Sheet conveying device, image reading device, and image forming device

Abstract

To reduce conveying failures.SOLUTION: A sheet conveying device includes: a support member provided with a guide surface; a roller unit having a roller member, a roller shaft, and a holder member, and attached to and detached from the support member; a drive shaft provided on the support member; a coupling member for connecting the drive shaft and the roller shaft; and a drive source for supplying driving force to the roller shaft via the drive shaft and the coupling member. At least a part of the coupling member is exposed to a conveying path, and an outer peripheral part of the coupling member is provided with a rib which extends in an inclined direction away from the center of the roller member in a sheet width direction perpendicular to a sheet conveying direction toward downstream of the sheet conveying direction, when the coupling member is viewed from the conveying path.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a sheet conveying device that conveys a sheet, an image reading device that reads an image from a sheet, and an image forming apparatus that forms an image on a recording material. [Background technology]

[0002] Patent Document 1 describes an automatic document feeder in which rollers can be replaced by attaching and detaching a transport roller unit having a pickup roller and a paper feed roller to and from a paper feed cover. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-229538 Summary of the Invention [Problem to be solved by the invention]

[0004] In the above document, a part of the coupling that connects the drive shaft supported by the paper feed cover and the paper feed roller shaft of the conveyance roller unit is exposed to the conveyance path, and the outer surface of the coupling has a recess extending in the sheet width direction, so there is a possibility that the leading edge of the conveyed sheet may get caught in the recess of the coupling, causing conveyance problems.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a sheet conveying device, an image reading device, and an image forming apparatus that are capable of reducing the occurrence of conveyance failures. [Means for solving the problem]

[0006] One aspect of the present invention is a sheet conveying device comprising: a support member provided with a guide surface that forms a sheet conveying path; a roller member that conveys a sheet through the conveying path; a roller shaft that supports the roller member; and a holder member that holds the roller member and the roller shaft, the roller unit being detachable from the support member; a drive shaft provided on the support member; a coupling member that connects the drive shaft and the roller shaft; and a drive source that supplies driving force to the roller shaft via the drive shaft and the coupling member, wherein at least a portion of the coupling member is exposed to the conveying path, and when the coupling member is viewed from the conveying path, the outer periphery of the coupling member is provided with a rib that extends in an inclined direction away from the center of the roller member in the sheet width direction perpendicular to the sheet conveying direction toward downstream in the sheet conveying direction. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a sheet conveying device, an image reading device, and an image forming apparatus that can reduce the occurrence of conveyance failures. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic diagram of an image forming apparatus according to an embodiment. [Figure 2] FIG. 1 is a perspective view of an image reading apparatus according to an embodiment. [Figure 3] 1 is a schematic diagram of an image reading apparatus according to an embodiment. [Figure 4] FIG. 2 is a diagram showing a conveying roller unit according to the embodiment. [Figure 5] FIG. 2 is a view of the opening / closing cover according to the embodiment, seen from the document transport path side. [Figure 6] FIG. 3 is a cross-sectional view of the opening / closing cover according to the embodiment. [Figure 7] FIG. 4 is a perspective view of a coupling member according to the embodiment. [Figure 8] 3A to 3D are explanatory views of a coupling member according to an embodiment. [Figure 9]5A to 5C are diagrams illustrating a method for attaching and detaching a conveying roller unit according to the embodiment. [Figure 10] 5A to 5C are diagrams illustrating a method for attaching and detaching a conveying roller unit according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0010] First, an image forming apparatus 100 and an image reading apparatus 101 according to one embodiment will be described with reference to FIGS. 1 to 3. The image forming apparatus 100 is a color multifunction peripheral equipped with a tandem intermediate transfer type image forming unit 120 as an image forming means. Note that the image forming apparatus 100 is merely one example of an image forming apparatus to which the technology according to the present disclosure can be applied. The "image forming apparatus" may be a single-function printer or a large commercial printing machine. Furthermore, the image forming means may be a direct transfer type, and is not limited to an electrophotographic type, and may be, for example, an inkjet type printing mechanism.

[0011] 1, the image forming apparatus 100 includes an image forming apparatus main body 104 and an image reading device 101 disposed above the image forming apparatus main body 104. Inside the image forming apparatus main body 104, an image forming unit 120, a feeding cassette 105 that stores recording material P, a feeding roller 106 that feeds the recording material P, and the like are disposed.

[0012] Image forming section 120 includes four process units 111, 112, 113, and 114 (image forming stations), and laser scanners 107, 108, 109, and 110 as exposure means. Image forming section 120 also includes an intermediate transfer belt 115, a secondary transfer roller 116, and a fixing unit 118.

[0013] Each of the process units 111-114 has a photosensitive drum as an image carrier, a charging unit acting on the photosensitive drum, a developing unit, and a cleaning unit. An intermediate transfer belt 115 as an intermediate transfer member is stretched over multiple rollers. The four process units 111-114 are arranged side by side along the intermediate transfer belt 115. A transfer unit (secondary transfer unit) where a toner image is transferred is formed as a nip between a secondary transfer roller 116 and the intermediate transfer belt 115.

[0014] The fixing unit 118 includes a heating member such as a fixing roller, a pressure member such as a pressure roller, and a heat source such as a halogen lamp for heating the heating member. A fixing nip is formed between the heating member and the pressure member.

[0015] An overview of the image forming operation, which is a series of operations by which the image forming apparatus 100 forms an image on the recording material P, will be described. For example, when a user presses a copy execution button with an original document set in the image reading device 101, the control unit of the image forming apparatus 100 starts an image reading operation by the image forming apparatus main body 104 and an image forming operation by the image forming apparatus main body 104. The control unit forms an image on the recording material P based on image information acquired by causing the image reading device 101 to execute the image reading operation. The configuration of the image reading device 101 and the image reading operation will be described later.

