Sheet separation device

Abstract

A sheet separation device includes a separation roller, a separation pad facing the separation roller, a pad holder, a biasing member that biases the pad holder, and a first frame that swingably supports the pad holder. The pad holder is swingable to a first position in which the separation pad is pressed toward the separation roller, a second position in which the separation roller is separated from the separation pad, and a holding position between the first position and the second position. The pad holder is detachable from the first frame when in the second position. When the pad holder swings between the first or second position and the holding position, the biasing member biases the pad holder to swing toward the second position, and when the pad holder reaches the holding position, the biasing member biases the pad holder to hold the pad holder at the holding position.

Description

REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from Japanese Patent Application No. 2025-054168 filed on Mar. 27, 2025. The entire content of the priority application is incorporated herein by reference.BACKGROUND ART

[0002] The present disclosure relates to a sheet separation device.

[0003] There is known a sheet feeding mechanism as an example of a conventional sheet separation device. In this sheet feeding mechanism, a separation roller conveys a sheet in a conveyance direction. A separation pad faces the separation roller and separates sheets conveyed by the separation roller. A pad holder holds the separation pad. A torsion spring biases the pad holder toward the separation roller. A unit case swingably supports the pad holder.

[0004] The pad holder is swingable between a contact position at which the separation pad is pressed toward the separation roller, and an upright position at which the separation roller is separated from the separation pad and the pad holder stands so that a swinging tip of the pad holder is located upstream in the conveyance direction relative to the contact position. The torsion spring biases the pad holder to swing toward the upright position. The pad holder is detachable from the unit case when in the upright position.SUMMARY

[0005] However, in the conventional sheet feeding mechanism described above, the pad holder biased by the torsion spring may swing from the upright position to a side opposite from the contact position. In this case, the problem is that the pad holder may take an abnormal posture in which the separation pad faces downward, and if the separation roller is installed in this state, the separation roller cannot convey sheets.

[0006] At least one aspect of the present disclosure is advantageous to provide a sheet separation device capable of suppressing the pad holder from swinging to an unintended position at the time of attachment of the pad holder, thereby making it less likely that a failure occurs in which the separation roller cannot convey sheets.

[0007] According to an aspect of the present disclosure, there is provided a sheet separation device including a separation roller configured to convey a sheet in a conveyance direction, a separation pad facing the separation roller and configured to separate sheets conveyed by the separation roller, a pad holder configured to hold the separation pad, a biasing member configured to bias the pad holder toward the separation roller, and a first frame configured to support the pad holder so as to be swingable about a swing axis. The pad holder is swingable to a first position in which the separation pad is pressed toward the separation roller, a second position in which the separation roller is separated from the separation pad and a swinging tip of the pad holder stands so as to be located upstream in the conveyance direction relative to the first position, and a holding position between the first position and the second position. The pad holder is detachable from the first frame when in the second position. When the pad holder swings between the first position and the holding position and when the pad holder swings between the holding position and the second position, the biasing member biases the pad holder so as to swing toward the second position, and when the pad holder reaches the holding position from the first position or the second position, the biasing member biases the pad holder so as to hold the pad holder at the holding position.BRIEF DESCRIPTION OF DRAWINGS

[0008] FIG. 1 is a schematic partial cross-sectional view of an image forming apparatus according to an embodiment, mainly illustrating a state in which a support plate of a deployed feed tray is separated downward from a feed roller.

[0009] FIG. 2 is a schematic partial cross-sectional view similar to FIG. 1, mainly illustrating a state in which the support plate of the deployed feed tray is raised.

[0010] FIG. 3 is a perspective view illustrating a first frame, a second frame, a roller holder, elevating arms, and the like.

[0011] FIG. 4 is a perspective view illustrating the first frame, a feed guide, a separation pad, a pad holder, the elevating arms, and the like.

[0012] FIG. 5 is a partial cross-sectional view illustrating the first frame, the feed guide, the separation pad, the pad holder, a torsion coil spring, and the like, showing a state in which the pad holder is at a first position.

[0013] FIG. 6 is a partial perspective view illustrating a state in which the roller holder is removed from the second frame.

[0014] FIG. 7 is a partial perspective view illustrating a state in which the separation pad and the pad holder are removed from the first frame.

[0015] FIG. 8 is a perspective view of the pad holder.

[0016] FIG. 9 is a partial cross-sectional view similar to FIG. 5, showing a state in which the pad holder is at a holding position.

[0017] FIG. 10 is a partial cross-sectional view similar to FIG. 5, showing a state in which the pad holder is at a second position.

[0018] FIG. 11 is a partial cross-sectional view similar to FIG. 5, illustrating an operation for attaching and detaching the pad holder to and from the first frame.

[0019] FIG. 12 is a schematic diagram illustrating a state in which the pad holder that has reached the holding position receives a biasing force from the biasing member.DESCRIPTION

[0020] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0021] An image forming apparatus 1 according to an embodiment shown in FIG. 1 is an example of a specific aspect of the sheet separation device of the present disclosure. In FIG. 1, a front face 9S side of a housing 9 is defined as the front of the apparatus, and the upper surface side of the housing 9 is defined as the upper side of the apparatus. The width direction of the image forming apparatus 1 is a direction orthogonal to a front-rear direction and an up-down direction. When facing the front face 9S of an apparatus main body (housing) 9, the left side, that is, the near side in FIG. 1, is defined as one side in the width direction. The front-rear direction, the up-down direction, and the width direction shown in FIG. 2 and the subsequent figures are all labeled to correspond to FIG. 1.

[0022] As shown in FIG. 1, the image forming apparatus 1 includes the housing 9, a sheet feeding cassette 2C, an image forming engine 2, and a conveyor (not shown). The housing 9 is substantially box-shaped and has a discharge tray 9T on an upper surface thereof. The sheet feeding cassette 2C is located in a lower portion inside the housing 9 and stores a plurality of sheets in a stacked state.

[0023] The image forming engine 2 is located in an upper portion inside the housing 9. The image forming engine 2 forms an image on a sheet by a general image forming method such as an electrophotographic method, a thermal method, an inkjet method, or the like.

[0024] The conveyor (not shown) supplies sheets one by one from the sheet feeding cassette 2C to the image forming engine 2. The image forming engine 2 forms an image on the sheet. Then, the conveyor (not shown) conveys the sheet on which the image has been formed and discharges the sheet to the discharge tray 9T.Feed Tray

[0025] As shown in FIG. 1, the image forming apparatus 1 includes a feed tray 3. The feed tray 3 is a multipurpose tray for feeding a plurality of types of sheets SH having different sizes, thicknesses, and the like to the image forming engine 2.

[0026] The feed tray 3 is located on the front face 9S side of the housing 9 and is deployed to extend forward from the front face 9S. Although not shown, the feed tray 3 is stowed in the housing 9 by pivoting upward and rearward to stand upright so that the feed tray 3 is aligned with the front face 9S of the housing 9.

[0027] An upward-facing surface of the deployed feed tray 3 is a support surface 3A capable of supporting the sheets SH. A conveyance direction DT1 in which the sheets SH supported on the support surface 3A are conveyed toward the image forming engine 2 is a rearward direction along the front-rear direction and is a direction orthogonal to the width direction. The feed tray 3 includes a feed tray main body 30, a support plate 31, and a sub-tray 30E.

[0028] The feed tray main body 30 is supported by the housing 9 so as to be pivotable. In a state where the feed tray 3 is deployed, the feed tray main body 30 extends from the front face 9S so as to be inclined upward toward an upstream side in the conveyance direction DT1.

[0029] The support plate 31 is located on an upward-facing surface side of the feed tray main body 30. The support plate 31 is supported by the feed tray main body 30 so as to be pivotable about an axis X31. The axis X31 extends in the width direction at an upstream end side of the support plate 31 in the conveyance direction DT1. As shown in FIGS. 1 and 2, the support plate 31 moves up and down by operation of elevating arms 6L and 6R described later.

[0030] The sub-tray 30E is pulled out from the feed tray main body 30 and extends so as to be inclined upward toward the upstream side in the conveyance direction DT1.

[0031] The support surface 3A is formed by an upward-facing surface of the support plate 31, an upward-facing surface of the sub-tray 30E, and the upward-facing surface of the feed tray main body 30 between the support plate 31 and the sub-tray 30E. A downstream end 3D of the support surface 3A in the conveyance direction DT1 is a downstream end of the support plate 31 in the conveyance direction DT1.First Frame, Feed Guide, Second Frame, and Gear Frame

[0032] As shown in FIGS. 1 and 3, the image forming apparatus 1 includes a first frame 90, a feed guide 89, and a second frame 29, which are located forward of the image forming engine 2. In the present embodiment, the first frame 90, the feed guide 89, and the second frame 29 are each a resin molded product manufactured by, for example, injection molding of a thermoplastic resin. The feed guide 89 and the first frame 90 are located below the second frame 29.

[0033] As shown in FIG. 4, the first frame 90 and the feed guide 89 extend in the width direction. As shown in FIGS. 4 and 5, the feed guide 89 is assembled to the first frame 90 from above to cover an upper portion of the first frame 90 and also cover an upper side of a front portion of the first frame 90.

[0034] The feed guide 89 includes a restricting surface 89A and a feed surface 89B. The restricting surface 89A is a forward-facing surface extending in the width direction. The restricting surface 89A is inclined such that an upper end thereof is positioned rearward of a lower end thereof. The feed surface 89B is an upward-facing surface connected to the upper end of the restricting surface 89A. The feed surface 89B extends so as to be inclined upward toward the downstream side in the conveyance direction DT1.

[0035] As shown in FIG. 1, the restricting surface 89A faces the downstream end 3D of the support surface 3A from the downstream side in the conveyance direction DT1. With the support plate 31 lowered, the restricting surface 89A abuts against and stops a downstream end in the conveyance direction DT1 of the sheet SH supported on the support surface 3A.

[0036] As shown in FIG. 4, the first frame 90 includes coupling sections 99L and 99R on upper end sides of portions located outside in the width direction relative to the feed surface 89B of the feed guide 89.

[0037] As shown in FIG. 3, the second frame 29 also extends in the width direction. One end of the second frame 29 in the width direction is coupled to the coupling section 99L, and the other end of the second frame 29 in the width direction is coupled to the coupling section 99R.

[0038] As shown in FIGS. 3 and 4, the image forming apparatus 1 includes a gear frame 80. In the present embodiment, similarly to the first frame 90 and the like, the gear frame 80 is a resin molded product manufactured by, for example, injection molding of a thermoplastic resin. The gear frame 80 is coupled to one end section 90L of the first frame 90 that is located on one side in the width direction.

