Sheet transport device

Abstract

The present invention provides a sheet conveying device that can suppress the disengagement of the engaging portion from the engaged portion when an impact is applied to the first roller, thereby making it less likely for the transmission member to come off the rotating shaft. [Solution] The sheet conveying device 1 includes a first roller 41 having a rotating shaft 41S, bearings 61 and 62 supporting the rotating shaft 41S, a transmission member 70 that rotates integrally with the rotating shaft 41S, and restricting parts 91 and 92 that restrict the axial movement of the rotating shaft 41S directly or with the bearings 61 and 62 interposed. The rotating shaft 41S has an engaged portion 43. The transmission member 70 has an engaging portion 73 that engages with the engaged portion 43 and restricts the transmission member 70 from disengaging from the rotating shaft 41S in the axial direction. The axial second clearance CL2 of the engaging portion 73 with respect to the engaged portion 43 is greater than the axial first clearance CL1 of the rotating shaft 41S with respect to the restricting parts 91 and 92.

Description

Technical Field

[0001] The present invention relates to a sheet conveying device.

Background Art

[0002] Patent Document 1 discloses an example of a conventional sheet conveying device. As shown in FIG. 9 thereof, in this sheet conveying device, the first roller has a shaft extending in the axial direction and conveys a sheet. The bearing supports the shaft. The first gear rotates integrally with the shaft and transmits a driving force to the shaft.

[0003] The shaft has an engaged portion. The engaged portion is recessed from the outer peripheral surface of the shaft in the radially inner direction of the shaft. The first gear has an engaging portion. The engaging portion has an elastically deformable cantilever beam and a key claw formed at the tip thereof. The engaging portion engages with the engaged portion to restrict the first gear from coming off the shaft in the axial direction.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the above conventional sheet conveying device, when a user carries the sheet conveying device and accidentally drops it, an impact acts on the shaft of the first roller, and when the shaft moves, the engaging portion may come off the engaged portion. As a result, the problem that the first gear comes off the shaft easily occurs.

[0006] The present invention has been made in view of the above-mentioned conventional circumstances, and aims to provide a sheet conveying device that can suppress the disengagement of the engaging portion from the engaged portion when an impact is applied to the first roller, and as a result, can make it less likely for the transmission member to come off the rotating shaft. [Means for solving the problem]

[0007] The sheet conveying device of the present invention has a rotating shaft extending in the axial direction, and a first roller for conveying sheets, A bearing that supports the aforementioned rotating shaft, A transmission member that rotates integrally with the aforementioned rotating shaft and transmits driving force to the aforementioned rotating shaft, A restricting unit that restricts the axial movement of the rotating shaft directly or through the bearing, Equipped with, The rotating shaft has an engaged portion, The transmission member has an engaging portion that engages with the engaged portion and restricts the transmission member from disengaging from the rotation shaft in the axial direction. The axial clearance of the rotating shaft with respect to the restricting portion is defined as the first clearance. If the axial clearance of the engaging portion with respect to the engaged portion is defined as the second clearance, The second clearance is characterized by being larger than the first clearance.

[0008] When a user carries the sheet conveying device of the present invention, an impact may be applied to the rotating shaft of the first roller, such as by accidentally dropping it. In this case, when the rotating shaft moves, the restricting part restricts the axial movement of the rotating shaft either directly or through a bearing.

[0009] In this case, because the second clearance is larger than the first clearance, the sheet conveying device can suppress the engagement portion from colliding with the engaged portion in the axial direction.

[0010] Therefore, the sheet conveying device of the present invention can suppress the disengagement of the engaging portion from the engaged portion when an impact is applied to the first roller, and as a result, it is possible to make it less likely for the transmission member to come off the rotating shaft. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a schematic cross-sectional view of the image forming apparatus of Example 1. [Figure 2] Figure 2 is a partial perspective view showing the first roller, first bearing, second bearing, second coupling, joint shaft, drive gear, drawer, second roller, transmission gear, etc. [Figure 3] Figure 3 is a partial perspective view showing the first roller, first bearing, second bearing, joint shaft, first coupling, drive gear, second roller, transmission gear, etc. [Figure 4] Figure 4 is a partial perspective view showing the first roller, first bearing, second coupling, joint shaft, drive gear, etc. [Figure 5] Figure 5 is a partial cross-sectional view showing cross-section AA of Figure 1, and shows the first roller, first bearing, transmission member, joint shaft, first coupling, drive gear, drawer, second roller, transmission gear, compression coil spring, frame, etc. [Figure 6] Figure 6 is a partial cross-sectional view showing section AA of Figure 1, and shows the first roller, second bearing, compression coil spring, frame, etc. [Figure 7] Figures 7(a) and 7(b) are partial cross-sectional views showing the BB cross-section of Figures 5 and 6, illustrating the first clearance and the second clearance. [Figure 8] Figure 8 is an exploded perspective view showing the first roller, first bearing, transmission member, and joint shaft. [Figure 9] Figure 9 is an exploded perspective view showing the first roller, the first bearing, and the transmission member. [Figure 10] Figure 10 is an exploded perspective view showing the rotation axis and transmission member of the first roller. [Figure 11]FIG. 11 is an exploded perspective view showing the rotation axis of the first roller and the transmission member, and is a view showing a part in cross section. [Figure 12] FIG. 12 is a cross-sectional view of the transmission member. [Figure 13] FIG. 13 is a cross-sectional view showing the C-C cross section of FIG. 12. [Figure 14] FIGS. 14(a) and (b) relate to the image forming apparatus of Example 2, and are partial cross-sectional views similar to FIG. 7, and are views for explaining the first clearance and the second clearance.

DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, Example 1 and Example 2 embodying the present invention will be described with reference to the drawings.

[0013] (Example 1) As shown in FIG. 1, the image forming apparatus 1 of Example 1 is an example of a specific aspect of the sheet conveying apparatus of the present invention. The image forming apparatus 1 is a color printer that forms an image on a sheet by an electrophotographic method.

[0014] <Schematic Configuration of Image Forming Apparatus> The image forming apparatus 1 includes an apparatus main body 9 that is a substantially box-shaped body, an image forming unit 3, a sheet tray 9C, a feeding unit 20, and a discharge roller pair 29 housed in the apparatus main body 9.

[0015] The sheet tray 9C is located below the image forming unit 3. The sheet tray 9C stores the sheets SH before the image is formed in a stacked state. The sheet SH is paper, an OHP sheet, or the like.

[0016] A discharge tray 9T is formed on the upper surface of the apparatus main body 9. The discharge tray 9T supports the sheet SH after the image formation.

[0017] An opening 9H is formed in the upper part of the front of the main body 9 of the device. The main body 9 of the device has a front cover 9F. The front cover 9F opens the opening 9H by protruding forward approximately horizontally from the lower end of the opening 9H. Although not shown in the illustration, the front cover 9F closes the opening 9H by swinging in the counterclockwise direction of the paper in Figure 1 to an upright position.

[0018] The width direction of the image forming apparatus 1 is perpendicular to the front-to-back and up-to-down directions. When facing the opening 9H and front cover 9F of the apparatus body 9, the left side, i.e., the front side of the page in Figure 1, is considered one width direction, and the back side of the page in Figure 1 is considered the other width direction. The front-to-back, up-to-down, and width directions shown in Figures 2 and onward correspond to those in Figure 1.

