole 819 of the first sector gear 81 abuts against the protrusion 826 of the second sector gear 82 and presses the protrusion 826 in the rotation direction of the first sector gear 81. Due to this pressing force and the biasing force of the third biasing member 85, the second sector gear 82 rotates clockwise as viewed from the left.

[0142] As the second sector gear 82 rotates, the second tooth portion 824B of the second sector gear 82 and the drive gear 71 start to mesh. After the second tooth portion 824B and the drive gear 71 are meshed, the second sector gear 82 rotates by the driving force from the drive gear 71.

[0143] As the second sector gear 82 rotates, the cam 827 rotates clockwise as viewed from the left. Due to the rotation of the cam 827, the contact mode between the cam 827 and the cam contact surface 924 of the switch arm 92 changes.

[0144] That is, when the cam 827 rotates, the connection portion between the first cam surface 827a and the second cam surface 827b of the cam 827 shown in FIG. 8(a) comes into contact with the third contact surface 924c of the cam contact surface 924, and then changes to a mode in which the connection portion between the first cam surface 827a and the second cam surface 827b of the cam 827 disengages from the third contact surface 924c of the cam contact surface 924.

[0145] After that, the connection portion between the second cam surface 827b and the third cam surface 827c of the cam 827 passes through a mode in which it contacts the third contact surface 924c of the cam contact surface 924, and then changes to a mode in which the first cam surface 827a of the cam 827 contacts the first contact surface 924a of the cam contact surface 924 as shown in FIG. 7(a).

[0146] Due to this change in the contact mode, the switch arm 92 rotates counterclockwise as viewed from the left around the rotation axis 71a of the drive gear 71 so that the front end portion of the switch arm 92 moves upward by the biasing force of the second biasing member 84.

[0147] When the switch arm 92 rotates, the pendulum gear 72 moves from the fourth position to the third position, the meshing between the pendulum gear 72 and the second intermediate input gear 74 is disengaged, and the pendulum gear 72 meshes with the first intermediate input gear 73.

[0148] In this case, as shown in FIG. 7(b), when the rotation of the first sector gear 81 and the second sector gear 82 due to the driving force from the drive gear 71 progresses, the first toothless portion 815A of the first sector gear 81 and the second toothless portion 825A of the second sector gear 82 move to positions facing the drive gear 71. As a result, the meshing between the first sector gear 81 and the second sector gear 82 and the drive gear 71 is disengaged.

[0149] When the meshing between the first sector gear 81 and the second sector gear 82 and the drive gear 71 is disengaged, the input of the driving force from the drive gear 71 to the first sector gear 81 and the second sector gear 82 is cut off.

[0150] When the input of the driving force from the drive gear 71 stops, the first sector gear 81 and the second sector gear 82 rotate by the biasing force from the third biasing member 85, and stop when the engaging portion 817 of the first sector gear 81 engages with the first engaging claw 932 of the lever 93. When the first sector gear 81 and the second sector gear 82 stop, the state where the first toothless portion 815A and the second toothless portion 825A face the drive gear 71 is maintained.

[0151] Further, after the engaging portion 817 and the first engaging claw 932 engage with each other, the first biasing member 83 is compressed by the biasing force of the third biasing member 85. Thereby, the engaging state between the engaging portion 817 and the first engaging claw 932 is maintained by the biasing force of the first biasing member 83.

[0152] When the engaging portion 817 and the first engaging claw 932 engage with each other, the first cam surface 827a of the cam 827 contacts the first contact surface 924a of the cam contact surface 924, and the pendulum gear 72 moves to the third position. When the pendulum gear 72 moves to the third position, the pendulum gear 72 meshes with the first intermediate input gear 73, and the switching to the forward rotation mode is completed.

[0153] Thus, in the drive device 7, the pendulum gear 72 is movable between a third position where it meshes with the first intermediate input gear 73 and a fourth position where the meshing with the first intermediate input gear 73 is released, in conjunction with the movement of the lever 93 between the first position and the second position. Further, the switch arm 92 that supports the pendulum gear 72 is movable between the third position and the fourth position of the pendulum gear 72 in conjunction with the movement of the lever 93 between the first position and the second position.