[0039] The gear frame 80 is coupled to a side frame (not shown) located on one side surface side of the housing 9 in the width direction. The other end section 90R of the first frame 90 located on the other side in the width direction is coupled to another side frame (not shown) located on the other side surface side of the housing 9 in the width direction. The first frame 90 and the gear frame 80 constitute a reinforcing frame that extends like a beam in the width direction and is supported at both ends, thereby forming a part of an internal frame of the housing 9.Elevating Arms

[0040] The image forming apparatus 1 includes elevating arms 6L and 6R, and a driving force transmission mechanism (not shown) that transmits driving force to the elevating arms 6L and 6R.

[0041] The first frame 90 swingably supports the elevating arm 6L on the one end section 90L side, and swingably supports the elevating arm 6R on the other end section 90R side. The elevating arms 6L and 6R move distal ends thereof up and down by swinging.

[0042] The driving force transmission mechanism (not shown) includes a transmission gear group composed of a plurality of gears supported by the gear frame 80, an electromagnetic clutch, a transmission shaft supported by the first frame 90, a transmission gear, and the like.

[0043] Although not shown, the elevating arms 6L and 6R are in contact from below with pressed portions formed on a downstream end side of the support plate 31 in the conveyance direction DT1. The elevating arms 6L and 6R move the support plate 31 up and down when driving force is transmitted by the driving force transmission mechanism (not shown).Roller Holder, Feed Roller, and Separation Roller

[0044] As shown in FIG. 1, the image forming apparatus 1 includes a roller holder 28, a feed roller 21, and a separation roller 22.

[0045] As shown in FIGS. 3 and 6, the second frame 29 includes an opening 29H and a lock lever 29L.

[0046] The opening 29H is located at a center of the second frame 29 in the width direction. The opening 29H has a substantially rectangular shape in a top view and penetrates the second frame 29 in the up-down direction. The lock lever 29L is located on the other side in the width direction with respect to the opening 29H, and is swingably supported by the second frame 29.

[0047] The second frame 29 detachably supports the roller holder 28. The roller holder 28 is mounted to the second frame 29 by being fitted into the opening 29H and being locked by the lock lever 29L laid down.

[0048] When the user raises the lock lever 29L as indicated by an arrow Y1, the lock lever 29L releases the lock of the roller holder 28. Thus, the user can remove the roller holder 28 from the second frame 29. Also, the user can mount the roller holder 28 to the second frame 29 by performing a reverse operation.

[0049] As shown in FIG. 1, the roller holder 28 rotatably supports the feed roller 21 and the separation roller 22. That is, the feed roller 21 and the separation roller 22 can be attached to and detached from the second frame 29 together with the roller holder 28.

[0050] Lower portions of the feed roller 21 and the separation roller 22 are exposed below the second frame 29. The feed roller 21 is located above the support surface 3A and upstream in the conveyance direction DT1 relative to the downstream end 3D of the support surface 3A. The separation roller 22 is located above the feed surface 89B and downstream in the conveyance direction DT1 relative to the downstream end 3D of the support surface 3A. That is, the feed roller 21 is located upstream in the conveyance direction DT1 relative to the separation roller 22.Pad Holder, Separation Pad, and Torsion Coil Spring

[0051] The image forming apparatus 1 includes a pad holder 40, a separation pad 23, and a torsion coil spring 25.

[0052] As shown in FIGS. 4, 5, and 7, a rectangular hole 89H for exposing the pad holder 40 and the separation pad 23 is formed in a center of the feed surface 89B of the feed guide 89 in the width direction.

[0053] As shown in FIG. 7, the first frame 90 includes a pair of support walls 96. The support walls 96 are spaced apart from each other in the width direction. An upper edge of the support wall 96 located on one side in the width direction is adjacent to an inner peripheral edge of the rectangular hole 89H located on one side in the width direction. An upper edge of the support wall 96 located on the other side in the width direction is adjacent to an inner peripheral edge of the rectangular hole 89H located on the other side in the width direction.

[0054] Each support wall 96 includes a holder support shaft 94. Each holder support shaft 94 projects inward in the width direction from a portion located forward and upward on each support wall 96. Each holder support shaft 94 is a shaft having a substantially oblong cross-sectional shape about a swing axis X40 extending in the width direction.

[0055] As shown in FIG. 8, the pad holder 40 has a substantially rectangular flat-plate shape having a pair of long sides extending parallel to the swing axis X40 and a pair of short sides extending in a direction orthogonal to the swing axis X40. In the present embodiment, the pad holder 40 is a resin molded product manufactured by, for example, injection molding of a thermoplastic resin.

[0056] The pad holder 40 includes a pair of supported sections 49. Each supported section 49 is formed at each end side of the long side of the pad holder 40 located on the swing axis X40 side. Each supported section 49 is formed by cutting away a portion of a circular hole centered on the swing axis X40.

[0057] When the holder support shafts 94 are inserted into the respective supported sections 49, the support walls 96 of the first frame 90 swingably support the pad holder 40 about the swing axis X40 as shown in FIGS. 5 and 9 to 11.

[0058] In FIG. 11, a cross section of a portion of the pad holder 40 located below an imaginary line K1 is a cross section including the supported section 49 located on the other side in the width direction, and differs from the cross section of the pad holder 40 shown in FIGS. 5, 9, and 10. A minimum width of each holder support shaft 94 is a width of each holder support shaft 94 in the up-down direction. An inner width of the cutout of each supported section 49 is set slightly larger than the minimum width of each holder support shaft 94.

[0059] As shown in FIGS. 4 and 5, the pad holder 40 includes an opposing surface 40F. The separation pad 23 is a plate-like member. The separation pad 23 is held by the pad holder 40 by being attached to the opposing surface 40F with, for example, double-sided tape.

[0060] The separation pad 23 is made of a material having a friction coefficient smaller than a friction coefficient of a material forming a surface of the separation roller 22, such as natural rubber, synthetic rubber, cork, urethane, or the like.

[0061] As shown in FIGS. 5 and 8, the pad holder 40 includes a rear surface 40B. The rear surface 40B is a surface facing a side opposite from the opposing surface 40F.

[0062] As shown in FIG. 8, the pad holder 40 includes two ribs 47. Each rib 47 projects from the rear surface 40B, on a side opposite from the opposing surface 40F, in a circumferential direction of the swing axis X40, and extends in a radial direction of the swing axis X40. Also, as shown in FIG. 5, when the pad holder 40 is supported by the first frame 90, the pad holder 40 has the separation pad 23 on an upward-facing surface thereof, and the rear surface 40B on a downward-facing surface thereof has the two ribs 47. Each rib 47 projects downward from the rear surface 40B and extends in the front-rear direction along the rear surface 40B. As shown in FIG. 8, the ribs 47 are located at approximately a center of the rear surface 40B in the width direction and are spaced apart from each other in the width direction.

[0063] A swinging tip 40E of the pad holder 40 is a long side of the pad holder 40 that is far from the swing axis X40. Each rib 47 extends in the radial direction of the swing axis X40 from a position intersecting the swing axis X40 to the swinging tip 40E of the pad holder 40.

[0064] The ribs 47 reinforce the pad holder 40. A rib 47C located between the ribs 47 also reinforces the pad holder 40 together with the ribs 47.

[0065] The pad holder 40 includes first sliding contact sections 41, second sliding contact sections 42, and third sliding contact sections 43. The first sliding contact sections 41, the second sliding contact sections 42, and the third sliding contact sections 43 are formed on distal edges of the ribs 47 that are spaced from the rear surface 40B in the circumferential direction of the swing axis X40. That is, the first sliding contact sections 41, the second sliding contact sections 42, and the third sliding contact sections 43 are located on a side opposite from the opposing surface 40F.

[0066] As shown in FIGS. 8 and 12, with the first frame 90 supporting the pad holder 40, the first sliding contact sections 41 extend linearly forward from a vicinity of the swinging tip 40E of the pad holder 40. Each first sliding contact section 41 extends to a middle portion of each rib 47 in the front-rear direction. Note that, as shown in FIG. 5, in a state where the pad holder 40 is supported by the first frame 90 and the separation roller 22 and the separation pad 23 are in contact with each other, the first sliding contact section 41 of each rib 47 has a shape inclined such that a front end thereof is located lower than a rear end thereof.

[0067] As shown in FIG. 8, each second sliding contact section 42 is located closer to the swing axis X40 than the first sliding contact section 41 and extends substantially linearly forward. Each second sliding contact section 42 extends from a middle portion of each rib 47 in the front-rear direction to a vicinity of the swing axis X40. Note that, as shown in FIG. 5, in a state where the pad holder 40 is supported by the first frame 90 and the separation roller 22 and the separation pad 23 are in contact with each other, the second sliding contact section 42 of each rib 47 has a shape inclined such that a front end thereof is located lower than a rear end thereof.

[0068] As shown in FIG. 12, a distance between the first sliding contact section 41 and the rear surface 40B is defined as distance L1. A distance between the second sliding contact section 42 and the rear surface 40B is defined as distance L2. The distance L2 is greater than the distance L1. That is, a projecting length of a portion of each rib 47 on which the first sliding contact section 41 is formed is smaller than a projecting length of a portion of each rib 47 on which the second sliding contact section 42 is formed.

[0069] As shown in FIGS. 8 and 12, each third sliding contact section 43 is located between the first sliding contact section 41 and the second sliding contact section 42 and extends substantially linearly along the circumferential direction of the swing axis X40. One end 43A of the third sliding contact section 43 that is close to the rear surface 40B is connected to the first sliding contact section 41. The other end 43B of the third sliding contact section 43 that is far from the rear surface 40B is curved in a substantially “quarter arc” shape and connected to the second sliding contact section 42. Accordingly, each rib 47 has a stepped shape having the third sliding contact section 43 at an intermediate position in the front-rear direction. As shown in FIG. 5, in a state where the pad holder 40 is supported by the first frame 90 and the separation roller 22 and the separation pad 23 are in contact with each other, each rib 47 is inclined such that one end 43A of the third sliding contact section 43 is positioned above and forward of the other end 43B, and the inclination direction of the third sliding contact section 43 differs from the inclination direction of the first sliding contact section 41 and the second sliding contact section 42.

[0070] As shown in FIG. 12, a distance from the swing axis X40 to one end 43A of the third sliding contact section 43 is defined as distance L3A. A distance from the swing axis X40 to the other end 43B of the third sliding contact section 43 is defined as distance L3B. The distance L3B is slightly greater than the distance L3A.

[0071] As shown in FIGS. 5 and 8, the pad holder 40 includes a projecting section 48. The projecting section 48 projects from a center of the long side of the pad holder 40 located on the swing axis X40 side toward a side opposite from the opposing surface 40F. The projecting section 48 is a plate-like piece having a tapered shape in a side view.