[0019] The width direction of the image forming apparatus 1 is an example of the "axial direction" of the present invention. One of the width directions is an example of the "one of the axial directions" of the present invention. The other of the width directions is an example of the "other of the axial directions" of the present invention.

[0020] As shown in Figure 1, the feeding unit 20 is located in front of the image forming unit 3. The feeding unit 20 has a feeding roller 21, a separation roller 22, a separation pad 22A, a transport roller pair 23, and a resist roller pair 24 arranged along the feeding path P1.

[0021] The feeding path P1 is a path that starts from the front end of the sheet tray 9C, moves forward and upward, then makes a U-turn, moves backward almost horizontally, and passes through the image forming unit 3.

[0022] The feed roller 21 sends the sheets SH contained in the sheet tray 9C to the feed path P1. The separation roller 22 and separation pad 22A separate the sheets SH sent by the feed roller 21 into individual sheets if multiple sheets are stacked on top of each other.

[0023] The transport roller pair 23 nips the sheets SH, which have been separated one by one by the separation roller 22 and separation pad 22A, and transports them toward the resist roller pair 24.

[0024] The resist roller pair 24 is located at the top of the U-turn portion in the feed path P1. The resist roller pair 24 has a first roller 41 and a second roller 42. The first roller 41 faces the second roller 42 from below. The second roller 42 rotates with the sheet SH sandwiched between it and the first roller 41.

[0025] The first roller 41 faces the second roller 42 in the first direction DP1. The first direction DP1 is a direction perpendicular to the width direction, and is inclined such that it shifts forward as it moves upward in the vertical direction and shifts backward as it moves downward in the vertical direction.

[0026] The specific configurations of the first roller 41 and the second roller 42 will be described later, but the first roller 41 and the second roller 42, while stationary, contact the leading edge of the sheet SH being conveyed toward the first roller 41 and the second roller 42, and after a predetermined time has elapsed, they start rotating to convey the sheet SH toward the image forming unit 3. This suppresses the skewing of the sheet SH.

[0027] The control of the rotation start of the first roller 41 and the second roller 42 is performed based on the timing when a sheet sensor (not shown), located between the transport roller pair 23 and the resist roller pair 24 in the feed path P1, detects the leading edge of the sheet SH.

[0028] Thus, the sheet SH, which is fed towards the image forming unit 3 by the feeding unit 20, passes through the image forming unit 3 in the portion of the feeding path P1 that extends approximately horizontally.

[0029] The image forming unit 3 is a direct transfer type color electrophotographic system. The image forming unit 3 includes a drawer 80, a toner storage unit 3G, a developing roller 3E, a charger 3F, a transfer belt 6, a scanner unit 8, and a fuser unit 7.

[0030] The drawer 80 has a well-known configuration, so its illustration is simplified, but it is a frame-like body made up of a pair of side walls located on the front and back sides of the paper in Figure 1, extending in the front-to-back direction, and a plurality of connecting members that extend in the width direction and connect the two side walls.

[0031] The main body of the apparatus 9 houses the drawer 80 in the first position shown by the solid line in Figure 1. The first position of the drawer 80 is the position in which the image forming unit 3 performs the image forming operation.

[0032] The drawer 80 has four photosensitive drums 5 corresponding to four toner colors: black, yellow, magenta, and cyan. The drawer 80 supports each photosensitive drum 5 so that it can rotate around a pivot axis that extends in the width direction. Each photosensitive drum 5 is arranged in series in the front-to-back direction along a substantially horizontal portion of the feed path P1.

[0033] The drawer 80 detachably supports four toner storage units 3G. Each toner storage unit 3G corresponds one-to-one with each photosensitive drum 5 and is arranged in series in the front-to-back direction along the substantially horizontal portion of the feed path P1. Each toner storage unit 3G contains toner of the corresponding color.

[0034] Four developing rollers 3E are held one-to-one with each toner storage unit 3G and are positioned around each photosensitive drum 5. Four chargers 3F are supported in a drawer 80 so as to face each photosensitive drum 5 one-to-one. The toner storage units 3G, developing rollers 3E, and chargers 3F are for forming an image on the sheet SH, which is conveyed by the first roller 41 and the second roller 42.

[0035] The main body of the device 9 supports the drawer 80 so that it can move forward from a first position by guide rails (not shown).

[0036] With the front cover 9F opening the opening 9H, the drawer 80 is movable between a first position shown by a solid line in Figure 1 and a second position shown by a dashed line in Figure 1. The second position of the drawer 80 is a position in which at least a portion of it is located outside the main body 9 of the device, and the toner storage section 3G can be replaced.

[0037] A guide rail (not shown) supports the rear end of the drawer 80 in the second position to prevent the front end of the drawer 80 from sagging. In other words, the drawer 80 in the second position is not removed from the device body 9, but remains connected to the device body 9.

[0038] Although not shown in the diagram, the user can remove the drawer 80 from the main body 9 by moving the drawer 80 forward from the second position. With the drawer 80 removed from the main body 9, the user can perform maintenance tasks such as removing jammed sheets SH in the supply path P1 or replacing consumables different from those in each toner storage section 3G.

[0039] The transfer belt 6 is positioned below each photosensitive drum 5, straddling the portion of the feed path P1 that extends approximately horizontally. The transfer belt 6 circulates while gripping the conveyed sheets SH with each photosensitive drum 5.

[0040] The scanner unit 8 is located above each photosensitive drum 5 and each toner storage unit 3G. The scanner unit 8 includes a laser light source, a polygon mirror, an fθ lens, a reflector, etc. The scanner unit 8 irradiates each photosensitive drum 5 with a laser beam from above.

[0041] In the drawer 80, the surface of each photosensitive drum 5 is uniformly positively charged by the charger 3F as it rotates, and then exposed by high-speed scanning of a laser beam irradiated from the scanner unit 8. As a result, an electrostatic latent image corresponding to the image to be formed on the sheet SH is formed on the surface of each photosensitive drum 5.

[0042] Next, the developing roller 3E supplies toner stored in the toner storage unit 3G to the surface of each photosensitive drum 5 in accordance with the electrostatic latent image, forming a toner image. Then, the first roller 41 and the second roller 42 transport the sheet SH toward each photosensitive drum 5, and as the sheet SH passes between each photosensitive drum 5 and the transfer belt 6, the upward-facing side of the sheet SH faces each photosensitive drum 5. The toner image carried on the surface of each photosensitive drum 5 is transferred to the upward-facing side of the sheet SH.

[0043] The fuser unit 7 is located behind the drawer 80. The fuser unit 7 heats and pressurizes the sheet SH while it is being transported between the heating roller 7A and the pressure roller 7B, thereby heat-fixing the toner image onto the sheet SH.

[0044] The discharge roller pair 29 is positioned at the downstream end of the discharge path P2. The discharge path P2 is a path that guides the sheet SH that has passed through the fuser 7 upwards and then makes a U-turn so that the surface on which the image is formed faces downwards before discharging it to the discharge tray 9T. The discharge roller pair 29 nips the sheet SH as it is transported along the discharge path P2 and discharges it to the discharge tray 9T.

[0045] <Second roller bearing and second roller> The drawer 80 shown in Figure 2 is in the second position. The drawer 80 has second roller bearings 82L and 82R. The second roller bearing 82L is located at one corner in the width direction on the front and bottom of the drawer 80. The second roller bearing 82R is located at the other corner in the width direction on the front and bottom of the drawer 80.