[0016] During image formation, the photosensitive drums of each process unit 111-114 and the intermediate transfer belt 115 are rotated. The charging units uniformly charge the surfaces of the photosensitive drums. The laser scanners 107-110 are driven based on image data obtained by breaking down image information into yellow, magenta, cyan, and black components, and irradiate the photosensitive drums with light. This exposes the photosensitive drums, forming electrostatic latent images on their surfaces. The developing units develop the electrostatic latent images using toner as a developer. As a result, single-color toner images of yellow, magenta, cyan, and black are formed on the four photosensitive drums. These single-color toner images are primarily transferred onto the intermediate transfer belt 115 so that they overlap each other, forming a full-color toner image (hereinafter simply referred to as the toner image) on the intermediate transfer belt 115.

[0017] In parallel with the formation of the toner image, a feeding roller 106 feeds recording material P one sheet at a time from a feeding cassette 105 toward a secondary transfer portion. At the secondary transfer portion, a toner image is secondarily transferred from an intermediate transfer belt 115 to the recording material P by applying a voltage to a secondary transfer roller 116. After passing through the secondary transfer portion, the recording material P is sent to a fixing unit 118, where the toner image is heated and pressed. This fixes the toner image to the recording material P. After passing through the fixing unit 118, the recording material P is discharged to the outside of the image forming apparatus main body 104 and stacked on a discharge tray 119.

[0018] (Image reader) Next, the image reading device 101 will be described with reference to Figures 1 to 3. The image reading device 101 has a reader 103 and an automatic document feeder (hereinafter referred to as ADF) 102. The reader 103 is attached to the top of an image forming apparatus main body 104. The ADF 102 is supported by 103 and is provided so as to be openable and closable relative to the reader 103. The ADF 102 is an example of a sheet transport device that transports sheets (documents).

[0019] 2 and 3, the reader 103 has a front side reading unit 306 and a flow reading glass 312. The ADF 102 also has a document tray 200, an ADF main body 316, an opening / closing cover 315, a separation guide 317, an ejection tray 201, a back side reading unit 307, and a flow reading glass 313. The ADF 102 also has a pickup roller 43, a feed roller 44, a separation roller 301, a pair of pull-out rollers 302, a first pair of read rollers 303, a second pair of read rollers 304, and a pair of ejection rollers 305. The pickup roller 43 and the feed roller 44 are part of a transport roller unit 40, which will be described later.

[0020] The front surface reading unit 306 and the back surface reading unit 307 are examples of reading means for reading image information from a sheet. In this embodiment, the front surface reading unit 306 is a CCD-type image sensor unit, and the back surface reading unit 307 is a CIS-type image sensor unit. The front surface reading unit 306 has a sensor board 309 on which a light receiving element is arranged, a light source 310 that irradiates the document with light, and a plurality of mirrors 308 that constitute a reduction optical system that forms an optical image of the document on the light receiving surface of the sensor board. The back surface reading unit 307 has a CMOS sensor board, a light source that irradiates the document with light, and a 1:1 optical system that forms an optical image of the document on the light receiving surface of the sensor board.

[0021] Of the conveyance rollers provided in the ADF 102, the pickup roller 43, the feed roller 44, and one of the pair of pull-out rollers 302 are supported by an open / close cover 315. The other roller of the pair of pull-out rollers 302, the first pair of read rollers 303, the second pair of read rollers 304, and the pair of discharge rollers 305 are supported by an ADF main body 316. In addition, the separation roller 301 is supported by a separation guide 317 attached to the ADF main body 316.

[0022] The ADF main body 316 is a first unit (main body unit) that can be opened and closed relative to the reader 103. The document tray 200 and the discharge tray 201 are supported by the ADF main body 316. The opening and closing cover 315 is a second unit (opening and closing member, opening and closing unit) that is supported by the ADF main body 316 so as to be movable (openable and closable).

[0023] Open-close cover 315 has guide surface 315g that, together with a guide surface provided on the main body side of ADF main body 316, forms at least a part of a transport path (document transport path CP) through which the document passes. Open-close cover 315 is movable (openable and closable) between a closed position where it is closed to form document transport path CP and an open position where document transport path CP is open. Open-close cover 315 also has exterior surface 315u that forms a part of the top surface of ADF 102 when open-close cover 315 is in the closed position. Open-close cover 315 of this embodiment rotates around a center line extending in the sheet width direction, using a shaft provided at the left end of open-close cover 315 in FIG. 3 as a fulcrum.

[0024] Pickup roller 43 is a pickup member that picks up a document from document tray 200, which serves as a placement section on which documents are placed. Feed roller 44 is a feeding member that feeds the document fed from document tray 200. Separation roller 301 comes into contact with feed roller 44 when open / close cover 315 is closed, forming a separation nip.

[0025] Separation roller 301 is an example of a separating member that separates sheets by applying frictional force to the sheets. Separation roller 301 may be a roller member supported via a torque limiter on a shaft member fixed to ADF main body 316. Separation roller 301 may also be a retard drive roller that receives a driving force via a torque limiter in a direction (clockwise direction in FIG. 3) opposite to the document movement direction (sheet conveying direction Df) in the separation nip. Alternatively, separation roller 301 may be replaced by a pad-shaped elastic member (rubber pad) that comes into contact with feed roller 44 as the separating member.

[0026] The image reading device 101 is capable of performing an image reading operation (flow-reading operation) in which the front surface reading unit 306 and the back surface reading unit 307 read image information from the originals while the ADF 102 transports the originals one sheet at a time. When the image reading operation starts, the pickup roller 43 rotates while in contact with the topmost original on the original tray 200, and feeds the original from the original tray 200. The feed roller 44 further transports the fed original in the sheet transport direction Df. The separation roller 301 applies a frictional force to the original in the separation nip in the direction opposite to the sheet transport direction Df. When multiple originals enter the separation nip, the separation roller 301 prevents any originals other than the one in contact with the feed roller 44 from passing through the separation nip. As a result, the originals pass through the separation nip in a single separated state.

[0027] The document that has passed through the separation nip is transported in this order by a pair of pull-out rollers 302, a first pair of read rollers 303, and a second pair of read rollers 304. During this process, a front surface reading unit 306 and a back surface reading unit 307 optically scan both sides of the document through flow-reading glasses 312 and 313 and convert the scanned images into electronic signals. This allows image information to be acquired as electronic image data. The document from which the image information has been read is discharged from the ADF main body 316 by a pair of discharge rollers 305 and placed on the discharge tray 201.