[0072] As shown in FIGS. 5 and 7, the feed guide 89 includes a hook 89F. The hook 89F is located at a position slightly spaced downward from a center in the width direction of an inner peripheral edge, on a front side of the rectangular hole 89H, and projects rearward in a cantilever-beam shape. A rear end portion of the hook 89F has a hook-claw shape with a claw facing upward.

[0073] As shown in FIGS. 9 and 10, the hook 89F is positioned to interfere with the projecting section 48 when the pad holder 40 swings. The projecting section 48 rides over the hook 89F by bending the hook 89F downward.

[0074] As shown in FIG. 7, the first frame 90 includes, between the support walls 96, a pair of spring support shafts 95C and a pair of spring engagement recesses 95B.

[0075] The spring support shafts 95C are located rearward of the holder support shafts 94 and inward of the holder support shafts 94 in the width direction. Each spring support shaft 95C is a cylindrical projection projecting outward in the width direction. Each spring engagement recess 95B is located rearward of the spring support shaft 95C and is recessed downward.

[0076] The torsion coil spring 25 includes a pair of coil sections 25C, a pair of engaging arms 25B, and a movable arm 25A.

[0077] The coil sections 25C are spaced apart from each other in the width direction. Each coil section 25C is wound around a coil center C1 that is parallel to the swing axis X40. The engaging arms 25B extend rearward from respective coil sections 25C.

[0078] The movable arm 25A is bent into a substantially “U” shape, and a bottom portion of the “U” is a distal end 25A1. The movable arm 25A extends from the coil sections 25C to the distal end 25A1. The distal end 25A1 of the movable arm 25A extends substantially linearly in the width direction.

[0079] Each coil section 25C is fitted onto the spring support shaft 95C, and the engaging arms 25B engage with respective spring engagement recesses 95B. Thus, the torsion coil spring 25 is held by the first frame 90. As shown in FIG. 11, the coil center C1 is located downstream in the conveyance direction DT1 relative to the swing axis X40 and below the swing axis X40.

[0080] FIGS. 7 and 11 illustrate a natural length state in which the torsion coil spring 25 is not loaded. In this state, the movable arm 25A extends upward and slightly forward, and the distal end 25A1 is located upstream in the conveyance direction DT1 relative to the coil center C1.

[0081] The pad holder 40 is swingable to a first position shown in FIGS. 1, 2, and 4 to 6, a second position shown in FIG. 10, and a holding position shown in FIGS. 9 and 12. A position of the pad holder 40 shown by a two-dot chain line in FIG. 11 is also the second position. As shown in FIG. 9, the holding position is located between the first position and the second position.

[0082] As shown in FIG. 5, when the pad holder 40 swings to the first position, the pad holder 40 tilts such that the swinging tip 40E is located downstream in the conveyance direction DT1 relative to the swing axis X40.

[0083] As shown in FIG. 10, when the pad holder 40 swings to the second position, the pad holder 40 stands such that the separation roller 22 is separated from the separation pad 23 and the swinging tip 40E is located upstream in the conveyance direction DT1 relative to the first position. In this state, the swinging tip 40E is located substantially directly above the swing axis X40.

[0084] As shown in FIG. 11, when the pad holder 40 is at the second position, the cutouts of the supported sections 49 of the pad holder 40 are open rearward, thereby making it possible to make the holder support shaft 94 pass therethrough. That is, the pad holder 40 is attachable to and detachable from the first frame 90 when in the second position.

[0085] As shown in FIG. 5, when the pad holder 40 swings between the first position and the holding position, the first sliding contact sections 41 slidably contact the distal end 25A1 of the movable arm 25A of the torsion coil spring 25, thereby receiving from the torsion coil spring 25 a first biasing force F1 that makes the pad holder 40 swing toward the second position.

[0086] As shown in FIG. 10, when the pad holder 40 swings between the holding position and the second position, the second sliding contact sections 42 slidably contact the distal end 25A1 of the movable arm 25A of the torsion coil spring 25, thereby receiving the first biasing force F1 from the torsion coil spring 25. When the pad holder 40 swings to the second position, the torsion coil spring 25 returns to the natural length state, and the first biasing force F1 becomes zero.

[0087] That is, when the pad holder 40 swings between the first position and the holding position and when the pad holder 40 swings between the holding position and the second position, the torsion coil spring 25 biases the pad holder 40 so as to swing toward the second position.

[0088] As shown in FIG. 9, when the pad holder 40 reaches the holding position from the first position or the second position, the third sliding contact sections 43 slidably contact the distal end 25A1 of the movable arm 25A of the torsion coil spring 25 which is caught on the third sliding contact sections 43, thereby receiving from the torsion coil spring 25 a second biasing force F2 that holds the pad holder 40 at the holding position. At this time, as shown in FIG. 12, because the distance L3B is slightly greater than the distance L3A, the distal end 25A1 of the movable arm 25A caught on the third sliding contact sections 43 tends to move from the other ends 43B toward the one ends 43A of the third sliding contact sections 43. The second biasing force F2 is a force component, among force FF2 acting on the pad holder 40 from the distal end 25A1 caught on the third sliding contact sections 43, that acts toward the swing axis X40.

[0089] That is, when the pad holder 40 reaches the holding position from the first position or the second position, the torsion coil spring 25 biases the pad holder 40 so as to hold the pad holder 40 at the holding position.

[0090] When the pad holder 40 swings from the first position to the second position, the distal end 25A1 of the movable arm 25A moves upstream in the conveyance direction DT1 while sliding in contact with the first sliding contact sections 41, the third sliding contact sections 43, and the second sliding contact sections 42 of the pad holder 40.

[0091] When the pad holder 40 swings from the second position to the first position, the distal end 25A1 of the movable arm 25A moves downstream in the conveyance direction DT1 while sliding in contact with the second sliding contact sections 42, the third sliding contact sections 43, and the first sliding contact sections 41 of the pad holder 40.

[0092] As shown in FIG. 9, in a state where the torsion coil spring 25 biases the pad holder 40 so as to hold the pad holder 40 at the holding position, the hook 89F stops the projecting section 48 from the rear. That is, the hook 89F and the projecting section 48 also act to hold the pad holder 40 at the holding position. When the pad holder 40 passes through the holding position, the projecting section 48 rides over the hook 89F by bending the hook 89F downward.

[0093] A position of the pad holder 40 shown by a two-dot chain line in FIGS. 5 and 10 is an abnormal position that the pad holder reaches as the pad holder 40 swings from the second position to a side opposite from the first position.State Where Pad Holder Is at First Position

[0094] As shown in FIG. 5, when the feed roller 21 and the separation roller 22 are mounted to the second frame 29 together with the roller holder 28, the pad holder 40 is pushed by the separation roller 22 and swings to the first position.

[0095] In the state where the pad holder 40 is at the first position, the separation pad 23 and the opposing surface 40F face the separation roller 22 from below. In this state, the torsion coil spring 25 biases the pad holder 40 toward the separation roller 22 by bringing the distal end 25A1 of the movable arm 25A, which has moved downstream in the conveyance direction DT1 relative to the coil center C1, into contact with the first sliding contact sections 41.

[0096] That is, by swinging to the first position, the pad holder 40 brings the separation pad 23 into a state pressed toward the separation roller 22.Image Forming Operation on Sheet Supported on Feed Tray

[0097] When forming an image on the sheet SH supported on the feed tray 3, the elevating arms 6L and 6R raise their distal ends. Thus, as shown in FIG. 3, the support plate 31 rises and the feed roller 21 contacts an uppermost sheet SH supported on the support surface 3A. In this state, the feed roller 21 rotates to feed the uppermost sheet SH toward the separation roller 22 in the conveyance direction DT1. The feed surface 89B guides the sheet SH fed by the feed roller 21.

[0098] The separation roller 22 conveys the sheet SH fed by the feed roller 21 in the conveyance direction DT1. At this time, the separation roller 22 and the separation pad 23 separate the fed sheets SH one by one if a plurality of sheets SH are fed. The image forming engine 2 forms an image on the sheet SH conveyed by the separation roller 22. Thereafter, a conveyor (not shown) conveys the sheet SH on which the image has been formed and discharges the sheet SH to the discharge tray 9T. When the image forming operation ends, the elevating arms 6L and 6R lower their distal ends. Thus, as shown in FIG. 1, the support plate 31 returns to the lowered state.Operation for Attaching / Detaching Pad Holder to / from First Frame

[0099] When the separation pad 23 is worn, the user can remove the pad holder 40 holding the separation pad 23 from the first frame 90 and mount a new pad holder 40 to the first frame 90 as follows.

[0100] As shown in FIG. 6, the user raises the lock lever 29L to release the lock of the roller holder 28, and removes the roller holder 28, the feed roller 21, and the separation roller 22 from the second frame 29.

[0101] Because the separation roller 22 is separated from the separation pad 23, the pad holder 40 is biased by the first biasing force F1 of the torsion coil spring 25 of which the distal end 25A1 is in sliding contact with the first sliding contact sections 41, and swings from the first position shown in FIG. 5 to the holding position shown in FIG. 9.

[0102] The pad holder 40 is held at the holding position by being biased by the second biasing force F2 of the torsion coil spring 25 of which the distal end 25A1 is caught on the one ends 43A of the third sliding contact sections 43. The pad holder 40 is also held at the holding position by the hook 89F and the projecting section 48.

[0103] The user inserts fingers into an internal space of the opening 29H, pinches the swinging tip 40E side of the pad holder 40 with the finger, and pulls the pad holder 40 forward. Thus, the distal end 25A1 of the movable arm 25A of the torsion coil spring 25 moves from the one end 43A to the other ends 43B of the third sliding contact sections 43 and rides over the other ends 43B. The projecting section 48 that moves rearward also rides over the hook 89F.

[0104] As a result, the pad holder 40 is biased by the first biasing force F1 of the torsion coil spring 25 of which the distal end 25A1 is in sliding contact with the second sliding contact sections 42, and swings from the holding position shown in FIG. 9 to the second position shown in FIG. 10.

[0105] The user moves the pad holder 40 forward while pinching the swinging tip 40E side of the pad holder 40. Thus, as shown by a solid line in FIG. 2, the cutouts of the supported sections 49 of the pad holder 40 let the holder support shafts 94 pass therethrough. Thereafter, the user moves the pad holder 40 upward. As a result, the pad holder 40 is removed from the first frame 90.

[0106] The user pinches the swinging tip 40E side of a new pad holder 40, lowers the pad holder 40 to a state shown by a solid line in FIG. 2 via the internal space of the opening 29H, and then moves the pad holder 40 rearward. Thus, as shown by a two-dot chain line in FIG. 2, the cutouts of the supported sections 49 of the pad holder 40 let the holder support shafts 94 pass therethrough. As a result, the support walls 96 support the pad holder 40 so as to be swingable about the swing axis X40.