[0046] Although the drawer 80 is not shown in Figure 3, the positions of the second roller bearings 82L and 82R shown in Figure 3 correspond to the drawer 80 in the first position.

[0047] As shown in Figures 2 and 3, the second roller 42 has a second roller rotation shaft 42S and a second roller body 42A.

[0048] The second roller rotation shaft 42S is a metal cylinder extending in the width direction. The second roller body 42A is a cylindrical body fixed to the second roller rotation shaft 42S with both ends in the width direction of the second roller rotation shaft 42S exposed.

[0049] The drawer 80 rotatably supports the second roller 42 by supporting both ends in the width direction of the second roller rotation shaft 42S with the second roller bearings 82L and 82R.

[0050] A transmission gear 56 is fixed to the portion of the second roller rotation shaft 42S that protrudes in one direction in the width direction from the second roller bearing 82L. The transmission gear 56 rotates together with the second roller 42.

[0051] The second roller bearings 82L and 82R have positioning grooves 88. The positioning grooves 88 are formed in the portion of the second roller bearings 82L and 82R that is located below and behind the second roller rotation axis 42S, and are recessed upward and forward to approach the second roller rotation axis 42S.

[0052] <Frame and side frames> The main body of the device 9 has multiple internal frames, such as the frames 90 shown in Figures 2 to 7, and the side frames 99 shown in Figures 5 and 7.

[0053] As shown in Figure 2, the frame 90 extends in the width direction and supports the separation roller 22 of the feeding unit 20, etc., at its lower portion.

[0054] As shown in Figures 5 and 7, the side frame 99 extends in the front-to-back and up-to-down directions along one side of the device body 9 in the width direction. Although not shown in the illustration, one end of the frame 90 in the width direction is connected to the side frame 99.

[0055] The drawer 80 shown in Figure 5 is in the first position. With the drawer 80 in the first position, the second roller bearing 82L faces the side frame 99 from the other side in the width direction.

[0056] <First Laura> As shown in Figures 7 to 9, the first roller 41 has a rotating shaft 41S and a roller body 41A. The rotating shaft 41S is a metal cylinder centered on an axis X1 that extends in the width direction (axial direction of the first roller 41). The roller body 41A is a cylindrical body fixed to the rotating shaft 41S.

[0057] The rotating shaft 41S has a first projection 41S1. The first projection 41S1 protrudes from the roller body 41A in one direction in the width direction. The first projection 41S1 has a C-type retaining ring 41C1, an engaged portion 43, a cylindrical shaft portion 44, and a fitting shaft portion 45.

[0058] The C-type retaining ring 41C1 is recessed in the radial direction toward the axis X1 from the outer circumferential surface of the first projection 41S1 near the roller body 41A, and is fitted into a groove of the rotating shaft 41S that makes one full turn in the circumferential direction of the axis X1.

[0059] The engaged portion 43 is a recess that is slightly separated from the C-type retaining ring 41C1 in one width direction, recessed in the radial direction toward the axis X1 from the outer circumferential surface of the first projection 41S1, and extends around the axis X1 in a full circle.

[0060] The cylindrical shaft portion 44 is a cylinder that connects to the engaged portion 43 from one side in the width direction. The cylindrical shaft portion 44 has a cylindrical outer surface and extends in one side in the width direction.

[0061] The fitting shaft portion 45 is connected to the cylindrical shaft portion 44 from one side in the width direction. The fitting shaft portion 45 has a flat surface shape, with a portion of its cylindrical outer surface extending in the width direction, and has a flat surface 45F. The outer surface of the fitting shaft portion 45 has the same diameter as the outer surface of the cylindrical shaft portion 44 and is continuous without any steps. The fitting shaft portion 45 protrudes from one side in the width direction.

[0062] As shown in Figure 8, abutment surface 44T is formed at the connection point between the cylindrical shaft portion 44 and the fitting shaft portion 45. The abutment surface 44T is a semicircular flat surface facing in one direction in the width direction.

[0063] As shown in Figure 7, the rotating shaft 41S has a second projection 41S2. The second projection 41S2 protrudes in the other direction in the width direction. The second projection 41S2 has a C-type retaining ring 41C2.

[0064] The C-type retaining ring 41C2 is recessed in the radial direction toward the axis X1 from the outer circumferential surface of the second projection 41S2 near the roller body 41A, and is fitted into a groove of the rotating shaft 41S that makes one full turn in the circumferential direction of the axis X1.

[0065] The support configuration for the first protrusion 41S1 and the second protrusion 41S2 of the rotating shaft 41S will be described later.

[0066] <Transmission Member> As shown in Figures 4, 5 and 7-13, the feeding unit 20 has a transmission member 70. The transmission member 70 is a resin molded product manufactured by injection molding of thermoplastic resin or the like.

[0067] Since the rotating shaft 41S and the transmission member 70 are rotatable around the axis X1, for the sake of clarity, the cross-sections of the rotating shaft 41S and the transmission member 70 in Figure 7 are shown as in Figure 5.

[0068] As shown in Figures 10 to 13, the transmission member 70 has a substantially cylindrical shape with a fitting hole portion 75. The fitting hole portion 75 has an inner circumferential surface 75C and an insertion opening 75E. The inner circumferential surface 75C is a cylindrical surface centered on the axis X1. The insertion opening 75E is an opening formed by the other edge in the width direction of the inner circumferential surface 75C.

[0069] As shown in Figures 9 to 12, the transmission member 70 has an engaging portion 73. The engaging portion 73 is formed between two grooves that extend in one direction in the width direction from the insertion opening 75E of the transmission member 70. The engaging portion 73 has a cantilever shape that protrudes in the other direction in the width direction, and at its tip located near the insertion opening 75E, it has a claw that protrudes in the radially inward direction of the axis X1.

[0070] As shown in Figures 10 to 13, the transmission member 70 has a contact portion 76. The contact portion 76 is a protrusion formed on the inner circumferential surface 75C of the fitting hole portion 75.

[0071] As shown in Figure 12, the contact portion 76 is located slightly offset to one side in the width direction from the center in the width direction on the inner circumferential surface 75C. The contact portion 76 is located on the opposite side of the engaging portion 73 with respect to the axis X1.

[0072] As shown in Figure 13, the contact portion 76 has a pair of first portions 76A and 76B and a second portion 76C.

[0073] The pair of first parts 76A and 76B are convex portions that are spaced apart from each other in the circumferential direction of the axis X1 and each extends in the width direction.

[0074] The second part 76C extends in the circumferential direction of the axis X1 and connects to the ends of the first parts 76A and 76B that are close to the insertion opening 75E, i.e., to the other ends in the width direction.

[0075] In other words, the contact portion 76 has a roughly "C"-shaped cutout. The contact surface 76F of the contact portion 76 is formed by the tip surfaces of both first portions 76A and 76B and the tip surface of the second portion 76C. The contact surface 76F is a flat surface that extends in the width direction.

[0076] As shown in Figures 8 and 11 to 13, the transmission member 70 has a second coupling 52. The second coupling 52 is an example of the "coupling" of the present invention. The second coupling 52 is connected to the fitting hole 75 from one side in the width direction.

