Sheet conveying device and image forming apparatus

Abstract

To provide a sheet conveyance device capable of exchanging a conveyance roller without exchanging a bearing member.SOLUTION: A sheet conveyance device includes a conveyance roller having one end part and the other end part in the direction of a rotary shaft, an open bearing that supports one end part of the conveyance roller, a frame supporting the open bearing, and the other end support part that supports the other end part of the conveyance roller. The open bearing has a conveyance roller support part that supports the conveyance roller, and an opening that allows the conveyance roller to be removed from the conveyance roller support part in the direction perpendicular to the rotary shaft. The open bearing is movable between a first position that regulates the conveyance roller from moving in the direction of the rotary shaft and a second position that allows the conveyance roller to move in the direction of the rotary shaft. In such a state that the open bearing is positioned at the second position, the other end part can be removed from the other end support part by moving the conveyance roller from the other end part toward the one end part.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a sheet conveying device that conveys a sheet and an image forming apparatus that uses the sheet conveying device. [Background technology]

[0002] 2. Description of the Related Art In conventional image forming apparatuses such as printers, copiers, and facsimiles, sheets are conveyed by conveying rollers provided in a sheet conveying device.

[0003] In recent years, the extended lifespan of image forming devices has led to increased demand for easier maintenance of internal parts. In particular, the transport rollers gradually wear out as they grip and transport sheets, requiring periodic replacement.

[0004] Patent Document 1 describes a configuration in which a roller member having a rotating shaft and a bearing member fixed to the rotating shaft is replaceable. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 4988245 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the configuration of Patent Document 1, when replacing the roller member, it is necessary to replace the bearing member as well.

[0007] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a sheet transporting device in which the transport roller can be replaced without replacing the bearing member. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, the present invention provides a sheet conveying device comprising: a conveying roller that rotates around a rotation axis, has one end and another end in the direction of the rotation axis, and conveys a sheet; an open bearing that supports the one end so that the conveying roller can rotate; a frame that supports the open bearing; and an other end support part that supports the other end so that the conveying roller can rotate, wherein the open bearing has a conveying roller support part that supports the conveying roller, and an open part that allows the conveying roller to be removed from the conveying roller support part in a direction perpendicular to the rotation axis, and the open bearing, when attached to the frame, is movable between a first position that restricts the conveying roller from moving in the direction of the rotation axis, and a second position where the conveying roller is removed from the open bearing, and the open bearing supports the one end so that the conveying roller can rotate. Receiver When in the second position, the conveying roller is allowed to move in the direction of the rotation axis, and when the open bearing is moved from the first position to the second position, the conveying roller passes through the open portion, and with the open bearing positioned at the second position, the conveying roller can be moved from the other end toward the one end, thereby making it possible to remove the other end from the other end support portion. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a sheet transporting device in which the transport roller can be replaced without replacing the bearing member. [Brief explanation of the drawings]