[0028] The image reading device 101 can also read image information from a stationary original placed on the reader 103. In this case, the user opens the ADF 102 and places the original on the platen glass of the reader 103, and then closes the ADF 102 to instruct the reader 103 to execute reading. Then, the front surface reading unit 306 moves in the sub-scanning direction to optically scan the original and acquire image information.

[0029] (Transport roller unit) The conveying roller unit 40 will be described with reference to Figure 4. In the following description, the movement direction of the document conveyed by the pickup roller 43 and the feed roller 44 is referred to as the sheet conveying direction Df. The direction perpendicular to the sheet conveying direction Df and along one side of the document is referred to as the sheet width direction Dw. The sheet width direction Dw is substantially parallel to the directions of the rotation axes of the feed roller 44, the feed roller shaft 46, the drive shaft 68, and the coupling member 66.

[0030] 4, the transport roller unit 40 has a pickup roller 43, a feed roller 44, a holder member 45, a feed roller shaft 46, and a swing arm 41. The feed roller 44 is an example of a roller member that transports a sheet through the transport path (document transport path CP). The feed roller shaft 46 is an example of a roller shaft that supports the roller member. The transport roller unit 40 is a replaceable unit that is detachably attached to the opening / closing cover 315, which serves as a support member.

[0031] Pickup roller 43 is rotatably supported by swing arm 41. Swing arm 41 is supported by holder member 45 and can swing relative to holder member 45 around the rotation axis of feed roller 44. By swinging swing arm 41, pickup roller 43 can move (move up and down) so as to come into contact with and separate from the document on document tray 200.

[0032] The feed roller 44 is attached to the feed roller shaft 46 via a one-way clutch. The feed roller shaft 46 receives a driving force from a coupling member 66 (FIG. 5) provided in the open / close cover 315, which will be described later. The driving force input to the feed roller shaft 46 is transmitted to the feed roller 44 via the one-way clutch, causing the feed roller 44 to rotate in a direction along the sheet conveyance direction Df. In other words, the one-way clutch prevents the feed roller 44 from rotating in a direction opposite to the sheet conveyance direction Df, and allows the feed roller shaft 46 and the feed roller 44 to rotate integrally. On the other hand, when a document passes through the separation nip with the input of the driving force to the feed roller shaft 46 stopped, the one-way clutch allows the feed roller 44 to rotate relative to the feed roller shaft 46 so as to idle in the direction along the sheet conveyance direction Df.

[0033] The feed roller shaft 46 is held by the holder member 45 via a first bearing portion 46a and a second bearing portion 46b. The feed roller shaft 46 is rotatable around a rotation axis in the sheet width direction Dw. The first bearing portion 46a rotatably supports one end of the feed roller shaft 46 in the sheet width direction Dw, and the second bearing portion 46b rotatably supports the other end of the feed roller shaft 46 in the sheet width direction Dw.

[0034] A spring pin 47 is provided at one end of the feed roller shaft 46 as a first engagement portion (drive input portion) that engages with the coupling member 66. The spring pin 47 will be described later.

[0035] The holder member 45 is provided with a spacing arm 55 as an elastically deformable operating part. The spacing arm 55 is configured so that it is elastically deformed in the direction of arrow B when the user pinches and operates it to attach or detach the transport roller unit 40. The spacing arm 55 is provided with a latched part 55a that is latched by a spacing arm holding part 76 (described later) that is provided on the open / close cover 315.

[0036] The feed roller shaft 46 and the pickup roller 43 are connected via a gear train (43a, 48, 49). Specifically, an input gear 43a is formed at the end of the pickup roller 43. The input gear 43a is connected to a drive gear 49 arranged coaxially with the feed roller shaft 46 via a plurality of idler gears 48 rotatably supported on the swing arm 41. The drive gear 49 is connected to the feed roller shaft 46 via a one-way clutch. This one-way clutch transmits the driving force input to the feed roller shaft 46 to the pickup roller 43, causing the pickup roller 43 to rotate in the sheet conveying direction Df. Meanwhile, this one-way clutch allows the pickup roller 43 to rotate idly in the sheet conveying direction Df when the input of the driving force to the feed roller shaft 46 is stopped.

[0037] The swing arm 41 and the feed roller shaft 46 are connected via a spring clutch attached to the outer periphery of the feed roller shaft 46. When a driving force that rotates the feed roller 44 in a direction along the sheet conveying direction Df is input to the feed roller shaft 46, a downward torque acts on the swing arm 41 via the spring clutch, causing the swing arm 41 to descend and bring the pickup roller 43 into contact with the document. When the input of the driving force to the feed roller shaft 46 is stopped, the swing arm 41 rises due to the biasing force of a biasing member (return spring) provided between the swing arm 41 and the holder member 45, for example. Note that instead of the spring clutch, an independent drive source such as a solenoid may be used to raise and lower the swing arm 41.

[0038] (Support structure of the transport roller unit) Next, the support structure of the transport roller unit 40 will be described with reference to Fig. 5. Fig. 5 is a view of the openable cover 315 from the guide surface 315g side with the transport roller unit 40 removed.

[0039] The openable cover 315 is provided with a bearing support portion 65 , a bearing clamping portion 64 , a spacing arm holding portion 76 , a protrusion 77 , and a recess 78 .

[0040] The recess 78 has a recessed shape recessed from the guide surface 315g. When the transport roller unit 40 is attached to the open / close cover 315, at least a portion of the transport roller unit 40 is accommodated in the recess 78. The bearing support portion 65, the bearing clamping portion 64, and the protrusion 77 are disposed in the recess 78. The separation arm holding portion 76 has a canopy-like shape formed on the periphery of the recess 78.