[0077] As shown in Figure 11, the inner circumferential surface 75C extends to the second coupling 52. The second coupling 52 has a portion of the inner circumferential surface 75C from one end edge in the width direction to the vicinity of the contact portion 76, and a pair of grooves 52J1 that are recessed radially outward from that portion toward the axis X1. Both grooves 52J1 extend from one end edge in the width direction of the inner circumferential surface 75C toward the other end in the width direction, and stop at a position separated from the contact portion 76 in one direction in the width direction.

[0078] As shown in Figure 10, the portion of the second coupling 52 corresponding to both grooves 52J1 bulges outward in the radial direction of the axis X1 compared to the outer circumferential surface of the fitting hole 75. A butt surface 52T is formed at the connection portion of the second coupling 52 with the fitting hole 75. The butt surface 52T is a substantially annular flat surface facing the other side in the width direction.

[0079] <Assembly of the transmission member to the first projection of the rotating shaft> The procedure for assembling the transmission member 70 to the first projection 41S1 of the rotating shaft 41S will now be described. First, as shown in Figures 10 and 11, the transmission member 70 is positioned on one side in the width direction relative to the first projection 41S1, and the axis of the transmission member 70 is aligned with the axis X1.

[0080] Next, the engaging portion 73 is positioned on the opposite side of the flat surface 45F with respect to the axis X1. This makes it easy to align the phase of the flat surface 45F with the contact surface 76F of the contact portion 76, which is difficult to see with the naked eye.

[0081] Next, the fitting shaft portion 45 is inserted into the insertion opening 75E of the transmission member 70, and the fitting hole portion 75 is fitted onto the fitting shaft portion 45 and the cylindrical shaft portion 44, while the phase-aligned flat surface 45F and the contact surface 76F of the contact portion 76 are brought into contact. At this time, the tip of the engaging portion 73 initially rides up onto the cylindrical outer surface of the fitting shaft portion 45, so that the fitting hole portion 75 can then be smoothly fitted onto the fitting shaft portion 45 and the cylindrical shaft portion 44 without being hindered by the engaging portion 73.

[0082] As shown in Figures 7(a) and (b), the engaging portion 73 is positioned on the opposite side of the axis X1 from the flat surface 45F and the contact portion 76, with respect to the axis X1, with the fitting hole portion 75 fitted onto the fitting shaft portion 45 and the cylindrical shaft portion 44, and engages with the engaged portion 43 by inserting the claw at its tip into the engaged portion 43. In this way, the engaging portion 73 restricts the transmission member 70 from coming out of the first protrusion portion 41S1 in the width direction.

[0083] The transmission member 70, which is assembled to the first protrusion 41S1, rotates integrally with the rotating shaft 41S. The contact portion 76 restricts the rotation of the transmission member 70 relative to the rotating shaft 41S by having its contact surface 76F contact the flat surface 45F. The transmission member 70 transmits the driving force of the motor M1, which will be described later, to the rotating shaft 41S.

[0084] <Frame rails, spring bases, and guide protrusions> As shown in Figures 2 and 7, the frame 90 has a first restricting section 91 and a second restricting section 92. The first restricting section 91 and the second restricting section 92 are examples of the "restricting section" of the present invention.

[0085] As shown in Figure 7, the first restricting portion 91 and the second restricting portion 92 are located outside the roller body 41A of the first roller 41 in the width direction.

[0086] As shown in Figure 4, the first regulating section 91, located in one direction in the width direction, is a rail that extends upward and slightly forward along the first direction DP1 from a position below the first roller 41. The upper end of the first regulating section 91 is located in front of the first roller 41. As shown in Figure 7, the surface of the first regulating section 91 facing the other direction in the width direction is the first regulating surface 91K.

[0087] As shown in Figure 2, the second restricting section 92, located on the other side in the width direction, is a rail that extends upward and slightly forward along the first direction DP1 from a position below the first roller 41, similar to the first restricting section 91. The upper end of the second restricting section 92 is located in front of the first roller 41. As shown in Figure 7, the surface of the second restricting section 92 facing one side in the width direction is the second restricting surface 92K.

[0088] As shown in Figure 3, the frame 90 has spring bases 95L and 95R. The spring bases 95L and 95R are located outside the widthwise direction of the roller body 41A of the first roller 41.

[0089] As shown in Figures 3 and 5, the spring base 95L located on one side in the width direction is positioned behind and below the first roller 41. As shown in Figure 5, a guide projection 94L is formed on the side of the spring base 95L facing one side in the width direction, so as to protrude in that direction.

[0090] As shown in Figures 3 and 6, the spring base 95R located on the other side in the width direction is positioned behind and below the first roller 41. As shown in Figure 6, a guide projection 94R is formed on the side of the spring base 95R facing the other side in the width direction, so as to protrude in the other side in the width direction.

[0091] <Compression coil spring> As shown in Figure 3, the feeding unit 20 is equipped with compression coil springs 49L and 49R. The compression coil springs 49L and 49R are examples of the "biasing member" of the present invention.

[0092] As shown in Figures 3 and 5, the lower end of the compression coil spring 49L located on one side in the width direction is locked to the spring base 95L.

[0093] As shown in Figures 3 and 6, the lower end of the compression coil spring 49R located on the other side in the width direction is locked to the spring base 95R.

[0094] <First and second bearings> As shown in Figure 3, the feeding unit 20 is equipped with a first bearing 61 and a second bearing 62. The first bearing 61 and the second bearing 62 are examples of the "bearings" of the present invention. The first bearing 61 and the second bearing 62 are resin molded products manufactured by injection molding of thermoplastic resin or the like.

[0095] As shown in Figures 4 and 5, the first bearing 61 has a cylindrical upper portion and a flat plate lower portion. An elongated hole 61J extending in the first direction DP1 is formed in the lower portion of the first bearing 61. The guide projection 94L is inserted through the elongated hole 61J.

[0096] As shown in Figure 5, the upper end of the compression coil spring 49L is locked to the upper part of the first bearing 61. As shown in Figure 7, a shaft hole 61H is formed in the upper part of the first bearing 61, extending through in the width direction. The inner diameter of the shaft hole 61H is slightly larger than the outer diameter of the fitting shaft portion 45 and the cylindrical shaft portion 44.

[0097] The shaft hole 61H accommodates the cylindrical shaft portion 44 and the fitting shaft portion 45 of the first projection 41S1, and the fitting hole portion 75 of the transmission member 70. Thus, the first bearing 61 rotatably supports the first projection 41S1 of the rotating shaft 41S. The second coupling 52 is located on one side in the width direction relative to the upper portion of the first bearing 61.

[0098] The upper portion of the first bearing 61 has first restricted portions 61K1 and 61K2 formed thereon.

[0099] The first restricted portion 61K1 is formed at the other end in the width direction of the upper part of the first bearing 61 and protrudes forward. The first restricted portion 61K2 is formed at a portion of the upper part of the first bearing 61 separated from the first restricted portion 61K1 in one direction in the width direction, protrudes forward, and then bends to the other direction in the width direction.

[0100] The first restricted portions 61K1 and 61K2 surround the first restricting portion 91. As a result, the first restricting portion 91 supports the first bearing 61 so that it can move in the first direction DP1. The compression coil spring 49L biases the first bearing 61 so that the first roller 41 presses against the second roller 42 along the first direction DP1.