[0010] [Figure 1] Schematic diagram of an image forming apparatus according to the first embodiment [Figure 2] FIG. 1 is a perspective view showing the arrangement of a sheet conveying device according to the first embodiment; [Figure 3] 1 is a bottom view showing the arrangement of a sheet conveying device in the first embodiment from the vertical direction. [Figure 4] FIG. 10 is a perspective view showing the arrangement of the sheet conveying device when the bearing portion is configured by a bearing member different from the frame in the first embodiment; [Figure 5]FIG. 1 is a diagram showing the configuration of an open bearing in the first embodiment. [Figure 6] FIG. 10 is a diagram showing the configuration of a bearing receiving portion of a frame in the first embodiment. [Figure 7] FIG. 10 is a diagram showing the relationship between the bearing receiving portion of the frame and the open bearing in the first embodiment. [Figure 8] 1 is a cross-sectional view showing an engagement portion between an open bearing and a shaft member and an engagement portion between a bearing portion and a shaft member in the first embodiment. [Figure 9] 10 is a cross-sectional view showing a method for restricting movement of a conveying roller when a second restricting portion is located on the bearing portion side in the first embodiment. [Figure 10] FIG. 10 is a diagram showing a method of transmitting drive between a drive transmission member and a conveying roller in the first embodiment. [Figure 11] FIG. 10 is a diagram showing a method for removing the conveying roller from the frame in the first embodiment. [Figure 12] FIG. 10 is a perspective view showing the arrangement of a sheet conveying device according to the second embodiment. [Figure 13] FIG. 10 is a diagram showing the configuration of a bearing receiving portion of a frame in the second embodiment. [Figure 14] FIG. 10 is a diagram showing a method for removing the conveying roller from the frame in the second embodiment. [Figure 15] FIG. 10 is a diagram showing the shape of a drive transmission member passing hole in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Example 1 As an example of the configuration of an image forming apparatus having a sheet transport device according to the present invention, an embodiment in which the image forming apparatus is applied to an electrophotographic laser printer will be specifically described. In this description, the overall configuration of the image forming apparatus according to the present invention will be described first, and then the configuration of the sheet transport device of the image forming apparatus according to the present invention will be described.

[0012] However, unless otherwise specified, the dimensions, materials, shapes, relative positions, etc. of the components described in this embodiment are not intended to limit the scope of the present invention to those. Furthermore, the image forming apparatus according to the present invention is not limited to laser printers, but may be applied to other image forming apparatuses such as copiers and facsimiles.

[0013] <Image forming device> FIG. 1 is a cross-sectional view showing the configuration of an electrophotographic laser printer having a double-sided image forming function as an example of an image forming apparatus according to an embodiment of the present invention.

[0014] The image forming apparatus 101 shown in FIG. 1 is roughly composed of a sheet feeding unit, an image forming unit that forms an image on a sheet, a fixing unit, a paper discharge / reversing unit, and a duplex conveying unit.

[0015] The image forming apparatus 101 includes a process cartridge 1 that is detachably attached to the main body of the apparatus. The process cartridge 1 is made up of a photosensitive drum 2 and process means such as a developing unit and a charging roller (not shown).

[0016] A scanner unit 3 is disposed vertically above the process cartridge 1, and exposes the photosensitive drum 2 to light based on an image signal. After the photosensitive drum 2 is charged to a predetermined negative potential by a charging roller (not shown), an electrostatic latent image is formed on it by the scanner unit 3. This electrostatic latent image is reverse-developed by a developing unit (not shown) inside the process cartridge 1, and negative toner is attached to form a toner image.

[0017] The sheet feeding unit has a paper feed roller 4 attached to the image forming apparatus 101 and a paper feed cassette 5 that stores sheets S such as paper. The paper feed cassette 5 is detachable from the image forming apparatus main body 101. The sheets S stored in the paper feed cassette 5 are separated and fed one by one from the paper feed cassette 5 by the paper feed roller 4 that is rotated by the power of a paper feed drive unit (not shown). The fed sheet S is transported to a registration roller pair 7 by a paper feed transport roller pair 6, where skew correction is performed, and the sheet S is transported to the transfer unit.

[0018] In the transfer section, a bias voltage of positive polarity is applied by a bias applying means (not shown) to the transfer roller 8. As a result, the toner image is transferred as an unfixed image onto the sheet S conveyed to the transfer section.

[0019] The sheet S onto which the toner image has been transferred is transported to a fixing device 9 provided downstream in the transport direction of the transfer unit. The fixing device 9 fixes the toner image transferred onto the sheet S, and has a heating roller 10 as a fixing member and a pressure roller 11 as a pressure member. The heating roller 10 is heated by a heater, which is a heating means (not shown). The pressure roller 11 rotates while being pressed against the heating roller 10. The sheet S is nipped and transported in the fixing nip formed by the heating roller 10 and the pressure roller 11, and the toner image is fixed to the surface of the sheet S by applying heat and pressure to the sheet S.