[0107] Then, the user pushes the swinging tip 40E side of the new pad holder 40 rearward. Thus, the distal end 25A1 of the movable arm 25A of the torsion coil spring 25 is brought into sliding contact with the second sliding contact sections 42, rides over the other ends 43B of the third sliding contact sections 43, and is caught on the one ends 43A of the third sliding contact sections 43. The projecting section 48 moving forward also rides over the hook 89F. In this state, the distal end 25A1 of the movable arm 25A is brought into sliding contact with the third sliding contact sections 43 from the second sliding contact sections 42, whereby the pad holder 40 is held at the holding position and the direction in which the movable arm 25A pushes the pad holder 40 changes. Therefore, it is easy for the user to know that the operation of pushing the swinging tip 40E side of the pad holder 40 rearward is completed at this point.

[0108] In a state where the user has released the pad holder 40, the pad holder 40 is biased by the second biasing force F2 of the torsion coil spring 25 of which the distal end 25A1 of the movable arm 25A is caught on the one ends 43A of the third sliding contact sections 43, and is held at the holding position. The pad holder 40 is also held at the holding position by the hook 89F and the projecting section 48.

[0109] Finally, as shown in FIG. 1, the user mounts the roller holder 28, the feed roller 21, and the separation roller 22 to the second frame 29, and, as shown in FIG. 3, lays down the lock lever 29L to lock the roller holder 28. As a result, the pad holder 40 is pushed by the separation roller 22 and swings to the first position, and replacement operation of the pad holder 40 and the separation pad 23 completes.Effects

[0110] In the image forming apparatus 1 of the embodiment, as shown in FIG. 6, with the separation roller 22 separated from the separation pad 23, that is, with the roller holder 28, the feed roller 21, and the separation roller 22 removed from the second frame 29, the pad holder 40 is biased by the torsion coil spring 25, swings from the first position shown in FIG. 5 to the holding position shown in FIG. 9, and is held at the holding position.

[0111] A user who performs replacement operation of the pad holder 40 swings the pad holder 40 from the holding position shown in FIG. 9 to the second position shown in FIG. 10. Thus, as shown in FIG. 11, the user can remove the pad holder 40 from the first frame 90.

[0112] Then, after attaching a new pad holder 40 to the first frame 90, the user swings the pad holder 40 from the second position shown in FIG. 10 to the holding position shown in FIG. 9. As a result, the pad holder 40 is biased by the second biasing force F2 of the torsion coil spring 25 of which the distal end 25A1 of the movable arm 25A is caught on the one ends 43A of the third sliding contact sections 43, and is held at the holding position.

[0113] Thus, with the image forming apparatus 1, it is possible to suppress the pad holder 40 held at the holding position from swinging to the second position and further swinging from the second position to a side opposite from the first position after the user releases the pad holder 40.

[0114] That is, the image forming apparatus 1 can suppress the pad holder 40 from swinging to the abnormal position shown by the two-dot chain line in FIGS. 5 and 10.

[0115] As a result, the pad holder 40 is less likely to take the abnormal posture in which the separation pad 23 faces downward, and when the separation roller 22 is mounted, the pad holder 40 swings from the holding position shown in FIG. 9 to the first position shown in FIG. 5.

[0116] Therefore, the image forming apparatus 1 of the embodiment can suppress the pad holder 40 from swinging, at the time of attachment of the pad holder 40, from the second position to the side opposite from the first position, and as a result can make it less likely that a failure occurs in which the separation roller 22 cannot convey the sheet SH.

[0117] In the image forming apparatus 1, as shown in FIG. 8, the pad holder 40 includes the first sliding contact sections 41, the second sliding contact sections 42, and the third sliding contact sections 43. As shown in FIG. 5, when the pad holder 40 swings between the first position and the holding position, the first sliding contact sections 41 slidably contacts the distal end 25A1 of the movable arm 25A of the torsion coil spring 25, thereby receiving from the torsion coil spring 25 the first biasing force F1 that swings the pad holder 40 toward the second position. As shown in FIG. 10, when the pad holder 40 swings between the holding position and the second position, the second sliding contact sections 42 slidably contacts the distal end 25A1 of the movable arm 25A of the torsion coil spring 25, thereby receiving the first biasing force F1 from the torsion coil spring 25. As shown in FIG. 9, when the pad holder 40 reaches the holding position from the first position or the second position, the third sliding contact sections 43 slidably contacts the distal end 25A1 of the movable arm 25A of the torsion coil spring 25 being caught on the third sliding contact sections 43, thereby receiving from the torsion coil spring 25 the second biasing force F2 that holds the pad holder 40 at the holding position. With this configuration, when the pad holder 40 swings between the first position and the second position, the direction of the biasing force from the torsion coil spring 25 acting on the pad holder 40 can be easily changed.

[0118] Further, in the image forming apparatus 1, as shown in FIG. 8, the pad holder 40 includes two ribs 47 on the side opposite from the opposing surface 40F. The first sliding contact sections 41, the second sliding contact sections 42, and the third sliding contact sections 43 are formed on each rib 47. With this configuration, the first sliding contact sections 41, the second sliding contact sections 42, and the third sliding contact sections 43 can be simplified.

[0119] In the image forming apparatus 1, as shown in FIG. 7, the torsion coil spring 25 includes the coil sections 25C, the engaging arms 25B engaging with the first frame 90, and the movable arm 25A whose distal end 25A1 contacts the pad holder 40. Such a torsion coil spring 25 can hold the pad holder 40 at the holding position with high reliability.

[0120] Further, in the image forming apparatus 1, as shown in FIGS. 5, 9, and 10, the coil center C1 is located downstream in the conveyance direction DT1 relative to the swing axis X40. When the pad holder 40 swings from the first position to the second position, the distal end 25A1 of the movable arm 25A moves upstream in the conveyance direction DT1 while in sliding contact with the pad holder 40. With this configuration, when the pad holder 40 swings between the first position and the second position, the direction of the biasing force of the torsion coil spring 25 acting on the pad holder 40 can be easily changed.

[0121] In the image forming apparatus 1, as shown in FIG. 9, the pad holder 40 includes the projecting section 48. The feed guide 89 includes the hook 89F that the projecting section 48 rides over when the pad holder 40 passes through the holding position. With the configuration in which a load acts on the pad holder 40 when the projecting section 48 rides over the hook 89F, the pad holder 40 can be held at the holding position with high reliability.

[0122] Further, in the image forming apparatus 1, as shown in FIG. 1, the image forming apparatus 1 includes the roller holder 28 that rotatably supports the separation roller 22, and the second frame 29 that detachably supports the roller holder 28. With this configuration, as shown in FIG. 6, as the user removes the roller holder 28 from the second frame 29, the pad holder 40 is biased by the torsion coil spring 25 to swing from the first position, and is held at the holding position as shown in FIG. 9. As a result, the user can attach and detach the pad holder 40 to and from the first frame 90 via a space where the roller holder 28 is no longer present, that is, via the internal space of the opening 29H. Then, after making the new pad holder 40 held at the holding position by swinging the pad holder 40 from the second position, the user attaches the roller holder 28 to the second frame 29 as shown in FIG. 1. Thus, the pad holder 40 swings from the holding position to the first position.

[0123] In the image forming apparatus 1, the image forming apparatus 1 includes the feed roller 21. The roller holder 28 also rotatably supports the feed roller 21. With this configuration, the space where the roller holder 28 is no longer present, that is, the internal space of the opening 29H, becomes larger by an amount corresponding to the feed roller 21, and thus the user can easily attach and detach the pad holder 40 to and from the first frame 90 via that space.

[0124] While the disclosure has been described in conjunction with various example structures outlined above and illustrated in the figures, various alternatives, modifications, variations, improvements, and / or substantial equivalents, whether known or that may be presently unforeseen, may become apparent to those having at least ordinary skill in the art. Accordingly, the example embodiments of the disclosure, as set forth above, are intended to be illustrative of the disclosure, and not limiting the disclosure. Various changes may be made without departing from the spirit and scope of the disclosure. Therefore, the disclosure is intended to embrace all known or later developed alternatives, modifications, variations, improvements, and / or substantial equivalents. Some specific examples of potential alternatives, modifications, or variations in the described invention are provided below:

[0125] In the embodiment, the sheet separation device of the present disclosure is embodied as the image forming apparatus 1 having an image forming function. However, the present disclosure is not limited to this configuration. For example, the configuration of the present disclosure may be applied to an image reading apparatus having only an image reading function, or may be applied to a multifunction peripheral having an image forming function and an image reading function.

[0126] In the embodiment, the torsion coil spring 25 is used as a biasing member. However, the present disclosure is not limited to this configuration. For example, the biasing member may be a compression coil spring, a tension coil spring, or the like.

Examples

Embodiment Construction

[0020]Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0021]An image forming apparatus 1 according to an embodiment shown in FIG. 1 is an example of a specific aspect of the sheet separation device of the present disclosure. In FIG. 1, a front face 9S side of a housing 9 is defined as the front of the apparatus, and the upper surface side of the housing 9 is defined as the upper side of the apparatus. The width direction of the image forming apparatus 1 is a direction orthogonal to a front-rear direction and an up-down direction. When facing the front face 9S of an apparatus main body (housing) 9, the left side, that is, the near side in FIG. 1, is defined as one side in the width direction. The front-rear direction, the up-down direction, and the width direction shown in FIG. 2 and the subsequent figures are all labeled to correspond to FIG. 1.

[0022]As shown in FIG. 1, the image forming apparatus 1 includes the housin...

REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from Japanese Patent Application No. 2025-054168 filed on Mar. 27, 2025. The entire content of the priority application is incorporated herein by reference.BACKGROUND ART

[0002] The present disclosure relates to a sheet separation device.

[0003] There is known a sheet feeding mechanism as an example of a conventional sheet separation device. In this sheet feeding mechanism, a separation roller conveys a sheet in a conveyance direction. A separation pad faces the separation roller and separates sheets conveyed by the separation roller. A pad holder holds the separation pad. A torsion spring biases the pad holder toward the separation roller. A unit case swingably supports the pad holder.

[0004] The pad holder is swingable between a contact position at which the separation pad is pressed toward the separation roller, and an upright position at which the separation roller is separated from the separation pad and the pad holder stands so that a swinging tip of the pad holder is located upstream in the conveyance direction relative to the contact position. The torsion spring biases the pad holder to swing toward the upright position. The pad holder is detachable from the unit case when in the upright position.SUMMARY

[0005] However, in the conventional sheet feeding mechanism described above, the pad holder biased by the torsion spring may swing from the upright position to a side opposite from the contact position. In this case, the problem is that the pad holder may take an abnormal posture in which the separation pad faces downward, and if the separation roller is installed in this state, the separation roller cannot convey sheets.