[0101] As shown in Figure 6, the second bearing 62 has a cylindrical upper portion and a flat lower portion. An elongated hole 62J extending in the first direction DP1 is formed in the lower portion of the second bearing 62. The guide projection 94R is inserted through the elongated hole 62J.

[0102] The upper end of the compression coil spring 49R is locked to the upper part of the second bearing 62. A shaft hole 62H is formed in the upper part of the second bearing 62, extending through in the width direction. The inner diameter of the shaft hole 62H is slightly larger than the outer diameter of the second projection 41S2.

[0103] The shaft hole 62H accommodates the second projection 41S1. As a result, the second bearing 62 rotatably supports the second projection 41S2 of the rotating shaft 41S.

[0104] As shown in Figure 7, the upper portion of the second bearing 62 has second restricted portions 62K1 and 62K2 formed thereon.

[0105] The second restricted portion 62K1 is formed at one end in the width direction of the upper part of the second bearing 62 and protrudes forward. The second restricted portion 62K2 is formed at a portion of the upper part of the second bearing 62 that is separated from the second restricted portion 62K1 in the other width direction, and after protruding forward, it bends to one side in the width direction.

[0106] The second restricted portions 62K1 and 62K2 surround the second restricted portion 92. As a result, the second restricted portion 92 supports the second bearing 62 so that it can move in the first direction DP1. The compression coil spring 49R biases the second bearing 62 so that the first roller 41 presses against the second roller 42 along the first direction DP1.

[0107] As shown in Figure 7, the portion of the upper part of the first bearing 61 located in one width direction relative to the first restricted portion 61K2 is a positioning projection 61P. The portion of the upper part of the second bearing 62 located in the other width direction relative to the second restricted portion 62K2 is a positioning projection 62P. Each of the positioning projections 61P and 61P has a cylindrical outer surface.

[0108] As shown in Figure 3, when the drawer 80 moves to the first position, the biasing force of the compression coil springs 49R and 49L causes the positioning projection 61P of the first bearing 61 to engage with the positioning groove 88 of the second roller bearing 82L, and the positioning projection 62P of the second bearing 62 to engage with the positioning groove 88 of the second roller bearing 82R. As a result, the first roller 41 is positioned relative to the second roller 42. At this time, the transmission gear 56 meshes with the drive gear 50.

[0109] <Motor, electromagnetic clutch, drive gear, and joint shaft> As shown in Figure 5, the image forming apparatus 1 is equipped with a motor M1 and an electromagnetic clutch C1.

[0110] Motor M1 generates driving force by being controlled and operated by a control unit (not shown). The driving force of motor M1 is transmitted to the feeding roller 21, the separating roller 22, the transport roller pair 23, the discharge roller pair 29, and the image forming unit 3 via a plurality of transmission mechanisms (not shown).

[0111] The electromagnetic clutch C1 is controlled and operated by a control unit (not shown) to switch between transmitting and disconnecting the driving force of the motor M1.

[0112] Furthermore, the driving force of the motor M1 is transmitted to the first roller 41 and the second roller 42 via the electromagnetic clutch C1, etc., as described below.

[0113] As shown in Figures 5 and 7, the image forming apparatus 1 is equipped with a drive gear 50 and a joint shaft 55.

[0114] Since the drive gear 50 and joint shaft 55 are rotatable around the axis X1, for the sake of clarity, the cross-sections of the drive gear 50 and joint shaft 55 in Figure 7 are shown as in Figure 5.

[0115] As shown in Figure 5, the drive gear 50 integrally comprises a supported portion 50A, a flange 51F, a clutch shaft 51S, and a first coupling 51. The drive gear 50, supported portion 50A, flange 51F, clutch shaft 51S, and first coupling 51 are a single resin molded product manufactured by injection molding of thermoplastic resin or the like.

[0116] The supported portion 50A is located on the other side in the width direction from the drive gear 50. The supported portion 50A is a cylinder with a smaller diameter than the drive gear 50.

[0117] The flange 51F is located on one side in the width direction relative to the drive gear 50. The flange 51F is a larger diameter disc than the drive gear 50.

[0118] The clutch shaft 51S is located on one side in the width direction relative to the flange 51F. The clutch shaft 51S is a cylinder with a smaller diameter than the supported portion 50A and extends in one direction in the width direction. The clutch shaft 51S is inserted into the electromagnetic clutch C1.

[0119] The first coupling 51 is formed such that a pair of grooves 51J1 extend in the width direction on the inner circumferential surface of a recess that is recessed in one direction in the width direction from the other end face in the width direction of the supported portion 50A.

[0120] As shown in Figures 5 and 7, the side frame 99 has a support portion 99A at a position separated from the second coupling 52 in one width direction. The support portion 99A has a cylindrical inner surface that is slightly larger than the outer surface of the supported portion 50A and has a portion of its upper part cut out.

[0121] The side frame 99 has a flange receiving portion 99F at a position separated from the support portion 99A in one direction in the width direction. The flange receiving portion 99F is an annular flat surface that is larger than the outer diameter of the drive gear 50 and smaller than the outer diameter of the flange 51F, and has a flat surface facing one direction in the width direction.

[0122] The side frame 99 rotatably supports the drive gear 50 and the first coupling 51 by having the support portion 99A rotatably support the supported portion 50A and the flange 51F abutting against the flange receiving portion 99F from one side in the width direction.

[0123] As shown in Figures 7 and 8, the joint shaft 55 extends in the width direction. The joint shaft 55 has spherical ends 55W1 and 55W2 in the width direction, and the two ends are connected by a multi-stage cylinder extending in the width direction. Each end 55W1 and 55W2 of the joint shaft 55 has a pair of cylindrical protrusions. The joint shaft 55 is a resin molded product manufactured by injection molding of thermoplastic resin or the like.

[0124] As shown in Figure 7, the joint shaft 55 is connected to the first coupling 51 by one end 55W1 in the width direction entering the first coupling 51 and a pair of cylindrical protrusions engaging with a pair of grooves 51J1.

[0125] Furthermore, the joint shaft 55 is connected to the second coupling 52 by the other end 55W2 in the width direction entering the second coupling 52 and a pair of cylindrical protrusions engaging with a pair of grooves 52J1.

[0126] In this way, the first coupling 51, the joint shaft 55, and the second coupling 52 constitute a universal joint. The joint shaft 55 transmits driving force from the first coupling 51 to the second coupling 52 even if the position of the axis X1 of the second coupling 52 is shifted relative to the rotation axis of the first coupling 51 due to the movement of the first bearing 61 and the second bearing 62.

[0127] <Transmission of motor driving force to the first and second rollers> When the control unit (not shown) is not energized to the electromagnetic clutch C1, the electromagnetic clutch C1 will interrupt the transmission of driving force to the drive gear 50 and the first coupling 51, even if the motor M1 is operating.

[0128] When the motor M1 is operating, and a control unit (not shown) starts energizing the electromagnetic clutch C1, the electromagnetic clutch C1 transmits driving force to the drive gear 50 and the first coupling 51. As a result, the drive gear 50, the first coupling 51, and the joint shaft 55 rotate in response to the driving force of the motor M1.

[0129] As a result, the second coupling 52 receives driving force from the drive gear 50 and the first coupling 51 via the joint shaft 55, and the transmission member 70 having the second coupling 52 transmits the driving force to the first roller 41. The transmission gear 56 that meshes with the drive gear 50 transmits driving force to the second roller 42. As a result, the first roller 41 and the second roller 42 rotate.