[0041] The bearing support portion 65 supports the first bearing portion 46a of the conveying roller unit 40 (see also FIG. 10). The first bearing portion 46a is formed in a substantially arcuate (semicircular) shape when viewed in the sheet width direction Dw. The protrusion portion 77 is an engaging portion that engages with a groove shape provided on the back surface of the holder member 45 (the surface on the far side of the paper in FIG. 4). In this embodiment, two protrusion portions 77 are arranged side by side in the sheet width direction Dw. In this embodiment, the bearing support portion 65 engages with the first bearing portion 46a at one end side in the sheet width direction Dw, and the protrusion portion 77 engages with the groove portion of the holder member 45 at a position different from the bearing support portion 65 in the sheet width direction Dw. This determines the position of the conveying roller unit 40 in the sheet conveying direction Df and the sheet width direction Dw.

[0042] The bearing clamping portion 64 is provided adjacent to the bearing support portion 65 in the sheet width direction Dw. When the conveying roller unit 40 is attached to the open-close cover 315, the bearing clamping portion 64 clamps the first bearing portion 46a. Like the bearing support portion 65, the bearing clamping portion 64 has an arc shape and is elastically deformable. The bearing clamping portion 64 is composed of two arms, and the first bearing portion 46a is held in the space formed between the two arms. The width of the inlet of the bearing clamping portion 64 is narrower than the outer diameter of the first bearing portion 46a. When the conveying roller unit 40 is attached to the open-close cover 315, the elastic deformation of the bearing clamping portion 64 presses the first bearing portion 46a into the bearing clamping portion 64. When the conveying roller unit 40 is removed from the open-close cover 315, the elastic deformation of the bearing clamping portion 64 allows the first bearing portion 46a to be released from the bearing clamping portion 64.

[0043] The spacing arm holding portion 76 is disposed near the bearing clamping portion 64 and is formed by a part of the guide surface 315g. The spacing arm holding portion 76 locks the locked portion 55a (FIG. 4) of the spacing arm 55, which is part of the transport roller unit 40, thereby restricting the transport roller unit 40 from moving in a direction to separate from the recess 78. Furthermore, when the user operates the spacing arm 55, the elastic deformation of the spacing arm 55 causes the locked portion 55a to move in the direction of arrow B, allowing it to separate from the spacing arm holding portion 76.

[0044] (coupling component) The coupling member 66 and its surrounding structure will be described mainly with reference to Fig. 6. Fig. 6 is a cross-sectional view of the openable cover 315 taken along line AA in Fig. 5.

[0045] 6, the openable cover 315 is provided with a coupling member 66, a drive shaft 68, and a feeding gear 69. The drive shaft 68 is a shaft member that extends in the sheet width direction Dw.

[0046] A feeding gear 69 is attached to one end of a drive shaft 68 in the sheet width direction Dw, and a coupling member 66 is attached to the other end of the drive shaft 68 in the sheet width direction Dw. The drive shaft 68, the coupling member 66, and the feeding gear 69 rotate integrally around an axis extending in the sheet width direction Dw.

[0047] The feed gear 69 is connected to a feed motor 72 via a drive transmission mechanism such as a gear train or a belt. The feed motor 72 is a drive source that supplies driving force to the transport roller unit 40 via a drive shaft 68 and a coupling member 66. The feed motor 72 is disposed in the ADF main body 316. The drive shaft 68 is rotatably supported with respect to the open-close cover 315 by bearings 70 and 71 fixed to the open-close cover 315. Most of the drive shaft 68 is disposed in the space between a guide surface 315g and an exterior surface 315u of the open-close cover 315.

[0048] The coupling member 66 is configured to connect the drive shaft 68 and the feed roller shaft 46 of the conveying roller unit 40 when the conveying roller unit 40 is attached to the open / close cover 315. The coupling member 66 in this embodiment is a drive output part that transmits driving force to the conveying roller unit 40.

[0049] In this embodiment, a spring pin 47 (FIG. 4) is provided as a first engagement portion at one end of the feed roller shaft 46. The end of the feed roller shaft 46 including the spring pin 47 is a drive input portion to which a drive force is input via a coupling member 66.

[0050] The spring pin 47 is attached to a hole in the feed roller shaft 46 so as to protrude outward on both sides from the outer surface of the feed roller shaft 46 in a direction perpendicular to the sheet width direction Dw. The drive shaft 68 and the feed roller shaft 46 are connected by the spring pin 47 engaging with a first cross groove 66a (FIG. 7) described below on the inside of the coupling member 66. Note that the "first engaging portion" is not limited to the spring pin 47, and may be, for example, a key-shaped portion formed integrally with the feed roller shaft 46.

[0051] As shown in Figure 6, the coupling member 66 is fixed to the drive shaft 68 via a parallel pin 74 serving as a second engagement portion. The parallel pin 74 is inserted into a through hole provided in the drive shaft 68 and protrudes from the outer surface of the drive shaft 68 in a direction perpendicular to the sheet width direction Dw. The parallel pin 74 engages with a second cross groove 66b (Figure 8(c)), which will be described later, on the inside of the coupling member 66, thereby connecting the coupling member 66 and the drive shaft 68 so that they cannot rotate relative to each other. Note that the "second engagement portion" is not limited to the parallel pin 74, and may be, for example, a key-shaped portion formed integrally with the drive shaft 68.

[0052] 5 and 6, when opening / closing cover 315 is viewed from the side of document transport path CP, at least a portion of coupling member 66 is not covered by guide surface 315g. In other words, at least a portion of coupling member 66 is exposed to document transport path CP. In this embodiment, coupling member 66 is exposed inside notch 78a of guide surface 315g that is continuous with recess 78 provided in opening / closing cover 315. Note that the entire coupling member 66 may be exposed when viewed from the side of document transport path CP.

[0053] (Coupling shape) The shape of the coupling member 66 will be described in detail with reference to Fig. 7 and Figs. 8(a) to 8(d). Fig. 7 is a perspective view of the coupling member 66. Fig. 8(a) is a view of the coupling member 66 as seen from a direction perpendicular to the axial direction. Fig. 8(b) is a view of the coupling member 66 as seen from the left side of Fig. 8(a) in the sheet width direction Dw. Fig. 8(c) is a cross-sectional view of the coupling member 66 taken along line BB in Fig. 8(a). Fig. 8(d) is a cross-sectional view of the coupling member 66 taken along line CC in Fig. 8(a).