[0006] At least one aspect of the present disclosure is advantageous to provide a sheet separation device capable of suppressing the pad holder from swinging to an unintended position at the time of attachment of the pad holder, thereby making it less likely that a failure occurs in which the separation roller cannot convey sheets.

[0007] According to an aspect of the present disclosure, there is provided a sheet separation device including a separation roller configured to convey a sheet in a conveyance direction, a separation pad facing the separation roller and configured to separate sheets conveyed by the separation roller, a pad holder configured to hold the separation pad, a biasing member configured to bias the pad holder toward the separation roller, and a first frame configured to support the pad holder so as to be swingable about a swing axis. The pad holder is swingable to a first position in which the separation pad is pressed toward the separation roller, a second position in which the separation roller is separated from the separation pad and a swinging tip of the pad holder stands so as to be located upstream in the conveyance direction relative to the first position, and a holding position between the first position and the second position. The pad holder is detachable from the first frame when in the second position. When the pad holder swings between the first position and the holding position and when the pad holder swings between the holding position and the second position, the biasing member biases the pad holder so as to swing toward the second position, and when the pad holder reaches the holding position from the first position or the second position, the biasing member biases the pad holder so as to hold the pad holder at the holding position.BRIEF DESCRIPTION OF DRAWINGS

[0008] FIG. 1 is a schematic partial cross-sectional view of an image forming apparatus according to an embodiment, mainly illustrating a state in which a support plate of a deployed feed tray is separated downward from a feed roller.

[0009] FIG. 2 is a schematic partial cross-sectional view similar to FIG. 1, mainly illustrating a state in which the support plate of the deployed feed tray is raised.

[0010] FIG. 3 is a perspective view illustrating a first frame, a second frame, a roller holder, elevating arms, and the like.

[0011] FIG. 4 is a perspective view illustrating the first frame, a feed guide, a separation pad, a pad holder, the elevating arms, and the like.

[0012] FIG. 5 is a partial cross-sectional view illustrating the first frame, the feed guide, the separation pad, the pad holder, a torsion coil spring, and the like, showing a state in which the pad holder is at a first position.

[0013] FIG. 6 is a partial perspective view illustrating a state in which the roller holder is removed from the second frame.

[0014] FIG. 7 is a partial perspective view illustrating a state in which the separation pad and the pad holder are removed from the first frame.

[0015] FIG. 8 is a perspective view of the pad holder.

[0016] FIG. 9 is a partial cross-sectional view similar to FIG. 5, showing a state in which the pad holder is at a holding position.

[0017] FIG. 10 is a partial cross-sectional view similar to FIG. 5, showing a state in which the pad holder is at a second position.

[0018] FIG. 11 is a partial cross-sectional view similar to FIG. 5, illustrating an operation for attaching and detaching the pad holder to and from the first frame.

[0019] FIG. 12 is a schematic diagram illustrating a state in which the pad holder that has reached the holding position receives a biasing force from the biasing member.DESCRIPTION

[0020] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0021] An image forming apparatus 1 according to an embodiment shown in FIG. 1 is an example of a specific aspect of the sheet separation device of the present disclosure. In FIG. 1, a front face 9S side of a housing 9 is defined as the front of the apparatus, and the upper surface side of the housing 9 is defined as the upper side of the apparatus. The width direction of the image forming apparatus 1 is a direction orthogonal to a front-rear direction and an up-down direction. When facing the front face 9S of an apparatus main body (housing) 9, the left side, that is, the near side in FIG. 1, is defined as one side in the width direction. The front-rear direction, the up-down direction, and the width direction shown in FIG. 2 and the subsequent figures are all labeled to correspond to FIG. 1.

[0022] As shown in FIG. 1, the image forming apparatus 1 includes the housing 9, a sheet feeding cassette 2C, an image forming engine 2, and a conveyor (not shown). The housing 9 is substantially box-shaped and has a discharge tray 9T on an upper surface thereof. The sheet feeding cassette 2C is located in a lower portion inside the housing 9 and stores a plurality of sheets in a stacked state.

[0023] The image forming engine 2 is located in an upper portion inside the housing 9. The image forming engine 2 forms an image on a sheet by a general image forming method such as an electrophotographic method, a thermal method, an inkjet method, or the like.

[0024] The conveyor (not shown) supplies sheets one by one from the sheet feeding cassette 2C to the image forming engine 2. The image forming engine 2 forms an image on the sheet. Then, the conveyor (not shown) conveys the sheet on which the image has been formed and discharges the sheet to the discharge tray 9T.Feed Tray

[0025] As shown in FIG. 1, the image forming apparatus 1 includes a feed tray 3. The feed tray 3 is a multipurpose tray for feeding a plurality of types of sheets SH having different sizes, thicknesses, and the like to the image forming engine 2.

[0026] The feed tray 3 is located on the front face 9S side of the housing 9 and is deployed to extend forward from the front face 9S. Although not shown, the feed tray 3 is stowed in the housing 9 by pivoting upward and rearward to stand upright so that the feed tray 3 is aligned with the front face 9S of the housing 9.

[0027] An upward-facing surface of the deployed feed tray 3 is a support surface 3A capable of supporting the sheets SH. A conveyance direction DT1 in which the sheets SH supported on the support surface 3A are conveyed toward the image forming engine 2 is a rearward direction along the front-rear direction and is a direction orthogonal to the width direction. The feed tray 3 includes a feed tray main body 30, a support plate 31, and a sub-tray 30E.

[0028] The feed tray main body 30 is supported by the housing 9 so as to be pivotable. In a state where the feed tray 3 is deployed, the feed tray main body 30 extends from the front face 9S so as to be inclined upward toward an upstream side in the conveyance direction DT1.

[0029] The support plate 31 is located on an upward-facing surface side of the feed tray main body 30. The support plate 31 is supported by the feed tray main body 30 so as to be pivotable about an axis X31. The axis X31 extends in the width direction at an upstream end side of the support plate 31 in the conveyance direction DT1. As shown in FIGS. 1 and 2, the support plate 31 moves up and down by operation of elevating arms 6L and 6R described later.

[0030] The sub-tray 30E is pulled out from the feed tray main body 30 and extends so as to be inclined upward toward the upstream side in the conveyance direction DT1.

[0031] The support surface 3A is formed by an upward-facing surface of the support plate 31, an upward-facing surface of the sub-tray 30E, and the upward-facing surface of the feed tray main body 30 between the support plate 31 and the sub-tray 30E. A downstream end 3D of the support surface 3A in the conveyance direction DT1 is a downstream end of the support plate 31 in the conveyance direction DT1.First Frame, Feed Guide, Second Frame, and Gear Frame

[0032] As shown in FIGS. 1 and 3, the image forming apparatus 1 includes a first frame 90, a feed guide 89, and a second frame 29, which are located forward of the image forming engine 2. In the present embodiment, the first frame 90, the feed guide 89, and the second frame 29 are each a resin molded product manufactured by, for example, injection molding of a thermoplastic resin. The feed guide 89 and the first frame 90 are located below the second frame 29.

[0033] As shown in FIG. 4, the first frame 90 and the feed guide 89 extend in the width direction. As shown in FIGS. 4 and 5, the feed guide 89 is assembled to the first frame 90 from above to cover an upper portion of the first frame 90 and also cover an upper side of a front portion of the first frame 90.

[0034] The feed guide 89 includes a restricting surface 89A and a feed surface 89B. The restricting surface 89A is a forward-facing surface extending in the width direction. The restricting surface 89A is inclined such that an upper end thereof is positioned rearward of a lower end thereof. The feed surface 89B is an upward-facing surface connected to the upper end of the restricting surface 89A. The feed surface 89B extends so as to be inclined upward toward the downstream side in the conveyance direction DT1.

[0035] As shown in FIG. 1, the restricting surface 89A faces the downstream end 3D of the support surface 3A from the downstream side in the conveyance direction DT1. With the support plate 31 lowered, the restricting surface 89A abuts against and stops a downstream end in the conveyance direction DT1 of the sheet SH supported on the support surface 3A.

[0036] As shown in FIG. 4, the first frame 90 includes coupling sections 99L and 99R on upper end sides of portions located outside in the width direction relative to the feed surface 89B of the feed guide 89.

[0037] As shown in FIG. 3, the second frame 29 also extends in the width direction. One end of the second frame 29 in the width direction is coupled to the coupling section 99L, and the other end of the second frame 29 in the width direction is coupled to the coupling section 99R.

[0038] As shown in FIGS. 3 and 4, the image forming apparatus 1 includes a gear frame 80. In the present embodiment, similarly to the first frame 90 and the like, the gear frame 80 is a resin molded product manufactured by, for example, injection molding of a thermoplastic resin. The gear frame 80 is coupled to one end section 90L of the first frame 90 that is located on one side in the width direction.

[0039] The gear frame 80 is coupled to a side frame (not shown) located on one side surface side of the housing 9 in the width direction. The other end section 90R of the first frame 90 located on the other side in the width direction is coupled to another side frame (not shown) located on the other side surface side of the housing 9 in the width direction. The first frame 90 and the gear frame 80 constitute a reinforcing frame that extends like a beam in the width direction and is supported at both ends, thereby forming a part of an internal frame of the housing 9.Elevating Arms

[0040] The image forming apparatus 1 includes elevating arms 6L and 6R, and a driving force transmission mechanism (not shown) that transmits driving force to the elevating arms 6L and 6R.

[0041] The first frame 90 swingably supports the elevating arm 6L on the one end section 90L side, and swingably supports the elevating arm 6R on the other end section 90R side. The elevating arms 6L and 6R move distal ends thereof up and down by swinging.

[0042] The driving force transmission mechanism (not shown) includes a transmission gear group composed of a plurality of gears supported by the gear frame 80, an electromagnetic clutch, a transmission shaft supported by the first frame 90, a transmission gear, and the like.

[0043] Although not shown, the elevating arms 6L and 6R are in contact from below with pressed portions formed on a downstream end side of the support plate 31 in the conveyance direction DT1. The elevating arms 6L and 6R move the support plate 31 up and down when driving force is transmitted by the driving force transmission mechanism (not shown).Roller Holder, Feed Roller, and Separation Roller

[0044] As shown in FIG. 1, the image forming apparatus 1 includes a roller holder 28, a feed roller 21, and a separation roller 22.

[0045] As shown in FIGS. 3 and 6, the second frame 29 includes an opening 29H and a lock lever 29L.

[0046] The opening 29H is located at a center of the second frame 29 in the width direction. The opening 29H has a substantially rectangular shape in a top view and penetrates the second frame 29 in the up-down direction. The lock lever 29L is located on the other side in the width direction with respect to the opening 29H, and is swingably supported by the second frame 29.

[0047] The second frame 29 detachably supports the roller holder 28. The roller holder 28 is mounted to the second frame 29 by being fitted into the opening 29H and being locked by the lock lever 29L laid down.