[0130] When the control unit (not shown) terminates the supply of power to the electromagnetic clutch C1, the electromagnetic clutch C1 returns to a state where it disconnects the transmission of driving force to the drive gear 50 and the first coupling 51.

[0131] <First clearance and second clearance> When the second coupling 52 shown in Figure 7(b) moves relative to the first bearing 61 in the other direction in the width direction, as shown in Figure 7(a), the abutment surface 52T of the second coupling 52 comes into contact with the first bearing 61 from one side in the width direction, thereby maintaining the state in which the insertion opening 75E side of the transmission member 70 fits into the shaft hole 61H.

[0132] When the fitting shaft portion 45 shown in Figure 7(a) moves relative to the fitting hole portion 75 in one direction in the width direction and is deeply inserted into the fitting hole portion 75, as shown in Figure 7(b), the abutment surface 44T comes into contact with the contact portion 76, thereby maintaining the state in which the engaging portion 73 fits into the engaged portion 43.

[0133] The second clearance CL2 is defined as the distance by which the engaging portion 73 can remain engaged with the engaged portion even when the fitting shaft portion 45 moves relative to the fitting hole portion 75 in the other direction in the width direction from the position shown in Figure 7(b), i.e., the clearance of the engaging portion 73 with respect to the engaged portion 43 in the width direction.

[0134] When the rotating shaft 41S shown in Figure 7(a) moves relative to the first restricting portion 91 and the second restricting portion 92 in one direction in the width direction, as shown in Figure 7(b), the C-type retaining ring 41C2 of the second protrusion 41S2 moves away from the second bearing 62 in one direction in the width direction, and the second restricted portion 62K1 of the second bearing 62 moves away from the second restricting surface 92K of the second restricting portion 92 in one direction in the width direction.

[0135] Then, the C-shaped retaining ring 41C1 of the first projection 41S1 contacts the first bearing 61 from the other side in the width direction, moving the first bearing 61 to one side in the width direction, and the first restricted portion 61K1 of the first bearing 61 contacts the first restricting surface 91K of the first restricting portion 91 from the other side in the width direction.

[0136] As a result, the first restricting unit 91 restricts the movement of the rotating shaft 41S in one direction in the width direction, with the first bearing 61 interposed.

[0137] When the rotating shaft 41S shown in Figure 7(b) moves relative to the first restricting portion 91 and the second restricting portion 92 in the other direction in the width direction, as shown in Figure 7(a), the C-type retaining ring 41C1 of the first protruding portion 41S1 moves away from the first bearing 61 in the other direction in the width direction, and the first restricted portion 61K1 of the first bearing 61 moves away from the first restricting surface 91K of the first restricting portion 91 in the other direction in the width direction.

[0138] Then, the C-shaped retaining ring 41C2 of the second protrusion 41S2 contacts the second bearing 62 from one side in the width direction, moving the second bearing 62 to the other side in the width direction, and the second restricted portion 62K1 of the second bearing 62 contacts the second restricting surface 92K of the second restricting portion 92 from one side in the width direction.

[0139] As a result, the second restricting unit 92 restricts the movement of the rotating shaft 41S in the width direction to the other side, with the second bearing 62 interposed.

[0140] As shown in Figure 7, the widthwise clearance with respect to the first restricting portion 91 and the second restricting portion 92 is defined as the first clearance CL1. The second clearance CL2 is greater than the first clearance CL1.

[0141] In this embodiment, the first clearance CL1 is described with reference to the positions of the other end edges of the C-type retaining rings 41C1 and 41C2 in Figures 7(a) and (b). However, the first clearance may also be described with reference to other parts, such as one end of the roller body 41A. As described above, the first clearance CL1 in the width direction of the rotating shaft 41S with respect to the first restricting portion 91 and the second restricting portion 92 of the frame 90 is via the first bearing 61 and the second bearing 62, and therefore is the clearance in the width direction including tolerances of the rotating shaft 41S, the first bearing 61, the second bearing 62, the frame 90, etc.

[0142] The length LT1 over which the contact surface 76F of the contact portion 76 contacts the flat surface 45F in the width direction is greater than the second clearance CL2.

[0143] <Effects and Effects> When the user carries the image forming apparatus 1 of Example 1, it may be accidentally dropped, causing an impact to be applied to the rotation axis 41S of the first roller 41.

[0144] In this case, when the rotating shaft 41S moves to one side in the width direction, the first restricting unit 91 restricts the movement of the rotating shaft 41S with the first bearing 61 interposed, as shown in Figure 7(b).

[0145] More specifically, the C-shaped retaining ring 41C1 of the first projection 41S1 contacts the first bearing 61 from the other side in the width direction, causing the first bearing 61 to move to one side in the width direction, and the first restricted portion 61K1 of the first bearing 61 contacts the first restricting surface 91K of the first restricting portion 91 from the other side in the width direction. As a result, the first restricting portion 91 restricts the movement of the rotating shaft 41S to one side in the width direction.

[0146] Furthermore, when the rotating shaft 41S moves to the other side in the width direction, the second restricting unit 92 restricts the movement of the rotating shaft 41S with the second bearing 62 interposed, as shown in Figure 7(a).

[0147] More specifically, the C-shaped retaining ring 41C2 of the second projection 41S2 abuts against the second bearing 62 from one side in the width direction, causing the second bearing 62 to move to the other side in the width direction, and the second restricted portion 62K1 of the second bearing 62 abuts against the second restricting surface 92K of the second restricting portion 92 from one side in the width direction. As a result, the second restricting portion 92 restricts the movement of the rotating shaft 41S to the other side in the width direction.

[0148] Here, the second clearance CL2 is larger than the first clearance CL1. This prevents the engaging portion 73 from colliding with the engaged portion 43 in the width direction when the first restricting portion 91 restricts the movement of the rotating shaft 41S to one side in the width direction, as shown in Figure 7(b). Also, as shown in Figure 7(a), this prevents the engaging portion 73 from colliding with the engaged portion 43 in the width direction when the second restricting portion 92 restricts the movement of the rotating shaft 41S to the other side in the width direction.

[0149] Therefore, the image forming apparatus 1 of Embodiment 1 can suppress the engagement portion 73 from disengaging from the engaged portion 43 when an impact is applied to the first roller 41, and as a result, it is possible to make it less likely for the transmission member 70 to come off the first protrusion 41S1 of the rotating shaft 41S.

[0150] Furthermore, in this image forming apparatus 1, as shown in Figure 7, the length LT1 over which the contact surface 76F of the contact portion 76 contacts the flat surface 45F in the width direction is greater than the second clearance CL2. With this configuration, during assembly, even if the engaging portion 73 moves in the width direction within the range of the second clearance CL2 relative to the engaged portion 43 after the fitting hole portion 75 has been fitted onto the fitting shaft portion 45 and the cylindrical shaft portion 44 by aligning the phase of the flat surface 45F and the contact surface 76F of the contact portion 76, the contact surface 76F of the contact portion 76 can be reliably maintained in contact with the flat surface 45F.