[0054] In the following description, the direction of the rotation axis of the coupling member 66 is simply referred to as the axial direction. The axial direction of the coupling member 66 is substantially the same as the sheet width direction Dw when the coupling member 66 is attached to the ADF 102.

[0055] As shown in Figures 7 and 8(a) to (d), the coupling member 66 is a substantially cylindrical member having a first cross groove 66a, a second cross groove 66b, a non-circular outer surface 66c, a rib 66d, and a shaft hole 66e.

[0056] The non-circular outer surface 66c and the rib 66d are formed on the outer periphery of the coupling member 66. The shaft hole 66e, the first cross groove 66a, and the second cross groove 66b are formed on the inner periphery of the coupling member 66.

[0057] The shaft hole 66e is a hole through which the drive shaft 68 is inserted. The inner peripheral surface of the shaft hole 66e of the coupling member 66 is supported by the outer peripheral surface of the drive shaft 68. In this embodiment, the shaft hole 66e and the first and second cross grooves 66a and 66b are continuous and penetrate the inside of the coupling member 66 in the axial direction.

[0058] A part of the shaft hole 66e is formed as a large diameter portion 66e1 (FIG. 8(d)) having an inner diameter wider than the outer diameter of the drive shaft 68. The large diameter portion 66e1 can accommodate a biasing member (coil spring) that biases the coupling member 66 to the left in FIG. 6 in the sheet width direction Dw, thereby pressing the coupling member 66 against the end of the feed roller shaft 46.

[0059] The first cross groove 66a has a groove shape that, when viewed in the axial direction, spreads out in a cross shape from the center of the coupling member 66. The first cross groove 66a is a first groove portion that engages with the spring pin 47 (first engagement portion) described above when the conveying roller unit 40 is attached to the open-close cover 315.

[0060] The second cross groove 66b has a groove shape that, when viewed in the axial direction, spreads out in a cross shape from the center of the coupling member 66. The second cross groove 66b is a second groove portion that engages with the aforementioned parallel pin 74 (FIG. 6) provided on the end of the drive shaft 68.

[0061] The non-circular outer surface 66c is a non-circular outer surface formed in a shape (approximately cross-shaped in the axial direction) that follows the shape of the first cross groove 66a and the second cross groove 66b, which are cross-shaped when viewed in the axial direction. In this embodiment, the non-circular outer surface 66c includes a plurality of ridges 66c1 that are located on extensions of the first cross groove 66a and extend in the axial direction, and recesses 66c2 formed between adjacent ridges 66c1 (FIG. 7). Each ridge 66c1 is located on an extension of the second cross groove 66b. The recesses 66c2 are recessed toward the center of the coupling member 66 relative to the ridges 66c1. Furthermore, the non-circular outer surface 66c in this embodiment is formed by four ridges 66c1 and four recesses 66c2 that are alternately arranged in the rotational direction of the coupling member 66. The distance from the center of the coupling member 66 (the rotation axis of the feed roller shaft 46) to the ridge 66c1 is greater than the distance from the center of the coupling member 66 to the bottom of the recess 66c2 (the center of each recess 66c2 in the rotation direction of the coupling member 66).

[0062] Note that, instead of the first cross groove 66a, an I-shaped groove capable of engaging with the spring pin 47 may be formed. In that case, the non-circular outer surface 66c on the outer periphery side of the first cross groove 66a is formed in a substantially I-shape. Also, instead of the second cross groove 66b, an I-shaped groove capable of engaging with the parallel pin 74 may be formed. In that case, the non-circular outer surface 66c on the outer periphery side of the second cross groove 66b is formed in a substantially I-shape.

[0063] In this embodiment, the first groove portion that engages with the spring pin 47 (first engagement portion) is a cross-shaped first cross groove 66a, making it easier to align the phase of the feed roller shaft 46 with the coupling member 66 during the installation work of the conveying roller unit 40, which will be described later.

[0064] The rib 66d is formed to form the outermost peripheral portion of the coupling member 66. In other words, the rib 66d is formed so that the ridge line of the rib 66d protrudes further toward the outer periphery of the coupling member 66 than the non-circular outer surface 66c. Therefore, when the coupling member 66 is viewed in the axial direction, the outer shape of the coupling member 66 formed by the ridge line of the rib 66d is circular. The outer diameter of the rib 66d relative to the center line of the coupling member 66 is smaller than the outer diameter of the feed roller 44.

[0065] The rib 66d is formed so as to be inclined in the sheet width direction Dw with respect to the sheet conveying direction Df. That is, when viewed from the document conveying path CP side (the same viewpoint as in FIG. 5), the rib 66d extends downstream in the sheet conveying direction Df in a direction inclined away from the center 44C of the feed roller 44 in the sheet width direction Dw (to the right in FIG. 5).

[0066] Here, the center 44C of the feed roller 44 refers to the center position in the sheet width direction Dw of the outer circumferential surface of the feed roller 44 (the surface that comes into contact with the document to be conveyed). In this embodiment, the center 44C of the feed roller 44 in the sheet width direction Dw coincides with the conveyance center that serves as the reference for the position of the document in the sheet width direction Dw. Note that the ADF 102 in this embodiment is a so-called center-based sheet conveying device that is configured to convey the document so that the position of the document in the sheet width direction Dw is aligned with the conveyance center.

[0067] The inclination angle θ of the rib 66d with respect to the sheet conveying direction Df (FIG. 8(a)) is, for example, 10 degrees or more and 50 degrees or less, and preferably 21 degrees or more and 30 degrees or less. In one example of this embodiment, the inclination angle θ is 23 degrees. The inclination angle θ of the rib 66d is the angle between the sheet conveying direction Df and the tangent direction of the ridge line of the rib 66d at the intersection between the ridge line of the rib 66d and the center line of the coupling member 66, when viewed from a direction perpendicular to both the sheet conveying direction Df and the sheet width direction Dw.