[0048] When the user raises the lock lever 29L as indicated by an arrow Y1, the lock lever 29L releases the lock of the roller holder 28. Thus, the user can remove the roller holder 28 from the second frame 29. Also, the user can mount the roller holder 28 to the second frame 29 by performing a reverse operation.

[0049] As shown in FIG. 1, the roller holder 28 rotatably supports the feed roller 21 and the separation roller 22. That is, the feed roller 21 and the separation roller 22 can be attached to and detached from the second frame 29 together with the roller holder 28.

[0050] Lower portions of the feed roller 21 and the separation roller 22 are exposed below the second frame 29. The feed roller 21 is located above the support surface 3A and upstream in the conveyance direction DT1 relative to the downstream end 3D of the support surface 3A. The separation roller 22 is located above the feed surface 89B and downstream in the conveyance direction DT1 relative to the downstream end 3D of the support surface 3A. That is, the feed roller 21 is located upstream in the conveyance direction DT1 relative to the separation roller 22.Pad Holder, Separation Pad, and Torsion Coil Spring

[0051] The image forming apparatus 1 includes a pad holder 40, a separation pad 23, and a torsion coil spring 25.

[0052] As shown in FIGS. 4, 5, and 7, a rectangular hole 89H for exposing the pad holder 40 and the separation pad 23 is formed in a center of the feed surface 89B of the feed guide 89 in the width direction.

[0053] As shown in FIG. 7, the first frame 90 includes a pair of support walls 96. The support walls 96 are spaced apart from each other in the width direction. An upper edge of the support wall 96 located on one side in the width direction is adjacent to an inner peripheral edge of the rectangular hole 89H located on one side in the width direction. An upper edge of the support wall 96 located on the other side in the width direction is adjacent to an inner peripheral edge of the rectangular hole 89H located on the other side in the width direction.

[0054] Each support wall 96 includes a holder support shaft 94. Each holder support shaft 94 projects inward in the width direction from a portion located forward and upward on each support wall 96. Each holder support shaft 94 is a shaft having a substantially oblong cross-sectional shape about a swing axis X40 extending in the width direction.

[0055] As shown in FIG. 8, the pad holder 40 has a substantially rectangular flat-plate shape having a pair of long sides extending parallel to the swing axis X40 and a pair of short sides extending in a direction orthogonal to the swing axis X40. In the present embodiment, the pad holder 40 is a resin molded product manufactured by, for example, injection molding of a thermoplastic resin.

[0056] The pad holder 40 includes a pair of supported sections 49. Each supported section 49 is formed at each end side of the long side of the pad holder 40 located on the swing axis X40 side. Each supported section 49 is formed by cutting away a portion of a circular hole centered on the swing axis X40.

[0057] When the holder support shafts 94 are inserted into the respective supported sections 49, the support walls 96 of the first frame 90 swingably support the pad holder 40 about the swing axis X40 as shown in FIGS. 5 and 9 to 11.

[0058] In FIG. 11, a cross section of a portion of the pad holder 40 located below an imaginary line K1 is a cross section including the supported section 49 located on the other side in the width direction, and differs from the cross section of the pad holder 40 shown in FIGS. 5, 9, and 10. A minimum width of each holder support shaft 94 is a width of each holder support shaft 94 in the up-down direction. An inner width of the cutout of each supported section 49 is set slightly larger than the minimum width of each holder support shaft 94.

[0059] As shown in FIGS. 4 and 5, the pad holder 40 includes an opposing surface 40F. The separation pad 23 is a plate-like member. The separation pad 23 is held by the pad holder 40 by being attached to the opposing surface 40F with, for example, double-sided tape.

[0060] The separation pad 23 is made of a material having a friction coefficient smaller than a friction coefficient of a material forming a surface of the separation roller 22, such as natural rubber, synthetic rubber, cork, urethane, or the like.

[0061] As shown in FIGS. 5 and 8, the pad holder 40 includes a rear surface 40B. The rear surface 40B is a surface facing a side opposite from the opposing surface 40F.

[0062] As shown in FIG. 8, the pad holder 40 includes two ribs 47. Each rib 47 projects from the rear surface 40B, on a side opposite from the opposing surface 40F, in a circumferential direction of the swing axis X40, and extends in a radial direction of the swing axis X40. Also, as shown in FIG. 5, when the pad holder 40 is supported by the first frame 90, the pad holder 40 has the separation pad 23 on an upward-facing surface thereof, and the rear surface 40B on a downward-facing surface thereof has the two ribs 47. Each rib 47 projects downward from the rear surface 40B and extends in the front-rear direction along the rear surface 40B. As shown in FIG. 8, the ribs 47 are located at approximately a center of the rear surface 40B in the width direction and are spaced apart from each other in the width direction.

[0063] A swinging tip 40E of the pad holder 40 is a long side of the pad holder 40 that is far from the swing axis X40. Each rib 47 extends in the radial direction of the swing axis X40 from a position intersecting the swing axis X40 to the swinging tip 40E of the pad holder 40.

[0064] The ribs 47 reinforce the pad holder 40. A rib 47C located between the ribs 47 also reinforces the pad holder 40 together with the ribs 47.

[0065] The pad holder 40 includes first sliding contact sections 41, second sliding contact sections 42, and third sliding contact sections 43. The first sliding contact sections 41, the second sliding contact sections 42, and the third sliding contact sections 43 are formed on distal edges of the ribs 47 that are spaced from the rear surface 40B in the circumferential direction of the swing axis X40. That is, the first sliding contact sections 41, the second sliding contact sections 42, and the third sliding contact sections 43 are located on a side opposite from the opposing surface 40F.

[0066] As shown in FIGS. 8 and 12, with the first frame 90 supporting the pad holder 40, the first sliding contact sections 41 extend linearly forward from a vicinity of the swinging tip 40E of the pad holder 40. Each first sliding contact section 41 extends to a middle portion of each rib 47 in the front-rear direction. Note that, as shown in FIG. 5, in a state where the pad holder 40 is supported by the first frame 90 and the separation roller 22 and the separation pad 23 are in contact with each other, the first sliding contact section 41 of each rib 47 has a shape inclined such that a front end thereof is located lower than a rear end thereof.

[0067] As shown in FIG. 8, each second sliding contact section 42 is located closer to the swing axis X40 than the first sliding contact section 41 and extends substantially linearly forward. Each second sliding contact section 42 extends from a middle portion of each rib 47 in the front-rear direction to a vicinity of the swing axis X40. Note that, as shown in FIG. 5, in a state where the pad holder 40 is supported by the first frame 90 and the separation roller 22 and the separation pad 23 are in contact with each other, the second sliding contact section 42 of each rib 47 has a shape inclined such that a front end thereof is located lower than a rear end thereof.

[0068] As shown in FIG. 12, a distance between the first sliding contact section 41 and the rear surface 40B is defined as distance L1. A distance between the second sliding contact section 42 and the rear surface 40B is defined as distance L2. The distance L2 is greater than the distance L1. That is, a projecting length of a portion of each rib 47 on which the first sliding contact section 41 is formed is smaller than a projecting length of a portion of each rib 47 on which the second sliding contact section 42 is formed.

[0069] As shown in FIGS. 8 and 12, each third sliding contact section 43 is located between the first sliding contact section 41 and the second sliding contact section 42 and extends substantially linearly along the circumferential direction of the swing axis X40. One end 43A of the third sliding contact section 43 that is close to the rear surface 40B is connected to the first sliding contact section 41. The other end 43B of the third sliding contact section 43 that is far from the rear surface 40B is curved in a substantially “quarter arc” shape and connected to the second sliding contact section 42. Accordingly, each rib 47 has a stepped shape having the third sliding contact section 43 at an intermediate position in the front-rear direction. As shown in FIG. 5, in a state where the pad holder 40 is supported by the first frame 90 and the separation roller 22 and the separation pad 23 are in contact with each other, each rib 47 is inclined such that one end 43A of the third sliding contact section 43 is positioned above and forward of the other end 43B, and the inclination direction of the third sliding contact section 43 differs from the inclination direction of the first sliding contact section 41 and the second sliding contact section 42.

[0070] As shown in FIG. 12, a distance from the swing axis X40 to one end 43A of the third sliding contact section 43 is defined as distance L3A. A distance from the swing axis X40 to the other end 43B of the third sliding contact section 43 is defined as distance L3B. The distance L3B is slightly greater than the distance L3A.

[0071] As shown in FIGS. 5 and 8, the pad holder 40 includes a projecting section 48. The projecting section 48 projects from a center of the long side of the pad holder 40 located on the swing axis X40 side toward a side opposite from the opposing surface 40F. The projecting section 48 is a plate-like piece having a tapered shape in a side view.

[0072] As shown in FIGS. 5 and 7, the feed guide 89 includes a hook 89F. The hook 89F is located at a position slightly spaced downward from a center in the width direction of an inner peripheral edge, on a front side of the rectangular hole 89H, and projects rearward in a cantilever-beam shape. A rear end portion of the hook 89F has a hook-claw shape with a claw facing upward.

[0073] As shown in FIGS. 9 and 10, the hook 89F is positioned to interfere with the projecting section 48 when the pad holder 40 swings. The projecting section 48 rides over the hook 89F by bending the hook 89F downward.

[0074] As shown in FIG. 7, the first frame 90 includes, between the support walls 96, a pair of spring support shafts 95C and a pair of spring engagement recesses 95B.

[0075] The spring support shafts 95C are located rearward of the holder support shafts 94 and inward of the holder support shafts 94 in the width direction. Each spring support shaft 95C is a cylindrical projection projecting outward in the width direction. Each spring engagement recess 95B is located rearward of the spring support shaft 95C and is recessed downward.

[0076] The torsion coil spring 25 includes a pair of coil sections 25C, a pair of engaging arms 25B, and a movable arm 25A.

[0077] The coil sections 25C are spaced apart from each other in the width direction. Each coil section 25C is wound around a coil center C1 that is parallel to the swing axis X40. The engaging arms 25B extend rearward from respective coil sections 25C.

[0078] The movable arm 25A is bent into a substantially “U” shape, and a bottom portion of the “U” is a distal end 25A1. The movable arm 25A extends from the coil sections 25C to the distal end 25A1. The distal end 25A1 of the movable arm 25A extends substantially linearly in the width direction.

[0079] Each coil section 25C is fitted onto the spring support shaft 95C, and the engaging arms 25B engage with respective spring engagement recesses 95B. Thus, the torsion coil spring 25 is held by the first frame 90. As shown in FIG. 11, the coil center C1 is located downstream in the conveyance direction DT1 relative to the swing axis X40 and below the swing axis X40.