[0020] The sheet S with the fixed toner image is transported from the fixing device 9 to a paper discharge reversal section. The paper discharge reversal section has a paper discharge roller 13, a paper discharge roller 14, a reversal roller 15, and a double-sided flapper 12. In the case of single-sided printing, in which an image is formed on one side of the sheet S, the double-sided flapper 12 waits at the position indicated by the solid line and guides the sheet S to the paper discharge nip formed by the paper discharge roller 13 and the paper discharge roller 14. The sheet S is then discharged onto the paper discharge tray 16 by the paper discharge roller 13 and the paper discharge roller 14.

[0021] In the case of double-sided printing, in which images are formed on both sides of sheet S, double-sided flapper 12 waits at the position indicated by the dotted line and guides sheet S toward the reversal nip formed by discharge roller 13 and reversal roller 15. Then, sheet S is transported toward the reversal nip by fixing device 9. Discharge roller 13 is rotated in the reverse direction by a rotation direction switching means (not shown) when the trailing edge of sheet S reaches a predetermined position. As a result, sheet S passes through conveying roller pair 17 and re-feed roller pair 18 with the trailing edge at the front, and is re-sent in an inverted state relative to registration roller pair 7.

[0022] Thereafter, as with single-sided printing, the sheet S is corrected for skew by a pair of registration rollers 7, and a toner image is transferred to the second side of the sheet S by a transfer roller 8, and fixed by a fixing device 9. The sheet S is then discharged onto a discharge tray 16 by a discharge roller 13 and a discharge roller 14, completing double-sided printing.

[0023] <Sheet conveying device> In the image forming apparatus 101, a portion involved in conveying the sheet S can be called a sheet conveying apparatus 100. The sheet conveying apparatus 100 according to the present invention will be described with reference to FIGS.

[0024] 2 and 3 are diagrams showing a sheet conveying device 100 in which a conveying roller 20 and a driven roller 21 constituting a conveying roller pair 17 are assembled to a frame 40. FIG. 2 is a perspective view showing the arrangement of the sheet conveying device 100 in this embodiment 1. FIG. 3 is a bottom view showing the arrangement of the sheet conveying device 100 in this embodiment 1 from the vertical direction. FIG. 3 is a view of the sheet conveying device 100 as seen from below in the vertical direction, along arrow A in FIG. 2. FIG. 4 is a perspective view showing the arrangement of the sheet conveying device 100 in this embodiment 1 when the bearing portion 30 is formed by a bearing member 30a different from that of the frame 40.

[0025] The sheet conveying device 100 includes a conveying roller pair 17 including a conveying roller 20, a frame 40, an open bearing 31, and a bearing portion 30.

[0026] 2 and 3, the conveying roller 20 rotates around a rotation axis, has a roller member 20a and a shaft member 20b, and has one end and the other end in the direction of the rotation axis. The driven roller 21, together with the conveying roller 20, sandwiches and conveys the sheet S. The driven roller 21 is urged in the direction E toward the conveying roller 20 by an urging member 22, which is a compression spring, via a spring bearing member 23. The conveying roller 20 is urged in the direction E via the driven roller 21.

[0027] To enable the conveying roller 20 to rotate, one end of the shaft member 20b (one end of the conveying roller 20) is supported by an open bearing 31, and the other end of the shaft member 20b (the other end of the conveying roller 20) is supported by a bearing portion 30 serving as the other end support portion.

[0028] In this embodiment, the bearing portion 30 is provided on the frame 40 to reduce the number of components. More specifically, the frame 40 is a metal plate, and the bearing portion 30 is formed integrally with the frame 40. However, the bearing portion 30 may be configured using a member separate from the frame 40, such as a bearing member 30a that supports the entire circumference of the end of the shaft member 20b as shown in FIG. 4 or an open bearing 31, which will be described later. In this case, by using a material with high slidability for the separate member that constitutes the bearing portion, it is possible to improve the slidability of the conveyance roller 20.