[0154] [Support Structure of Lever] As shown in FIG. 9, the lever 93 is rotatably supported by the gear frame 91 by inserting the support shaft 912 of the gear frame 91 into the boss 931.

[0155] The boss 931 includes a large-diameter portion 931a, an intermediate portion 931b, and a small-diameter portion 931c. The large-diameter portion 931a is located on the right side of the boss 931, and the small-diameter portion 931c is located at the left end of the boss 931. The intermediate portion 931b is located between the large-diameter portion 931a and the small-diameter portion 931c in the left-right direction. The intermediate portion 931b is formed with a smaller diameter than the large-diameter portion 931a, and the small-diameter portion 931c is formed with a smaller diameter than the intermediate portion 931b.

[0156] The support shaft 912 includes a large-diameter portion 912a and a small-diameter portion 912b. In the support shaft 912, the large-diameter portion 912a is located at the right end, which is the base side closer to the support wall 911 of the gear frame 91, and the small-diameter portion 912b extends leftward from the large-diameter portion 912a. The large-diameter portion 912a is formed with a larger diameter than the small-diameter portion 912b.

[0157] In the support shaft 912 inserted into the boss 931, the large-diameter portion 912a contacts the right end portion of the large-diameter portion 931a of the boss 931, and the middle portion of the small-diameter portion 912b in the left-right direction contacts the small-diameter portion 931c of the boss 931. The portion between the portion of the support shaft 912 that contacts the large-diameter portion 931a of the boss 931 and the portion that contacts the small-diameter portion 931c of the boss 931 does not contact the inner peripheral surface of the boss 931 and is spaced apart from the inner peripheral surface of the boss 931.

[0158] The portion of the support shaft 912 that contacts the small-diameter portion 931c of the boss 931 is the first contact portion 912A, and the portion that contacts the large-diameter portion 931a of the boss 931 is the second contact portion 912B. The first contact portion 912A and the second contact portion 912B are spaced apart in the left-right direction. The portion between the first contact portion 912A and the second contact portion 912B of the support shaft 912 is a separation portion 912C that is positioned with a gap from the inner peripheral surface of the boss 931. That is, the support shaft 912 supports the boss 931 of the lever 93 by the first contact portion 912A and the second contact portion 912B that are spaced apart in the left-right direction.

[0159] In this way, in the drive device 7, the boss 931 of the lever 93 is supported at two locations, namely the first contact portion 912A and the second contact portion 912B, which sandwich the spaced portion 912C of the support shaft 912. Thereby, compared with the case where the boss 931 of the lever 93 is entirely supported by the outer periphery of the support shaft 912, the frictional force generated between the lever 93 and the support shaft 912 can be reduced. Therefore, even when moving the lever 93 using the solenoid 94 with a small and miniaturized suction force, it is possible to smoothly move the lever 93.

[0160] Also, by supporting the lever 93 with the support shaft 912 of the gear frame 91 which is one part, the positional accuracy of the portion supporting the lever 93 with respect to the lever 93 can be improved compared with the case where the lever 93 is supported across two parts. Thereby, it is possible to suppress the displacement of the position between the lever 93 and the portion supporting the lever 93, reduce the kink during the operation of the lever 93, and smoothly move the lever 93.

[0161] Also, the first contact portion 912A of the support shaft 912 is arranged at a position closer to the tip of the support shaft 912 than the second contact portion 912B. The diameter D2 of the second contact portion 912B is formed larger than the diameter D1 of the first contact portion 912A. Thereby, when inserting the support shaft 912 into the boss 931 from the tip side and assembling the lever 93 and the support shaft 93, it is possible to improve the assemblability of the lever 93 with respect to the support shaft 93.