[0080] FIGS. 7 and 11 illustrate a natural length state in which the torsion coil spring 25 is not loaded. In this state, the movable arm 25A extends upward and slightly forward, and the distal end 25A1 is located upstream in the conveyance direction DT1 relative to the coil center C1.

[0081] The pad holder 40 is swingable to a first position shown in FIGS. 1, 2, and 4 to 6, a second position shown in FIG. 10, and a holding position shown in FIGS. 9 and 12. A position of the pad holder 40 shown by a two-dot chain line in FIG. 11 is also the second position. As shown in FIG. 9, the holding position is located between the first position and the second position.

[0082] As shown in FIG. 5, when the pad holder 40 swings to the first position, the pad holder 40 tilts such that the swinging tip 40E is located downstream in the conveyance direction DT1 relative to the swing axis X40.

[0083] As shown in FIG. 10, when the pad holder 40 swings to the second position, the pad holder 40 stands such that the separation roller 22 is separated from the separation pad 23 and the swinging tip 40E is located upstream in the conveyance direction DT1 relative to the first position. In this state, the swinging tip 40E is located substantially directly above the swing axis X40.

[0084] As shown in FIG. 11, when the pad holder 40 is at the second position, the cutouts of the supported sections 49 of the pad holder 40 are open rearward, thereby making it possible to make the holder support shaft 94 pass therethrough. That is, the pad holder 40 is attachable to and detachable from the first frame 90 when in the second position.

[0085] As shown in FIG. 5, when the pad holder 40 swings between the first position and the holding position, the first sliding contact sections 41 slidably contact the distal end 25A1 of the movable arm 25A of the torsion coil spring 25, thereby receiving from the torsion coil spring 25 a first biasing force F1 that makes the pad holder 40 swing toward the second position.

[0086] As shown in FIG. 10, when the pad holder 40 swings between the holding position and the second position, the second sliding contact sections 42 slidably contact the distal end 25A1 of the movable arm 25A of the torsion coil spring 25, thereby receiving the first biasing force F1 from the torsion coil spring 25. When the pad holder 40 swings to the second position, the torsion coil spring 25 returns to the natural length state, and the first biasing force F1 becomes zero.

[0087] That is, when the pad holder 40 swings between the first position and the holding position and when the pad holder 40 swings between the holding position and the second position, the torsion coil spring 25 biases the pad holder 40 so as to swing toward the second position.

[0088] As shown in FIG. 9, when the pad holder 40 reaches the holding position from the first position or the second position, the third sliding contact sections 43 slidably contact the distal end 25A1 of the movable arm 25A of the torsion coil spring 25 which is caught on the third sliding contact sections 43, thereby receiving from the torsion coil spring 25 a second biasing force F2 that holds the pad holder 40 at the holding position. At this time, as shown in FIG. 12, because the distance L3B is slightly greater than the distance L3A, the distal end 25A1 of the movable arm 25A caught on the third sliding contact sections 43 tends to move from the other ends 43B toward the one ends 43A of the third sliding contact sections 43. The second biasing force F2 is a force component, among force FF2 acting on the pad holder 40 from the distal end 25A1 caught on the third sliding contact sections 43, that acts toward the swing axis X40.

[0089] That is, when the pad holder 40 reaches the holding position from the first position or the second position, the torsion coil spring 25 biases the pad holder 40 so as to hold the pad holder 40 at the holding position.

[0090] When the pad holder 40 swings from the first position to the second position, the distal end 25A1 of the movable arm 25A moves upstream in the conveyance direction DT1 while sliding in contact with the first sliding contact sections 41, the third sliding contact sections 43, and the second sliding contact sections 42 of the pad holder 40.

[0091] When the pad holder 40 swings from the second position to the first position, the distal end 25A1 of the movable arm 25A moves downstream in the conveyance direction DT1 while sliding in contact with the second sliding contact sections 42, the third sliding contact sections 43, and the first sliding contact sections 41 of the pad holder 40.

[0092] As shown in FIG. 9, in a state where the torsion coil spring 25 biases the pad holder 40 so as to hold the pad holder 40 at the holding position, the hook 89F stops the projecting section 48 from the rear. That is, the hook 89F and the projecting section 48 also act to hold the pad holder 40 at the holding position. When the pad holder 40 passes through the holding position, the projecting section 48 rides over the hook 89F by bending the hook 89F downward.

[0093] A position of the pad holder 40 shown by a two-dot chain line in FIGS. 5 and 10 is an abnormal position that the pad holder reaches as the pad holder 40 swings from the second position to a side opposite from the first position.State Where Pad Holder Is at First Position

[0094] As shown in FIG. 5, when the feed roller 21 and the separation roller 22 are mounted to the second frame 29 together with the roller holder 28, the pad holder 40 is pushed by the separation roller 22 and swings to the first position.

[0095] In the state where the pad holder 40 is at the first position, the separation pad 23 and the opposing surface 40F face the separation roller 22 from below. In this state, the torsion coil spring 25 biases the pad holder 40 toward the separation roller 22 by bringing the distal end 25A1 of the movable arm 25A, which has moved downstream in the conveyance direction DT1 relative to the coil center C1, into contact with the first sliding contact sections 41.

[0096] That is, by swinging to the first position, the pad holder 40 brings the separation pad 23 into a state pressed toward the separation roller 22.Image Forming Operation on Sheet Supported on Feed Tray

[0097] When forming an image on the sheet SH supported on the feed tray 3, the elevating arms 6L and 6R raise their distal ends. Thus, as shown in FIG. 3, the support plate 31 rises and the feed roller 21 contacts an uppermost sheet SH supported on the support surface 3A. In this state, the feed roller 21 rotates to feed the uppermost sheet SH toward the separation roller 22 in the conveyance direction DT1. The feed surface 89B guides the sheet SH fed by the feed roller 21.

[0098] The separation roller 22 conveys the sheet SH fed by the feed roller 21 in the conveyance direction DT1. At this time, the separation roller 22 and the separation pad 23 separate the fed sheets SH one by one if a plurality of sheets SH are fed. The image forming engine 2 forms an image on the sheet SH conveyed by the separation roller 22. Thereafter, a conveyor (not shown) conveys the sheet SH on which the image has been formed and discharges the sheet SH to the discharge tray 9T. When the image forming operation ends, the elevating arms 6L and 6R lower their distal ends. Thus, as shown in FIG. 1, the support plate 31 returns to the lowered state.Operation for Attaching / Detaching Pad Holder to / from First Frame

[0099] When the separation pad 23 is worn, the user can remove the pad holder 40 holding the separation pad 23 from the first frame 90 and mount a new pad holder 40 to the first frame 90 as follows.

[0100] As shown in FIG. 6, the user raises the lock lever 29L to release the lock of the roller holder 28, and removes the roller holder 28, the feed roller 21, and the separation roller 22 from the second frame 29.

[0101] Because the separation roller 22 is separated from the separation pad 23, the pad holder 40 is biased by the first biasing force F1 of the torsion coil spring 25 of which the distal end 25A1 is in sliding contact with the first sliding contact sections 41, and swings from the first position shown in FIG. 5 to the holding position shown in FIG. 9.

[0102] The pad holder 40 is held at the holding position by being biased by the second biasing force F2 of the torsion coil spring 25 of which the distal end 25A1 is caught on the one ends 43A of the third sliding contact sections 43. The pad holder 40 is also held at the holding position by the hook 89F and the projecting section 48.

[0103] The user inserts fingers into an internal space of the opening 29H, pinches the swinging tip 40E side of the pad holder 40 with the finger, and pulls the pad holder 40 forward. Thus, the distal end 25A1 of the movable arm 25A of the torsion coil spring 25 moves from the one end 43A to the other ends 43B of the third sliding contact sections 43 and rides over the other ends 43B. The projecting section 48 that moves rearward also rides over the hook 89F.

[0104] As a result, the pad holder 40 is biased by the first biasing force F1 of the torsion coil spring 25 of which the distal end 25A1 is in sliding contact with the second sliding contact sections 42, and swings from the holding position shown in FIG. 9 to the second position shown in FIG. 10.

[0105] The user moves the pad holder 40 forward while pinching the swinging tip 40E side of the pad holder 40. Thus, as shown by a solid line in FIG. 2, the cutouts of the supported sections 49 of the pad holder 40 let the holder support shafts 94 pass therethrough. Thereafter, the user moves the pad holder 40 upward. As a result, the pad holder 40 is removed from the first frame 90.

[0106] The user pinches the swinging tip 40E side of a new pad holder 40, lowers the pad holder 40 to a state shown by a solid line in FIG. 2 via the internal space of the opening 29H, and then moves the pad holder 40 rearward. Thus, as shown by a two-dot chain line in FIG. 2, the cutouts of the supported sections 49 of the pad holder 40 let the holder support shafts 94 pass therethrough. As a result, the support walls 96 support the pad holder 40 so as to be swingable about the swing axis X40.

[0107] Then, the user pushes the swinging tip 40E side of the new pad holder 40 rearward. Thus, the distal end 25A1 of the movable arm 25A of the torsion coil spring 25 is brought into sliding contact with the second sliding contact sections 42, rides over the other ends 43B of the third sliding contact sections 43, and is caught on the one ends 43A of the third sliding contact sections 43. The projecting section 48 moving forward also rides over the hook 89F. In this state, the distal end 25A1 of the movable arm 25A is brought into sliding contact with the third sliding contact sections 43 from the second sliding contact sections 42, whereby the pad holder 40 is held at the holding position and the direction in which the movable arm 25A pushes the pad holder 40 changes. Therefore, it is easy for the user to know that the operation of pushing the swinging tip 40E side of the pad holder 40 rearward is completed at this point.

[0108] In a state where the user has released the pad holder 40, the pad holder 40 is biased by the second biasing force F2 of the torsion coil spring 25 of which the distal end 25A1 of the movable arm 25A is caught on the one ends 43A of the third sliding contact sections 43, and is held at the holding position. The pad holder 40 is also held at the holding position by the hook 89F and the projecting section 48.

[0109] Finally, as shown in FIG. 1, the user mounts the roller holder 28, the feed roller 21, and the separation roller 22 to the second frame 29, and, as shown in FIG. 3, lays down the lock lever 29L to lock the roller holder 28. As a result, the pad holder 40 is pushed by the separation roller 22 and swings to the first position, and replacement operation of the pad holder 40 and the separation pad 23 completes.Effects

[0110] In the image forming apparatus 1 of the embodiment, as shown in FIG. 6, with the separation roller 22 separated from the separation pad 23, that is, with the roller holder 28, the feed roller 21, and the separation roller 22 removed from the second frame 29, the pad holder 40 is biased by the torsion coil spring 25, swings from the first position shown in FIG. 5 to the holding position shown in FIG. 9, and is held at the holding position.