[0068] If the inclination angle θ of the rib 66d is small, the pitch of the spirally formed rib 66d narrows, making the outer peripheral surface of the coupling member 66 substantially cylindrical. Therefore, if the inclination angle θ of the rib 66d is small, the ribs 66d are arranged at a short pitch in the axial direction, which may make it difficult to remove the rib 66d from the mold during resin molding. On the other hand, if the inclination angle θ of the rib 66d is too large, the leading edge of the document may get caught on the side of the rib 66d, which may result in poor transport despite the presence of the rib 66d. Furthermore, by setting the inclination angle θ to an appropriate value (e.g., between 21 and 30 degrees), the rib 66d can scoop up any bent corners of the document, as described below.

[0069] In this embodiment, the coupling member 66 is formed with three ribs 66d. By forming multiple ribs 66d parallel to one another in a multi-strand winding configuration, each rib 66d can be appropriately inclined and the spacing between the ribs 66d can be prevented from becoming too large. For example, if the coupling member 66 has only one rib 66d, and attempting to incline the rib 66d appropriately would require a wider pitch (the spacing between adjacent ridges of the rib 66d). In this case, the leading edge of the document may slip between the ridges of the rib 66d and come into contact with the non-circular outer surface 66c, potentially hindering the rib 66d from reducing transport defects. In this embodiment, the use of three ribs 66d allows the rib 66d to be appropriately inclined and the pitch of the rib 66d to be narrower.

[0070] The number of ribs 66d is not limited to three, but may be two or four or more. If a slight increase in the pitch of the ribs 66d is acceptable, the coupling member 66 may have only one rib 66d.

[0071] In this embodiment, each rib 66d is formed in a spiral shape that makes at least one revolution around the center line (rotation axis) of the coupling member 66. In other words, when the coupling member 66 is viewed in the axial direction, the rotation angle of the range in which the rib 66d is provided relative to the center line of the coupling member 66 is 360 degrees or more. By forming the rib 66d to make at least one revolution around the outer periphery of the coupling member 66, it is possible to reduce the possibility that the leading edge of the document will get caught on the edge of the ridge line of the rib 66d.

[0072] The coupling member 66 may be a resin-molded product in which each portion (66a-66e) is integrally formed by a method such as injection molding. For example, the outer surface shape of the coupling member 66 (the noncircular outer surface 66c and the rib 66d) is divided into two parts by a plane passing through the center axis of the coupling member 66, with one of the divided parts being formed by a movable mold and the other being formed by a fixed mold. The inner surface shape of the coupling member 66 (the first cross groove 66a and the second cross groove 66b) is formed by a slide core that slides in the axial direction of the coupling member 66. In this case, since the first cross groove 66a and the second cross groove 66b are both cross-shaped and continuous in the axial direction, the first cross groove 66a and the second cross groove 66b can be formed by a single slide core, and the slide core can be easily demolded. In other words, according to this embodiment, the coupling member 66 can be molded into a desired shape using a general demolding method. The coupling member 66 may also be formed by combining multiple parts.

[0073] (How to attach and detach the transport roller unit) Next, a method for attaching and detaching the transport roller unit 40 will be described with reference to Figures 9 and 10. Figures 9 and 10 are views of the open access cover 315 as seen from the guide surface 315g side.

[0074] When attaching the conveying roller unit 40 to the opening / closing cover 315, the user first engages the end of the feed roller shaft 46 with the coupling member 66, as shown in Fig. 9. Next, as shown in Fig. 10, the user rotates the conveying roller unit 40 around the coupling member 66 as a fulcrum, pushing it into the recess 78. Then, the conveying roller unit 40 is positioned by the bearing support portion 65 and the protrusion 77, and is held by the bearing clamping portion 64 and the separation arm holding portion 76, which serve as holding means, thereby completing the attachment of the conveying roller unit 40.

[0075] A method for attaching the conveying roller unit 40 will now be described in more detail. First, to hold the conveying roller unit 40, the holder member 45 is grasped while pressing the separation arm 55. As an example, the index finger of the right hand grasps a part of the holder member 45 while pressing the separation arm 55 with the thumb. This causes the separation arm 55 to elastically deform in the direction of arrow B.

[0076] In this state, as shown in FIG. 9 , the user inserts the end (spring pin 47) of the feed roller shaft 46 into the coupling member 66. At this time, the user can visually confirm that the spring pin 47 engages with the first cross groove 66a of the coupling member 66. If the rotational phases of the feed roller shaft 46 and the coupling member 66 do not match, causing problems with engagement, the user can align the rotational phase of the feed roller shaft 46 with the coupling member 66 and then engage the spring pin 47 with the coupling member 66. To align the rotational phases, the user may rotate the feed roller shaft 46 or the feed roller 44 with their fingers, or may tilt the entire conveyor roller unit 40. As a result, the spring pin 47 engages with the first cross groove 66a of the coupling member 66, connecting the drive shaft 68 and the feed roller shaft 46 via the coupling member 66.

[0077] 9, the other axial end of the feed roller shaft 46 (the opposite side of the spring pin 47) is separated from the open-close cover 315. The user rotates the conveying roller unit 40 in the direction of arrow C, using the coupling member 66 as a fulcrum, so as to push the conveying roller unit 40 into the recess 78.

[0078] 10, the rotation of the conveying roller unit 40 causes the first bearing portion 46a provided on the other end of the feed roller shaft 46 to engage with the bearing support portion 65 of the opening / closing cover 315. Also, the protrusion portion 77 (FIG. 5) of the opening / closing cover 315 engages with the groove shape of the holder member 45. This positions the conveying roller unit 40 in the sheet conveying direction Df and the sheet width direction Dw.