[0151] Furthermore, in this image forming apparatus 1, the engaging portion 73 is positioned on the opposite side of the axis X1 of the rotating shaft 41S from the flat surface 45F and the contact portion 76, when the fitting hole portion 75 is fitted onto the fitting shaft portion 45 and the cylindrical shaft portion 44. With this configuration, as shown in Figures 10 and 11, during assembly, by positioning the engaging portion 73 on the opposite side of the axis X1 of the rotating shaft 41S from the flat surface 45F, before fitting the fitting hole portion 75 onto the fitting shaft portion 45 and the cylindrical shaft portion 44, the phase of the flat surface 45F and the contact surface 76F of the contact portion 76, which is difficult to see, can be easily aligned. Furthermore, when fitting the fitting hole 75 onto the fitting shaft 45 and the cylindrical shaft 44, the tip of the engaging portion 73 initially rides onto the cylindrical outer surface of the fitting shaft 45. This allows the fitting hole 75 to be smoothly fitted onto the fitting shaft 45 and the cylindrical shaft 44 without being obstructed by the engaging portion 73.

[0152] Furthermore, in this image forming apparatus 1, as shown in Figure 13, the contact portion 76 has a hollowed-out shape having a pair of first portions 76A and 76B that are spaced apart from each other in the circumferential direction of the axis X1 of the rotating shaft 41S and extend in the width direction, and a second portion 76C that extends in the circumferential direction of the axis X1 and connects to the ends of both first portions 76A and 76B that are close to the insertion opening 75E. Let's assume that the second portion 76C is connected to the ends of the pair of first portions 76A and 76B that are farther from the insertion opening 75E. In this case, when the engaging portion 73 moves in the width direction within the range of the second clearance CL2 relative to the engaged portion 43, the second portion 76C of the contact portion 76 is more likely to separate from the flat surface 45F, and the contact portion 76 may become weaker against shear force. In this regard, with the above configuration, when the engaging portion 73 moves in the width direction within the range of the second clearance CL2 relative to the engaged portion 43, the second portion 76C of the contact portion 76 contacts the flat surface 45F with high reliability, so that the contact portion 76 does not become weak against shear force.

[0153] Furthermore, in the image forming apparatus 1, as shown in Figure 5, the rotating shaft 41S has a fitting shaft portion 45. The transmission member 70 has a fitting hole portion 75 that fits onto the fitting shaft portion 45, and a second coupling 52 that connects to a joint shaft 55 that rotates in response to the driving force of the motor M1. With this configuration, even if the position of the first roller 41 varies in the radial direction of the axis X1 of the rotating shaft 41S, the driving force of the motor M1 can be suitably transmitted to the rotating shaft 41S via the joint shaft 55 and the transmission member 70.

[0154] Furthermore, in the image forming apparatus 1, as shown in Figures 5 and 6, compression coil springs 49L and 49R bias the first bearing 61 and the second bearing 62 so that the first roller 41 presses the second roller 42 along the first direction DP1. The frame 90 has a first restricting section 91 and a second restricting section 92, and supports the first bearing 61 and the second bearing 62 so as to be movable in the first direction DP1. With this configuration, the first roller 41 and the second roller 42 can cooperate to suitably convey the sheet SH.

[0155] Furthermore, in the image forming apparatus 1, the drawer 80 is movable between a first position shown by a solid line in Figure 1 and a second position shown by a dashed line in Figure 1. The second roller 42 is supported by the drawer 80. With this configuration, although the second roller 42 comes into contact with and separates from the first roller 41 as the drawer 80 moves, the first roller 41 and the second roller 42 can be suitably positioned opposite each other when the drawer 80 moves to the first position.

[0156] Furthermore, in this image forming apparatus 1, the rotating shaft 41S has a first protrusion 41S1 and a second protrusion 41S2. The first bearing 61 supports the first protrusion 41S1. The second bearing 62 supports the second protrusion 41S2. The first restricting portion 91 restricts the movement of the rotating shaft 41S in one direction in the width direction with the first bearing 61 interposed. The second restricting portion 92 restricts the movement of the rotating shaft 41S in the other direction in the width direction with the second bearing 62 interposed. The first protrusion 41S1 has an engaged portion 43. With this specific configuration, the effects and advantages of the present invention can be reliably enjoyed.

[0157] (Example 2) As shown in Figure 14, the image forming apparatus of Example 2 employs a first regulating unit 291 and a second regulating unit 292 instead of the first regulating unit 91 and second regulating unit 92 of the image forming apparatus 1 of Example 1.

[0158] Furthermore, this image forming apparatus employs a flange 41F2 instead of the C-type retaining ring 41C2 according to Embodiment 1. The flange 41F2 protrudes radially outward from the outer surface of the second projection 41S2 near the roller body 41A and extends around the axis X1 in a circumferential direction.

[0159] The other components of Example 2 are the same as those of Example 1. Therefore, components identical to those of Example 1 are denoted by the same reference numerals, and their descriptions are omitted or simplified.

[0160] The first regulating section 291 has a first regulating section body 291A and a first regulating projection 291K.

[0161] The first restricting section body 291A has substantially the same configuration as the first restricting section 91 according to Embodiment 1, but does not have a first restricting surface 91K. The first restricted sections 61K1 and 61K2 surround the first restricting section body 291A. As a result, the first restricting section body 291A supports the first bearing 61 so that it can move in the first direction DP1.

[0162] The first regulating projection 291K protrudes from the first regulating body 291A at a position separated from it in the other direction in the width direction, and approaches the first protruding portion 41S1. The tip of the first regulating projection 291K is located between the first bearing 61 and the C-type retaining ring 41C1.

[0163] The second restricting section 292 has a second restricting section body 292A and a second restricting projection 292K.

[0164] The second restricting section body 292A has substantially the same configuration as the second restricting section 92 according to Embodiment 1, but does not have a second restricting surface 92K. The second restricted sections 62K1 and 62K2 surround the second restricting section body 292A. As a result, the second restricting section body 292A supports the second bearing 62 so that it can move in the first direction DP1.

[0165] The second restricting projection 292K protrudes from the second restricting body 292A at a position separated from it in one direction in the width direction, and approaches the second projection 41S2. The tip of the second restricting projection 292K is located between the second bearing 62 and the flange 41F2.

[0166] When the rotating shaft 41S shown in Figure 14(a) moves relative to the first restricting portion 91 and the second restricting portion 92 in one direction in the width direction, the flange 41F2 of the second protrusion 41S2 moves away from the second restricting projection 292K of the second restricting portion 292 in one direction in the width direction, as shown in Figure 14(b).

[0167] Then, the C-shaped retaining ring 41C1 of the first protruding portion 41S1 abuts against the first restricting projection 291K of the first restricting portion 291 from the other side in the width direction.

[0168] As a result, the first restricting unit 291 directly restricts the movement of the rotating shaft 41S in one direction in the width direction.

[0169] When the rotating shaft 41S shown in Figure 14(b) moves relative to the first restricting portion 91 and the second restricting portion 92 in the other direction in the width direction, as shown in Figure 14(a), the C-shaped retaining ring 41C1 of the first protrusion 41S1 moves away from the first restricting projection 291K of the first restricting portion 291 in the other direction in the width direction.

[0170] Then, the flange 41F2 of the second protrusion 41S2 abuts against the second restricting projection 292K of the second restricting portion 292 from one side in the width direction.

[0171] As a result, the second restricting unit 292 directly restricts the movement of the rotating shaft 41S in the width direction toward the other side.