[0029] Next, the method of engaging the open bearing 31 with the frame 40 will be described with reference to FIGS. 5 to 8. FIG. 8 is an enlarged view of the engagement portion between the open bearing 31 and the shaft member 20b and the engagement portion between the bearing portion 30 and the shaft member 20b in the cross-sectional view of the CC portion in FIG. 3. FIG. 5 is a view showing the configuration of the open bearing 31 that supports the conveying roller 20. FIG. 5(a) is a view of the open bearing 31 as seen from the center of the sheet width in the direction of the rotation axis, and FIG. 5(b) is a view of FIG. 5(a) as seen from direction D. Also, arrow E in FIG. 5(a) indicates the biasing direction of the biasing force applied to the conveying roller 20 by the driven roller 21.

[0030] The open bearing 31 has a semicircular conveying roller support portion 31a that supports the conveying roller 20 that receives a biasing force in the E direction, and an open portion 31b that is open on the side opposite to the biasing force in the E direction that the conveying roller 20 receives. When one end of the conveying roller 20 passes through the open portion 31b, the one end of the conveying roller 20 can be removed from the conveying roller support portion 31a in a direction perpendicular to the rotation axis of the conveying roller 20. The open bearing 31 also has a portion 31c to be prevented from rotating relative to the frame 40, and a restricting portion 31j that restricts movement of the conveying roller 20 in the rotation axis direction at a first position described below.

[0031] 6 is a view of the bearing receiving portion 41 of the frame 40 supporting the open bearing 31, as viewed from the H direction, which is the direction from the open bearing 31 to the bearing portion 30 in FIG.

[0032] The bearing receiving portion 41 in FIG. 6 has a bearing support portion (first portion) 41a that supports the open bearing 31 so that the open bearing 31 is positioned at a first position, which will be described later. The bearing receiving portion 41 further has a frame cutout portion 41b (guide portion, second portion) that guides the open bearing 31 from the first position to a second position, which will be described later, and a rotation preventing portion 41c that engages with the rotation-prevented portion 31c of the open bearing 31. The bearing support portion 41a and the frame cutout portion 41b are holes (first holes) formed in the frame 40. The rotation preventing portion 41c is a hole (second hole) formed in the frame 40. The bearing support portion 41a and the frame cutout portion 41b are connected to each other. The bearing support portion 41a and the rotation preventing portion 41c are located at positions spaced apart from the bearing support portion 41a and the frame cutout portion 41b.

[0033] Figure 7 is a diagram showing three states of the open bearing 31 relative to the bearing support portion 41, and is a cross-sectional view of part II in Figure 8. Figure 7(a) is a diagram showing the open bearing 31 in a first position. Figure 7(b) is a diagram showing the open bearing 31 in a third position. Figure 7(c) is a diagram showing the open bearing 31 in a second position.

[0034] 7(a), when the open bearing 31 is in the first position, the open bearing 31 supports the transport roller 20 so that the transport roller 20 can rotate, and movement of the transport roller 20 in the direction of the rotation axis is restricted. When the open bearing 31 is in the first position, the anti-rotation portion 31c of the open bearing 31 engages with the anti-rotation portion 41c of the frame 40 to restrict rotation of the open bearing 31. In addition, movement of the open bearing 31 from the first position to the second position is restricted.

[0035] When the engagement between the stopped rotation portion 31c and the rotation preventing portion 41c is released, the open bearing 31 is allowed to move from the first position to the third position. In this embodiment, the open bearing 31 rotates counterclockwise in Figure 7(b) to move from the first position to the third position. As shown in Figure 7(b), when the open bearing 31 is in the third position, the engagement between the stopped rotation portion 31c and the rotation preventing portion 41c is released, and the open bearing 31 is allowed to move toward the second position.