[0079] Furthermore, in parallel with the above operation, the first bearing portion 46a passes through the entrance of the bearing clamping portion 64 while elastically deforming so as to push the bearing clamping portion 64 apart, and is held inside the bearing clamping portion 64. Furthermore, when the user releases his or her fingers from the spacing arm 55, the spacing arm 55 returns to its original state from the elastically deformed state, and the locked portion 55a of the spacing arm 55 engages with the spacing arm holding portion 76. With the bearing clamping portion 64 clamping the first bearing portion 46a and the spacing arm holding portion 76 engaging the locked portion 55a, the conveyance roller unit 40 is held by the open / close cover 315 in a state where it is restricted from moving in a direction away from the recessed portion 78 (toward the viewer in FIG. 10 ).

[0080] Through the above procedure, the transport roller unit 40 is attached to the opening / closing cover 315.

[0081] To remove the conveyance roller unit 40 from the open-close cover 315, simply perform the above steps in reverse. That is, the user presses the separation arm 55 of the conveyance roller unit 40 attached to the open-close cover 315 to release the locked portion 55a from the separation arm holder 76. In this state, the user rotates the conveyance roller unit 40 around the coupling member 66 as a fulcrum in a direction away from the recess 78 (the opposite direction to the direction of arrow C in FIG. 9 ) to remove the conveyance roller unit 40 from the bearing clamping portion 64, the bearing support portion 65, and the protrusion 77. The user then removes the end (spring pin 47) of the feed roller shaft 46 from the coupling member 66, thereby completing the removal of the conveyance roller unit 40.

[0082] (Summary of this embodiment) If at least a portion of the coupling member 66 is exposed to the document transport path CP, and the rib 66d were not provided, the leading edge of the document may become caught on the non-circular outer surface 66c. In other words, the rotation radius of at least a portion of the non-circular outer surface 66c (particularly the recess 66c2) with respect to the rotation axis of the feed roller shaft 46 is smaller than the outer diameter of the feed roller 44. Therefore, when the feed roller 44 is driven to rotate, the movement speed of at least a portion of the non-circular outer surface 66c is slower than the circumferential speed of the feed roller 44. In other words, the movement speed of at least a portion of the non-circular outer surface 66c is slower than the movement speed of the leading edge of the document transported by the feed roller 44. When the leading edge of the document transported by the feed roller 44 becomes caught on the non-circular outer surface 66c of the coupling member 66 at a position away from the feed roller 44 in the sheet width direction Dw, a force that tends to rotate the document is generated. This force may cause document transport problems such as skew or jamming. Even if the non-circular outer surface 66c has an outer shape other than a substantially cross shape, if the coupling member 66 has an outer shape that is non-circular when viewed in the axial direction, there is a possibility that poor conveyance may occur for the same reason.

[0083] In particular, depending on the size of the document, the corners of the document (corners at the leading and side edges of the document) may pass through the position of the coupling member 66. In this case, when a document is transported with its corners folded (corners folded toward the coupling member 66), the corners are likely to come into contact with the non-circular outer surface 66c, which tends to cause transport problems.

[0084] In contrast, according to this embodiment, the coupling member 66 is provided with a rib 66d on its outer periphery, which extends in a direction inclined outward in the sheet width direction Dw toward the downstream side of the sheet transport direction Df when viewed from the document transport path CP. This rib 66d prevents the leading edge of the document from getting caught on the noncircular outer surface 66c of the coupling member 66. Even if the document has a bent corner, the corner of the document being transported contacts the rib 66d, which protrudes outward from the noncircular outer surface 66c. In this case, the rib 66d, which is inclined outward in the sheet width direction Dw toward the downstream side of the sheet transport direction Df, guides the document so as to push the bent corner outward in the sheet width direction Dw. In other words, the inclination of the rib 66d can scoop up the bent corner of the document. Therefore, the document can pass through the coupling member 66 without the corner of the document coming into contact with the noncircular outer surface 66c.

[0085] Therefore, according to this embodiment, it is possible to provide a sheet conveying device, an image reading device, and an image forming apparatus that can reduce the occurrence of conveyance failures.

[0086] Furthermore, according to this embodiment, the conveyance roller unit 40 is attached to or detached from the open-close cover 315 (support member) when the open-close cover 315 is in the open position. Therefore, when attaching the conveyance roller unit 40, the user can insert the end of the feed roller shaft 46 into the coupling member 66 while visually checking the coupling member 66 exposed from the guide surface 315g. This makes it easy to visually confirm the position where the feed roller shaft 46 should be inserted, improving the workability of the attachment work. Also, the rotational phase of the feed roller shaft 46 can be more easily aligned with the coupling member 66.

[0087] (Other embodiments) In the above-described embodiment, the rib 66d inclined outward in the sheet width direction Dw is formed on the outer periphery of the coupling member 66. Alternatively, for example, the rib 66d may be formed in a ring shape parallel to the sheet conveying direction Df, or the rib 66d may be inclined inward in the sheet width direction Dw. Even in these examples, the outer shape of the coupling member 66 when viewed in the sheet width direction Dw is circular, thereby reducing the possibility that the leading edge of the document will get caught on the non-circular outer surface 66c. However, in these examples, when conveying a document with a folded corner, the corner cannot be scooped up, so it is preferable to use the rib 66d inclined outward in the sheet width direction Dw, as in the above-described embodiment.

[0088] Furthermore, even if the outer periphery of the coupling member 66 is cylindrical, the same advantages as those of the above-described modified example are obtained, but the corners of a folded document cannot be scooped up. Furthermore, if the outer periphery of the coupling member 66 is cylindrical, the thickness of the coupling member 66 will differ significantly between the direction in which the first cross groove 66a and the second cross groove 66b extend and the other directions. Therefore, shrinkage during resin molding may reduce the dimensional accuracy of the inner periphery of the coupling member 66. According to this embodiment, the rib 66d is formed while leaving the non-circular outer surface 66c that conforms to the first cross groove 66a and the second cross groove 66b, thereby preventing a reduction in dimensional accuracy.