[0162] Also, the gear frame 91 in which the support shaft 912 for supporting the lever 93 is formed is a gear cover that covers each gear 70 - 79. Therefore, it is not necessary to separately provide the member forming the support shaft 912 from the gear frame 91 which is originally required to cover each gear 70 - 79, and the number of parts can be reduced.

[0163] [Positional relationship between the engaging claw of the lever and the solenoid contact portion and the lever] As shown in FIG. 4, the first engaging claw 932 of the lever 93 can engage with an engaging portion 817 formed on the engaging wall portion 816 of the first sector gear 81. When the first engaging claw 932 is engaged with the engaging portion 817, a rotational force acts on the first engaging claw 932 from the engaging portion 817 of the first sector gear 81. When a force from the first sector gear 81 acts on the first engaging claw 932, a force is also applied to the support shaft 912 that supports the lever 93.

[0164] As shown in FIGS. 9 and 10, the center line CL of the first engaging claw 932 in the left - right direction is located at the left end of the second contact portion 912B of the support shaft 912 in the left - right direction. That is, the left - hand half of the first engaging claw 932 is located between the first contact portion 912A and the second contact portion 912B in the left - right direction, and the first engaging claw 932 has a portion located between the first contact portion 912A and the second contact portion 912B in the left - right direction.

[0165] In this way, since the first engaging claw 932 is located between the first contact portion 912A and the second contact portion 912B in the left - right direction, when a force acting on the first engaging claw 932 is applied to the support shaft 912, it is possible to suppress the force applied to the support shaft 912 from being biased to one of the first contact portion 912A and the second contact portion 912B. Thereby, even when moving the lever 93 using the solenoid 94 with a reduced - size and small suction force, it is possible to smoothly move the lever 93.

[0166] Regarding the second engaging claw 933 of the lever 93 as well, similar to the case of the first engaging claw 932, it is located between the first contact portion 912A and the second contact portion 912B in the left - right direction. Therefore, when a force acting on the second engaging claw 933 is applied to the support shaft 912, it is possible to suppress the force applied to the support shaft 912 from being biased to one of the first contact portion 912A and the second contact portion 912B. Thereby, even when moving the lever 93 using the solenoid 94 with a reduced - size and small suction force, it is possible to smoothly move the lever 93.

[0167] As shown in FIG. 10, the operation portion 934 of the lever 93 can engage with the engagement portion 941a on the plunger 941 of the solenoid 94. When the operation portion 934 and the engagement portion 941a are engaged, the engagement portion 941a contacts the solenoid contact portion 934a of the operation portion 934. When the operation portion 934 engages with the engagement portion 941a and is pulled by the plunger 941, a force in the pulling direction acts on the solenoid contact portion 934a of the operation portion 934.

[0168] When a force from the plunger 941 acts on the solenoid contact portion 934a, a force is also applied to the support shaft 912 that supports the lever 93. The solenoid contact portion 934a of the operation portion 934 is located between the first contact portion 912A and the second contact portion 912B in the left - right direction.

[0169] In this way, since the solenoid contact portion 934a of the operation portion 934 is located between the first contact portion 912A and the second contact portion 912B in the left - right direction, when a force acting on the solenoid contact portion 934a is applied to the support shaft 912, it is possible to suppress the force applied to the support shaft 912 from being biased to one of the first contact portion 912A and the second contact portion 912B. Thereby, even when moving the lever 93 using the solenoid 94 with a small and miniaturized suction force, it is possible to smoothly move the lever 93.

[0170] Also, in the lever 93, the solenoid contact portion 934a is located to the left of the first engagement claw 932 and the second engagement claw 933, but the solenoid contact portion 934a, the first engagement claw 932, and the second engagement claw 933 are all located between the first contact portion 912A and the second contact portion 912B.

[0171] Therefore, even when forces are applied to both the solenoid contact portion 934a and the first engagement claw 932 and the second engagement claw 933, it is possible to suppress the force applied to the support shaft 912 from being biased to one of the first contact portion 912A and the second contact portion 912B. Thereby, even when moving the lever 93 using the solenoid 94 with a small and miniaturized suction force, it is possible to smoothly move the lever 93.