[0111] A user who performs replacement operation of the pad holder 40 swings the pad holder 40 from the holding position shown in FIG. 9 to the second position shown in FIG. 10. Thus, as shown in FIG. 11, the user can remove the pad holder 40 from the first frame 90.

[0112] Then, after attaching a new pad holder 40 to the first frame 90, the user swings the pad holder 40 from the second position shown in FIG. 10 to the holding position shown in FIG. 9. As a result, the pad holder 40 is biased by the second biasing force F2 of the torsion coil spring 25 of which the distal end 25A1 of the movable arm 25A is caught on the one ends 43A of the third sliding contact sections 43, and is held at the holding position.

[0113] Thus, with the image forming apparatus 1, it is possible to suppress the pad holder 40 held at the holding position from swinging to the second position and further swinging from the second position to a side opposite from the first position after the user releases the pad holder 40.

[0114] That is, the image forming apparatus 1 can suppress the pad holder 40 from swinging to the abnormal position shown by the two-dot chain line in FIGS. 5 and 10.

[0115] As a result, the pad holder 40 is less likely to take the abnormal posture in which the separation pad 23 faces downward, and when the separation roller 22 is mounted, the pad holder 40 swings from the holding position shown in FIG. 9 to the first position shown in FIG. 5.

[0116] Therefore, the image forming apparatus 1 of the embodiment can suppress the pad holder 40 from swinging, at the time of attachment of the pad holder 40, from the second position to the side opposite from the first position, and as a result can make it less likely that a failure occurs in which the separation roller 22 cannot convey the sheet SH.

[0117] In the image forming apparatus 1, as shown in FIG. 8, the pad holder 40 includes the first sliding contact sections 41, the second sliding contact sections 42, and the third sliding contact sections 43. As shown in FIG. 5, when the pad holder 40 swings between the first position and the holding position, the first sliding contact sections 41 slidably contacts the distal end 25A1 of the movable arm 25A of the torsion coil spring 25, thereby receiving from the torsion coil spring 25 the first biasing force F1 that swings the pad holder 40 toward the second position. As shown in FIG. 10, when the pad holder 40 swings between the holding position and the second position, the second sliding contact sections 42 slidably contacts the distal end 25A1 of the movable arm 25A of the torsion coil spring 25, thereby receiving the first biasing force F1 from the torsion coil spring 25. As shown in FIG. 9, when the pad holder 40 reaches the holding position from the first position or the second position, the third sliding contact sections 43 slidably contacts the distal end 25A1 of the movable arm 25A of the torsion coil spring 25 being caught on the third sliding contact sections 43, thereby receiving from the torsion coil spring 25 the second biasing force F2 that holds the pad holder 40 at the holding position. With this configuration, when the pad holder 40 swings between the first position and the second position, the direction of the biasing force from the torsion coil spring 25 acting on the pad holder 40 can be easily changed.

[0118] Further, in the image forming apparatus 1, as shown in FIG. 8, the pad holder 40 includes two ribs 47 on the side opposite from the opposing surface 40F. The first sliding contact sections 41, the second sliding contact sections 42, and the third sliding contact sections 43 are formed on each rib 47. With this configuration, the first sliding contact sections 41, the second sliding contact sections 42, and the third sliding contact sections 43 can be simplified.

[0119] In the image forming apparatus 1, as shown in FIG. 7, the torsion coil spring 25 includes the coil sections 25C, the engaging arms 25B engaging with the first frame 90, and the movable arm 25A whose distal end 25A1 contacts the pad holder 40. Such a torsion coil spring 25 can hold the pad holder 40 at the holding position with high reliability.

[0120] Further, in the image forming apparatus 1, as shown in FIGS. 5, 9, and 10, the coil center C1 is located downstream in the conveyance direction DT1 relative to the swing axis X40. When the pad holder 40 swings from the first position to the second position, the distal end 25A1 of the movable arm 25A moves upstream in the conveyance direction DT1 while in sliding contact with the pad holder 40. With this configuration, when the pad holder 40 swings between the first position and the second position, the direction of the biasing force of the torsion coil spring 25 acting on the pad holder 40 can be easily changed.

[0121] In the image forming apparatus 1, as shown in FIG. 9, the pad holder 40 includes the projecting section 48. The feed guide 89 includes the hook 89F that the projecting section 48 rides over when the pad holder 40 passes through the holding position. With the configuration in which a load acts on the pad holder 40 when the projecting section 48 rides over the hook 89F, the pad holder 40 can be held at the holding position with high reliability.

[0122] Further, in the image forming apparatus 1, as shown in FIG. 1, the image forming apparatus 1 includes the roller holder 28 that rotatably supports the separation roller 22, and the second frame 29 that detachably supports the roller holder 28. With this configuration, as shown in FIG. 6, as the user removes the roller holder 28 from the second frame 29, the pad holder 40 is biased by the torsion coil spring 25 to swing from the first position, and is held at the holding position as shown in FIG. 9. As a result, the user can attach and detach the pad holder 40 to and from the first frame 90 via a space where the roller holder 28 is no longer present, that is, via the internal space of the opening 29H. Then, after making the new pad holder 40 held at the holding position by swinging the pad holder 40 from the second position, the user attaches the roller holder 28 to the second frame 29 as shown in FIG. 1. Thus, the pad holder 40 swings from the holding position to the first position.

[0123] In the image forming apparatus 1, the image forming apparatus 1 includes the feed roller 21. The roller holder 28 also rotatably supports the feed roller 21. With this configuration, the space where the roller holder 28 is no longer present, that is, the internal space of the opening 29H, becomes larger by an amount corresponding to the feed roller 21, and thus the user can easily attach and detach the pad holder 40 to and from the first frame 90 via that space.

[0124] While the disclosure has been described in conjunction with various example structures outlined above and illustrated in the figures, various alternatives, modifications, variations, improvements, and / or substantial equivalents, whether known or that may be presently unforeseen, may become apparent to those having at least ordinary skill in the art. Accordingly, the example embodiments of the disclosure, as set forth above, are intended to be illustrative of the disclosure, and not limiting the disclosure. Various changes may be made without departing from the spirit and scope of the disclosure. Therefore, the disclosure is intended to embrace all known or later developed alternatives, modifications, variations, improvements, and / or substantial equivalents. Some specific examples of potential alternatives, modifications, or variations in the described invention are provided below:

[0125] In the embodiment, the sheet separation device of the present disclosure is embodied as the image forming apparatus 1 having an image forming function. However, the present disclosure is not limited to this configuration. For example, the configuration of the present disclosure may be applied to an image reading apparatus having only an image reading function, or may be applied to a multifunction peripheral having an image forming function and an image reading function.

[0126] In the embodiment, the torsion coil spring 25 is used as a biasing member. However, the present disclosure is not limited to this configuration. For example, the biasing member may be a compression coil spring, a tension coil spring, or the like.

Examples

Embodiment Construction

[0020]Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0021]An image forming apparatus 1 according to an embodiment shown in FIG. 1 is an example of a specific aspect of the sheet separation device of the present disclosure. In FIG. 1, a front face 9S side of a housing 9 is defined as the front of the apparatus, and the upper surface side of the housing 9 is defined as the upper side of the apparatus. The width direction of the image forming apparatus 1 is a direction orthogonal to a front-rear direction and an up-down direction. When facing the front face 9S of an apparatus main body (housing) 9, the left side, that is, the near side in FIG. 1, is defined as one side in the width direction. The front-rear direction, the up-down direction, and the width direction shown in FIG. 2 and the subsequent figures are all labeled to correspond to FIG. 1.

[0022]As shown in FIG. 1, the image forming apparatus 1 includes the housin...

Claims

1. A sheet separation device comprising:a separation roller configured to convey a sheet in a conveyance direction;a separation pad facing the separation roller and configured to separate sheets conveyed by the separation roller;a pad holder configured to hold the separation pad;a biasing member configured to bias the pad holder toward the separation roller; anda first frame configured to support the pad holder so as to be swingable about a swing axis,wherein the pad holder is swingable to a first position in which the separation pad is pressed toward the separation roller, a second position in which the separation roller is separated from the separation pad and a swinging tip of the pad holder stands so as to be located upstream in the conveyance direction relative to the first position, and a holding position between the first position and the second position,wherein the pad holder is detachable from the first frame when in the second position,wherein, when the pad holder swings between the first position and the holding position and when the pad holder swings between the holding position and the second position, the biasing member biases the pad holder so as to swing toward the second position, andwherein, when the pad holder reaches the holding position from the first position or the second position, the biasing member biases the pad holder so as to hold the pad holder at the holding position.

2. The sheet separation device according to claim 1,wherein the pad holder includes an opposing surface that faces the separation roller, and a first sliding contact section, a second sliding contact section, and a third sliding contact section located on a side opposite from the opposing surface,wherein the first sliding contact section slidably contacts the biasing member when the pad holder swings between the first position and the holding position, thereby receiving from the biasing member a first biasing force that swings the pad holder toward the second position,wherein the second sliding contact section slidably contacts the biasing member when the pad holder swings between the holding position and the second position, thereby receiving from the biasing member the first biasing force, andwherein the third sliding contact section is located between the first sliding contact section and the second sliding contact section, and slidably contacts the biasing member that is caught on the third sliding contact section when the pad holder reaches the holding position from the first position or the second position, thereby receiving from the biasing member a second biasing force that holds the pad holder at the holding position.

3. The sheet separation device according to claim 2,wherein the pad holder includes a rib that projects, on the side opposite from the opposing surface, in a circumferential direction and extends in a radial direction, andwherein the first sliding contact section, the second sliding contact section, and the third sliding contact section are formed on the rib.

4. The sheet separation device according to any one of claims claim 1 to 3,wherein the biasing member is a torsion coil spring including:a coil section wound about a coil center parallel to the swing axis;an engaging arm that extends from the coil section and engages the first frame; anda movable arm that extends from the coil section and has a distal end that contacts the pad holder.

5. The sheet separation device according to claim 4,wherein the coil center is located downstream in the conveyance direction relative to the swing axis, andwherein, when the pad holder swings from the first position to the second position, the distal end of the movable arm moves upstream in the conveyance direction while sliding in contact with the pad holder.

6. The sheet separation device according to any one of claims claim 1 to 3,wherein the pad holder includes an opposing surface that faces the separation roller and a projecting section that projects from a side opposite from the opposing surface, andwherein the sheet separation device includes a hook that the projecting section rides over when the pad holder passes through the holding position.

7. The sheet separation device according to any one of claims claim 1 to 3, further comprising:a roller holder configured to rotatably support the separation roller; anda second frame configured to detachably support the roller holder.

8. The sheet separation device according to claim 7, further comprising a feed roller located upstream in the conveyance direction relative to the separation roller and configured to feed a sheet toward the separation roller,wherein the roller holder is configured to rotatably support the feed roller.

Images