[0036] 7(c), when the open bearing 31 is in the second position, the open bearing 31 is detached from the conveying roller 20, and the conveying roller 20 is allowed to move in the direction of the rotation axis. In this embodiment, the second position is a position where the open bearing 31 is moved from the third position (FIG. 7(b)) in the X direction, which is the direction toward the frame cutout portion 41b.

[0037] The open bearing 31 has an arm 31k as an operating portion. The arm 31k extends in a direction intersecting (preferably perpendicular to) the direction of the rotation axis of the conveyance roller 20, and has a rotation-stopped portion 31c. The arm 31k is located between the bearing receiving portion 41 of the frame 40 and the bearing portion 30 in the direction of the rotation axis of the conveyance roller 20, and is exposed toward the space between the bearing receiving portion 41 and the bearing portion 30. The space between the bearing receiving portion 41 and the bearing portion 30 is a conveyance path through which the sheet S conveyed by the conveyance roller 20 passes.

[0038] An operator replacing the conveying roller 20 can access the conveying path (work space) from outside the image forming apparatus 101 (outside the sheet conveying device 100). Because the arm 31k is exposed to the conveying path, an operator replacing the conveying roller 20 can easily access the conveying path, operate the arm 31k, and move the open bearing 31. Note that the image forming apparatus 101 or the sheet conveying device 100 may have an opening / closing member that covers an opening through which the operator can access the conveying path.

[0039] The open bearing 31 restricts movement in the direction F, which is the rotation axis direction, relative to the frame 40 by sandwiching the frame 40 between the three frame locking ribs 31g, 31h, and 31i and the frame locking surface 31e. The open bearing 31 has a notch passing portion (width L6) that is narrower than the width L7 of the frame cutout portion 41b in a direction perpendicular to the movement direction from the third position to the second position. This allows the open bearing 31 and the shaft member 20b to move along the frame cutout portion 41b to the second position without interference.

[0040] Next, the restriction of the rotational axis direction of the conveying roller 20 will be described with reference to Figures 8 and 9. In the state shown in Figure 8, the width L1 of the open portion 31b shown in Figure 5(a) is equal to or greater than the shaft diameter L2 of the shaft member 20b shown in Figure 8. Therefore, the open bearing 31 can move from the first position to the second position so that the conveying roller 20 passes through the open portion 31b.

[0041] The shaft member 20b has a first regulated portion 20c with an outer diameter L3 and a second regulated portion 20d with an outer diameter L4, where L3 > L2 and L4 > L2 are satisfied with respect to the shaft diameter L2 of the shaft member 20b. The first regulated portion 20c is located between the bearing portion engaging portion 20f, which serves as the other end of the shaft, and the open bearing 31 in the direction of the rotation axis. Therefore, when the open bearing 31 is in the first position and the conveying roller 20 is supported by the open bearing 31, the two regulated portions 20c and 20d can come into contact with the regulating portion 31j of the open bearing 31. In this contact state, movement of the conveying roller 20 in the direction F, which is the direction of the rotation axis, is restricted. When the open bearing 31 moves from the first position to the second position, the two regulated portions 20c and 20d and the regulating portion 31j separate, allowing the conveying roller 20 to move in the direction of the rotation axis.

[0042] In this embodiment, the relationship between the width L1 of the open portion 31b and the shaft diameter L2 of the shaft member 20b is L1≧L2, but as shown in Figure 5(c), the open portion 31b may have a protrusion 31f where the width of a part of the open portion 31b is L2>L1a, and the open bearing 31 may be configured to bend and attached to the conveying roller 20. Using this configuration makes it less likely that the open bearing 31 will fall off when the conveying roller 20 is assembled to the frame 40.

[0043] In this embodiment, the open bearing 31 is sandwiched between the first regulated portion 20c and the second regulated portion 20d of the conveying roller 20 to regulate movement in the direction F, which is the rotation axis direction. Because the two regulated portions 20c and 20d are located close to each other with the open bearing 31 in between, the positional accuracy of the conveying roller 20 in the rotation axis direction can be increased.