[0172] [Connecting wall of the lever] In lever 93, when a pulling force from solenoid 94 is applied to solenoid contact portion 934a and a rotational force from first sector gear 81 is applied to first engaging claw 932, a force acting in the direction in which operating portion 934 and first engaging claw 932 move apart acts on operating portion 934 and first engaging claw 932.

[0173] However, since operating portion 934 and first engaging claw 932 are connected by connecting wall 935, it is possible to suppress operating portion 934 and first engaging claw 932 from moving apart. Thereby, when operating portion 934 is pulled by solenoid 94 and moves to the first position, the engagement state between first engaging claw 932 and engagement portion 817 of first sector gear 81 can be appropriately released.

[0174] [Fixing of the solenoid to the gear frame] As shown in FIGS. 2 to 4 and FIG. 11, case 943 of solenoid 94 includes case side surface 943a. Case side surface 943a is located on the opposite side of support wall 911 in gear frame 91 that sandwiches coil 942 in the left - right direction. A fastening hole 943b into which screw 96 is inserted is formed in case side surface 943a. Case 943 includes case side surface 943c on the side adjacent to support wall 911 of gear frame 91. Case side surface 943c is located between support wall 911 and coil 942 in the left - right direction.

[0175] Screw 96 is a fastening member for fixing case 943 of solenoid 94 to gear frame 91. As a fastening member for fixing case 943 to gear frame 91, a bolt can also be used.

[0176] The gear frame 91 is provided with a solenoid fixing portion 914 that protrudes leftward from the support wall 911. The solenoid fixing portion 914 is formed with a fixing hole 914a that extends along the left-right direction and into which a screw 96 can be screwed. By screwing the screw 96 into the fixing hole 914a of the solenoid fixing portion 914 with the screw 96 inserted into the fastening hole 943b on the case side surface 943a, the case 943 can be fastened and fixed to the gear frame 91.

[0177] If the fastening hole 943b is formed in the case side surface 943c on the side adjacent to the support wall 911 of the gear frame 91, since the screw 96 protrudes toward the support wall 911 side rather than the solenoid 94, it is necessary to form the fixing hole for screwing the screw 96 to the right of the solenoid 94.

[0178] On the other hand, if the fastening hole 943b is formed in the case side surface 943a on the opposite side of the support wall 911 sandwiching the coil 942, the portion of the screw 96 screwed into the gear frame 91 can be accommodated within the range of the thickness of the solenoid 94 in the left-right direction. Thereby, it is possible to suppress the screw 96 from protruding toward the support wall 911 side rather than the solenoid 94, and it is possible to reduce the size of the apparatus main body 2 in the left-right direction.

[0179] [Arrangement position of the paper discharge roller gear] As shown in FIG. 3, the paper discharge roller gear 78 is arranged at a position overlapping the solenoid 94 in the up-down direction. That is, at least a part of the paper discharge roller gear 78 is located below the upper end of the solenoid 94.

[0180] Thereby, it is possible to reduce the size of the apparatus main body 2 in the up-down direction as compared with the case where the paper discharge roller gear 78 is arranged such that the entire paper discharge roller gear 78 is located above the solenoid 94.

[0181] [Notch of the switch arm] As shown in FIGS. 3 and 12, the switch arm 92 includes a corner portion 926 and a notch 927. The corner portion 926 and the notch 927 are located at an end portion of the switch arm 92 on the rear side of the first bearing 921. In the left-right direction, the notch 927 is formed to the left of the corner portion 926.

[0182] The notch 927 is formed by cutting out a part of the switch arm 92 in the left-right direction. Specifically, a gear cover 95 (see FIG. 11) that covers the switch arm 92 from the left side is located to the left of the switch arm 92, and the notch 927 is formed by cutting out a part of the switch arm 92 on the gear cover 95 side in the left-right direction. By forming the notch 927, the corner portion 926 is located further to the right than the left end of the switch arm 92.