[0172] As shown in Figure 14, the widthwise clearance with respect to the first restricting portion 291 and the second restricting portion 292 is defined as the first clearance CL3. The second clearance CL2 is greater than the first clearance CL3.

[0173] <Effects and Effects> When the image forming apparatus of Example 2 is being carried by the user, it may be accidentally dropped, causing an impact to be applied to the rotation axis 41S of the first roller 41.

[0174] In this case, when the rotating shaft 41S moves in one direction in the width direction, the first restricting projection 291K of the first restricting part 291 directly restricts the movement of the rotating shaft 41S, as shown in Figure 14(b).

[0175] Furthermore, when the rotating shaft 41S moves to the other side in the width direction, the second restricting projection 292K of the second restricting section 292 directly restricts the movement of the rotating shaft 41S, as shown in Figure 14(a).

[0176] Here, the second clearance CL2 is larger than the first clearance CL3. As a result, as shown in Figure 14(b), when the first restricting projection 291K of the first restricting part 291 restricts the movement of the rotation axis 41S in one direction in the width direction, it is possible to suppress the engagement part 73 from colliding with the engaged part 43 in the width direction. Also, as shown in Figure 14(a), when the second restricting projection 292K of the second restricting part 92 restricts the movement of the rotation axis 41S in the other direction in the width direction, it is possible to suppress the engagement part 73 from colliding with the engaged part 43 in the width direction.

[0177] Therefore, the image forming apparatus of Example 2, like the image forming apparatus 1 of Example 1, can suppress the engagement portion 73 from disengaging from the engaged portion 43 when an impact is applied to the first roller 41, and as a result, it is possible to make it less likely for the transmission member 70 to come off the first protrusion 41S1 of the rotating shaft 41S.

[0178] Although the present invention has been described above in reference to Examples 1 and 2, it goes without saying that the present invention is not limited to Examples 1 and 2, and can be applied with appropriate modifications without departing from its spirit.

[0179] In Examples 1 and 2, the sheet transport device of the present invention was embodied as an image forming apparatus 1 equipped with an image forming function, but the present invention is not limited to this configuration. For example, the configuration of the present invention may be applied to an image reading device equipped only with an image reading function, or to a multifunction device equipped with both an image forming function and an image reading function.

[0180] In Examples 1 and 2, the transmission member 70 has a second coupling 52, but the present invention is not limited to this configuration. For example, a configuration in which the transmission member has a gear is also included in the present invention.

[0181] In Examples 1 and 2, the engaging portion 73 of the transmission member 70 has an elastically deformable cantilever beam and a claw formed at its tip, and the engaged portion 43 of the rotating shaft 41S is a recess that engages with the claw. However, the present invention is not limited to this configuration. For example, the present invention also includes a configuration in which the engaging portion of the transmission member has an elastically deformable cantilever beam and a recess formed at its tip, and the engaged portion of the rotating shaft has a projection that engages with the recess. [Explanation of Symbols]

[0182] 1…Sheet transport device (image forming apparatus) 41S...rotating axis, SH...seat 41...First roller, 70...Transmission member 61, 62...Bearings (61...First bearing, 62...Second bearing) 91, 92, 291, 292... Regulatory Departments (91, 291...First Regulatory Department, 92, 292...Second Regulatory Department) 43...Engaged part, 73...Engaging part CL1, CL3...First clearance, CL2...Second clearance 45F...Flat surface of the mating shaft, 45...Matching shaft, 75...Matching hole 75C...Inner circumferential surface of the fitting hole, 76...Contact portion LT1... The length over which the contact portion contacts the flat surface in the axial direction. X1...Axis of the rotating shaft, 75E...Insertion port 76A, 76B...first part, 76C...second part M1...Motor, 55...Joint Shaft 52... Coupling (Second Coupling) 42...Second roller, DP1...First direction 49L, 49R... Biasing member (compression coil spring) 90...frame, 3G...toner storage compartment 80...drawer, 9...main unit 41S1...first protrusion, 41S2...second protrusion

Claims

1. A first roller having a rotating shaft extending in the axial direction for conveying a sheet, A bearing that supports the aforementioned rotating shaft, A transmission member that rotates integrally with the aforementioned rotating shaft and transmits driving force to the aforementioned rotating shaft, A restricting unit that restricts the axial movement of the rotating shaft directly or through the bearing, Equipped with, The rotating shaft has an engaged portion, The transmission member has an engaging portion that engages with the engaged portion and restricts the transmission member from disengaging from the rotation shaft in the axial direction. The axial clearance of the rotating shaft with respect to the restricting portion is defined as the first clearance. If the axial clearance of the engaging portion with respect to the engaged portion is defined as the second clearance, A sheet conveying device characterized in that the second clearance is larger than the first clearance.

2. The rotating shaft has a cylindrical outer surface, a part of which is a flat surface extending in the axial direction, and a fitting shaft portion that protrudes in one direction in the axial direction. The transmission member has a fitting hole that fits onto the fitting shaft, and a contact portion formed on the inner circumferential surface of the fitting hole, which abuts against the flat surface and restricts the transmission member from rotating relative to the rotation shaft. The sheet conveying device according to claim 1, wherein the length over which the contact portion contacts the flat surface in the axial direction is greater than the second clearance.

3. The sheet conveying device according to claim 2, wherein the engaging portion is located on the opposite side of the flat surface and the contact portion with respect to the axis of the rotating shaft, with respect to the axis of the rotating shaft, in a state in which the fitting hole portion is externally fitted onto the fitting shaft portion.

4. The fitting hole portion has an insertion opening into which the fitting shaft portion is inserted. The sheet conveying device according to claim 2, wherein the contact portion has a hollowed-out shape having a pair of first portions that are spaced apart from each other in the circumferential direction of the axis of the rotating shaft and each extends in the axial direction, and a second portion that extends in the circumferential direction and connects to the ends of both first portions near the insertion opening.

5. A motor that generates driving force, A joint shaft extending in the axial direction and rotating in response to the driving force of the motor, Equipped with, The rotating shaft has a fitting shaft portion that protrudes in one direction in the axial direction, The sheet conveying device according to any one of claims 1 to 4, wherein the transmission member has a fitting hole that fits onto the fitting shaft and a coupling that connects to the joint shaft.

6. Opposite the first roller is a second roller that conveys the sheet, A biasing member that biases the bearing such that the first roller presses the second roller along a first direction, A frame having the aforementioned restricting portion and supporting the bearing so as to be movable in the first direction, The sheet conveying device according to claim 5, comprising:

7. A drawer that detachably supports a toner storage unit for forming an image on a sheet conveyed by the first roller and the second roller, A device body that houses the drawer in a first position and supports the drawer so that it can move from the first position, Equipped with, The drawer is movable between the first position and the second position, in which at least a portion of it is located outside the main body of the device and the toner storage section is replaceable. The sheet conveying device according to claim 6, wherein the second roller is supported by the drawer.

8. The rotating shaft has a first projection that protrudes in one direction in the axial direction and a second projection that protrudes in the other direction in the axial direction. The bearing comprises a first bearing that supports the first protrusion and a second bearing that supports the second protrusion. The restricting unit restricts the movement of the rotating shaft in the axial direction to one side, either directly or through the first bearing, and restricts the movement of the rotating shaft in the axial direction to the other side, either directly or through the second bearing. The sheet conveying device according to any one of claims 1 to 4, wherein the first protrusion has the engaged portion.

Images