[0044] 9(a), the second regulated portion 20d may be brought into contact with a bearing portion 30 provided on a frame 40 to regulate movement of the conveying roller 20 in the H direction. The H direction is parallel to the width direction of the sheet S, and can be said to be the direction from the open bearing 31 toward the center of the sheet S. The H direction is parallel to the direction of the rotation axis of the conveying roller 20.

[0045] 9(b), the end of the shaft member of the conveying roller 20 on the bearing unit 30 side may be abutted against a separate member to restrict movement of the conveying roller 20 in the H direction. In this example, an abutment surface 30b provided in the bearing unit 30 provided in the frame 40 is used as the separate member against which the end of the conveying roller 20 abuts. By abutting the conveying roller 20 against the bearing unit 30 or the separate member, it becomes possible to easily recognize the position of the conveying roller 20 in the rotation axis direction when attaching the conveying roller 20 to the frame 40, thereby improving the efficiency of work when replacing the conveying roller.

[0046] Furthermore, the distance L8 between two of the frame locking ribs 31g, 31h and the remaining rib 31i is smaller than the distance L9 between the outer diameter portion of the second regulated portion 20d (or the first regulated portion 20c) and the end of the frame cutout portion 41b. Therefore, when the open bearing 31 is in the second position, the conveying roller 20 is allowed to move in the F direction, which is the rotational axis direction of the open bearing 31. Also, the open bearing 31 can be configured to be detachable from the frame 40 by moving the open bearing 31 in the H direction when it is in the second position.

[0047] Figure 10 is a diagram showing a method of transmitting drive from a drive transmission member 50, which is a gear, to a conveying roller 20. Figure 10(a) is a cross-sectional view of part CC in Figure 3. Figure 10(b) is an enlarged view of the region from the open bearing 31 to the drive transmission member 50 in the cross-sectional view of Figure 10(a).

[0048] The sheet conveying device 100 has a drive transmission unit 50 for transmitting a driving force from a driving source (not shown). The conveying roller 20 has a drive-received unit 20e for receiving the driving force from the driving source from the drive transmission unit 50. The drive transmission member 50 is supported by a drive transmission member holder 51 provided on the frame 40, and the drive transmission member holder 51 restricts movement of the drive transmission member 50 in the direction F, which is the rotation axis direction.

[0049] FIG. 10(c) is a view of the drive transmission member 50 and the drive-received portion 20e as viewed in the H direction.

[0050] The drive transmission member 50 has a drive transmission part 50a which is an I-shaped hole that transmits driving force to the driven transmission part 20e which is an I-shaped shaft, and the drive transmission part 50a is a through hole in the F direction which is the rotation axis direction.

[0051] 10(c), a gap is provided between the drive transmitted portion 20e and the drive transmitting portion 50a. When the drive transmitting member 50 receives a driving force from a drive source (not shown), the wall surface of the drive transmitting portion 50a abuts against the corners J1, J4 or J2, J3 of the drive transmitted portion 20e, thereby transmitting the driving force to the conveyance roller 20. Furthermore, by providing a gap between the drive transmitted portion 20e and the drive transmitting portion 50a, the conveyance roller 20 can be easily attached to the drive transmitting member 50.

[0052] <Removing the transport roller> A method for removing the transport roller 20 from the frame 40 will be described with reference to FIG.

[0053] FIG. 11 is a cross-sectional view taken along the line CC in FIG. 3, showing a method for removing the transport roller 20 from the frame 40. In FIG.

[0054] Fig. 11(a) is a diagram showing a state in which the open bearing 31 has been moved from the state shown in Fig. 10(a) to the second position, and then the conveying roller 20 has been moved in the direction of the rotation axis from the bearing portion 30 toward the bearing support portion 41. Fig. 11(b) is a diagram showing that the conveying roller 20 has been curved by applying a force in the direction E to the right end of the conveying roller 20 in the figure from the state shown in Fig. 11(a). Fig. 11(c) is a diagram showing the conveying roller 20 in the state shown in Fig. 11(b) having been moved to the right in the figure.