[0183] By providing the switch arm 92 with the notch 927 that cuts out a part of the switch arm 92 on the gear cover 95 side in the left-right direction, it is possible to suppress interference between the switch arm 92 and the gear cover 95, and the operation of the switch arm 92 is not hindered by the gear cover 95.

Explanation of Signs

[0184] 1 Image forming apparatus 2 Housing 7 Driving device 63a Intermediate paper discharge roller 64a Paper discharge roller 71 Driving gear (second gear) 72 Pendulum gear 73 First intermediate input gear (first gear) 78 Paper discharge roller gear 81 First sector gear 91 Gear frame 92 Switch arm 93 Lever 94 Solenoid 95 Gear cover 96 Screw 814A, 814B First tooth portion 817 Engagement portion 911 support wall 912 support shaft 912A first contact portion 912B second contact portion 912C separation portion 927 notch 931 boss 932 first engaging claw 933 second engaging claw 934 operation portion 934a solenoid contact portion 935 connecting wall 941 plunger 942 coil 943 case 943a case side surface 943b fastening hole D1 (diameter of the first contact portion) D2 (diameter of the second contact portion)

Claims

1. A conveying roller extending in the axial direction, A solenoid, A lever engaging with the solenoid, which is movable between a first position pulled by the solenoid and a second position where the pulling by the solenoid is released, and includes a boss protruding in the axial direction, A first gear for transmitting a driving force to the conveying roller, A pendulum gear that is movable in conjunction with the movement of the lever between a third position meshing with the first gear and a fourth position where the meshing with the first gear is released, A frame extending along the axial direction and including a support shaft inserted into the boss of the lever, Comprising, The support shaft includes a first contact portion contacting the boss of the lever, a second contact portion spaced from the first contact portion in the axial direction and contacting the boss of the lever, and a separation portion positioned with a gap from the inner peripheral surface of the boss between the first contact portion and the second contact portion. A driving device.

2. The lever includes a solenoid contact portion contacted by the solenoid, The solenoid contact portion is positioned between the first contact portion and the second contact portion in the axial direction. The driving device according to Claim 1.

3. A second gear to which a driving force is input, A sector gear including a tooth portion engageable with the second gear and an engaging portion engageable with the lever, The lever includes a solenoid contact portion contacted by the solenoid and an engaging claw engageable with the engaging portion of the sector gear, The engaging claw of the lever is positioned between the first contact portion and the second contact portion in the axial direction. The driving device according to Claim 1.

4. The solenoid contact portion of the lever protrudes in a direction orthogonal to the axial direction from the boss, The engaging claw of the lever protrudes in a direction orthogonal to the axial direction from the boss at a phase different from that of the solenoid contact portion, The lever includes a connecting wall connecting the solenoid contact portion and the engaging claw. The driving device according to Claim 3.

5. The solenoid includes a plunger movable in the pulling direction of the lever, a coil into which the plunger is movably inserted, and a case covering the coil, The case includes a case side surface positioned on the opposite side of the frame sandwiching the coil in the axial direction. The drive device according to claim 1 or claim 2, wherein a fastening hole into which a fastening member for fixing the case to the frame is inserted is formed in the case side surface.

6. It includes an output gear to which the driving force from the first gear is transmitted and which is connected to the conveying roller, The drive device according to claim 1 or claim 2, wherein the output gear is located at a position overlapping the solenoid in the vertical direction.

7. A switch arm that supports the pendulum gear and moves the pendulum gear between the third position and the fourth position in conjunction with the movement of the lever, A cover that covers the switch arm from the opposite side of the frame that sandwiches the switch arm in the axial direction, Comprising, The drive device according to claim 1 or claim 2, wherein the switch arm has a notch formed by cutting out a part on the cover side in the axial direction.

8. The drive device according to claim 1 or claim 2, wherein the frame is a gear cover that covers the first gear and the pendulum gear.

9. The first contact portion is arranged at a position closer to the tip of the support shaft than the second contact portion, The drive device according to claim 1 or claim 2, wherein the diameter of the second contact portion is larger than the diameter of the first contact portion.

Images