[0089] In the above-described embodiment, a configuration has been described in which the coupling member 66 attached to the drive shaft 68 of the open-close cover 315 engages with the end of the feed roller shaft 46 of the transport roller unit 40. Alternatively, a configuration in which the coupling member attached to the feed roller shaft 46 engages with the end of the drive shaft 68 may be used. Even in this case, as long as at least a portion of the coupling member is exposed to the document transport path CP, the same advantages as those of the above-described embodiment can be obtained by providing a rib 66d similar to that of the above-described embodiment. Note that the above-described embodiment has the advantage that the user can engage the end of the feed roller shaft 46 with the coupling member 66 while visually checking the first cross groove 66a on the inside of the coupling member 66.

[0090] In the above-described embodiments, a configuration example in which the present technology is applied to the ADF 102, which is a sheet conveying device that conveys documents in the image reading device 101, has been described. However, the present technology is not limited to this, and may be applied to, for example, a sheet conveying device that conveys sheets used as recording materials in an image forming device. Furthermore, the "roller member" and "roller unit" are not limited to the feed roller 44 disposed downstream of the pickup roller 43, and the conveying roller unit 40 including the pickup roller 43 and the feed roller 44. [Explanation of symbols]

[0091] 40... Roller unit (conveying roller unit) / 44... Roller member (feed roller) / 45... Holder member / 46... Roller shaft (feed roller shaft) / 66... ​​Coupling member / 66d... Rib / 68... Drive shaft / 72... Drive source (feed motor)

Claims

1. a support member provided with a guide surface that forms a sheet conveyance path; a roller unit including a roller member that conveys a sheet through the conveyance path, a roller shaft that supports the roller member, and a holder member that holds the roller member and the roller shaft, the roller unit being detachably attached to the support member; a drive shaft provided on the support member; a coupling member connecting the drive shaft and the roller shaft; a drive source that supplies a driving force to the roller shaft via the drive shaft and the coupling member; Equipped with At least a portion of the coupling member is exposed to the conveying path, When the coupling member is viewed from the conveying path, a rib is provided on the outer periphery of the coupling member, the rib extending in a direction inclined toward downstream in the sheet conveying direction and away from the center of the roller member in the sheet width direction perpendicular to the sheet conveying direction. A sheet conveying device characterized by:

2. Further, a main body unit is provided to support the support member, the support member is movable relative to the main unit between a closed position where the transport path is formed between the guide surface and the main unit and an open position where the transport path is opened, When the support member is in the open position, the roller unit is attached to and detached from the support member.

2. The sheet transport device according to claim 1.

3. The coupling member is attached to the drive shaft.

2. The sheet transport device according to claim 1.

4. a first engaging portion that protrudes outward from an outer circumferential surface of the roller shaft is provided at an end of the roller shaft; the coupling member has a first groove portion formed on an inner peripheral side of the coupling member and engaged with the first engaging portion, and a non-circular outer surface formed on an outer peripheral side of the coupling member, the non-circular outer surface includes a plurality of ridges that are provided on extensions of the first grooves as viewed in the seat width direction and extend in the seat width direction, and a recess that is provided between the plurality of ridges and is recessed toward the center of the coupling member compared to the plurality of ridges, The rib protrudes toward the outer periphery of the coupling member beyond the non-circular outer surface.

4. The sheet transport device according to claim 3.

5. The first groove portion is formed in a cross shape when viewed in the seat width direction.

5. The sheet transport device according to claim 4.

6. the first engagement portion is a pin fitted in a hole formed in the roller shaft; 5. The sheet transport device according to claim 4.

7. the support member has a holding means for holding the roller unit, the holding means being provided at a position different from the coupling member in the sheet width direction, the roller unit is held by the holding means by being rotated around the coupling member as a fulcrum after the first engagement portion is engaged with the first groove portion; 5. The sheet transport device according to claim 4.

8. the roller unit has an operating portion that is elastically deformed when operated by a user, the holding means includes a locking portion configured to lock a portion of the operation portion and to release the portion of the operation portion when the operation portion is elastically deformed.

8. The sheet transport device according to claim 7.

9. The roller unit has a bearing portion that rotatably supports the roller shaft, the holding means includes a bearing clamping portion that clamps the bearing portion, 8. The sheet transport device according to claim 7.

10. A second engagement portion is provided at an end of the drive shaft and protrudes outward from the outer circumferential surface of the drive shaft, the coupling member has a second groove portion formed on an inner peripheral side of the coupling member and engaged with the second engaging portion, and a non-circular outer surface formed on an outer peripheral side of the coupling member, the non-circular outer surface includes a plurality of ridges that are provided on extensions of the second grooves as viewed in the seat width direction and extend in the seat width direction, and a recess that is provided between the plurality of ridges and is recessed toward the center of the coupling member compared to the plurality of ridges, The rib protrudes toward the outer periphery of the coupling member beyond the non-circular outer surface.

4. The sheet transport device according to claim 3.

11. The second groove portion is formed in a cross shape when viewed in the seat width direction.

11. The sheet transport device according to claim 10.

12. The second engagement portion is a pin fitted into a hole formed in the drive shaft.

11. The sheet transport device according to claim 10.

13. The rib is formed in a spiral shape that makes at least one revolution around the rotation axis of the coupling member.

2. The sheet transport device according to claim 1.

14. an outer diameter of the rib relative to the center of the coupling member is smaller than an outer diameter of the roller member; 2. The sheet transport device according to claim 1.

15. A plurality of ribs including the rib are formed parallel to each other on the outer periphery of the coupling member.

2. The sheet transport device according to claim 1.

16. an inclination angle of the rib with respect to the sheet conveying direction is equal to or greater than 10 degrees and equal to or less than 50 degrees; 2. The sheet transport device according to claim 1.

17. a placement section on which a sheet is placed; a separating member that comes into contact with the roller member to form a nip portion and applies frictional force to the sheets fed from the stacking unit at the nip portion to separate the sheets; Further comprising:

2. The sheet transport device according to claim 1.

18. a sheet conveying device according to any one of claims 1 to 17; a reading unit for reading an image on a sheet conveyed by the sheet conveying device; An image reading device comprising:

19. The image reading device according to claim 18; an image forming means for forming an image on a recording material based on image information acquired by the image reading device; An image forming apparatus comprising:

Images