[0055] When the open bearing 31 is in the second position, the bearing engagement portion 20f as the other end of the conveying path roller 20 is detachable from the bearing portion 30 as the other end support portion. With the open bearing 31 in the second position, by moving the conveying roller 20 to the left side in the figure as shown in Fig. 11(a), the bearing portion engagement portion 20f is detached from the bearing portion 30. As a result, the conveying roller 20 can be removed from the frame 40. With respect to the outer diameter L3 of the first regulated portion 20c and the outer diameter L4 of the second regulated portion 20d shown in Fig. 8, the outer diameter L5 of the bearing support portion 41a shown in Fig. 6 satisfies the relationship L3 < L5 and L4 < L5. Thereby, the conveying roller 20 can move in the G direction, which is the direction from the bearing portion 30 to the bearing receiving portion 41 (the direction from the other end to the one end of the conveying roller 20) in the rotational axis direction without contacting the frame 40.

[0056] Also, when moving the conveying roller 20 in the G direction, the driven transmission portion 20e can move in the G direction within the driving transmission portion 50a, which is a through hole, with respect to the driving transmission member 50. Therefore, only the conveying roller 20 can be moved in the G direction with the driving transmission member 50 supported by the driving transmission member holder 51. At this time, the distance L10 between the driving transmission member 50 and the second regulated portion 20d shown in Fig. 10(a) is longer than the moving distance L11 until the engagement between the bearing portion engagement portion 20f and the bearing portion 30 is released. Therefore, when removing the conveying roller 20, the conveying roller 20 can be moved until the engagement between the bearing portion engagement portion 20f and the bearing portion 30 is released.

[0057] 11(b), the conveying roller 20 is tilted in the direction E, which is the biasing direction of the biasing force received from the driven roller 21. Then, as shown in FIG. 11(c), the end of the driven transmission part 20e is moved until it reaches an area to the right of the bearing receiver 41, thereby making it possible to remove only the conveying roller 20 from the frame 40. During this removal, the driven roller 21 remains attached to the frame 40, and the conveying roller 20 is removed in a direction away from the driven roller 21. Because the conveying roller 20 can be removed from the frame 40 without removing the driven roller 21 from the frame 40, the efficiency of the replacement work for the conveying roller 20 can be improved, and maintenance can be enhanced.

[0058] In this embodiment, when removing the transport roller 20 from the frame 40, the transport roller 20 can be removed by bending the transport roller 20. The material of the shaft member 20b of the transport roller 20 preferably contains resin. In this embodiment, the material of the shaft member 20b is resin. The material of the shaft member 20b may also contain resin and metal.

[0059] Furthermore, the transport roller 20 can be attached to the frame 40 by performing the series of removal operations shown in FIGS. 11(a) to 11(c) in reverse order.

[0060] Additionally, the shaft member 20b has a third regulated portion 20g on the bearing portion 30 side. When the conveying roller 20 is supported on the frame 40 by the open bearing 31 and the bearing portion 30, a gap exists between the third regulated portion 20g and the bearing portion 30. The size of this gap is set to be equal to or greater than 0 in the direction F, which is the rotation axis direction, even when taking into account the dimensional tolerances and thermal expansion of the third regulated portion 20g and surrounding parts.

[0061] 11(a) is moved in the H direction, the third regulated portion 20g comes into contact with the bearing portion 30, thereby regulating the movement of the conveying roller 20 in the H direction. At this time, the bearing receiving portion 41 of the frame 40 and the two regulated portions 20c and 20d are located close to each other, making it easy to attach the open bearing 31 to the conveying roller 20.

[0062] The configuration of the present invention allows the conveying roller 20 to be removed by moving the open bearing 31 to the second position when replacing the conveying roller 20, thereby improving the efficiency of the work of replacing the conveying roller 20. Furthermore, since only the conveying roller 20 can be replaced without replacing the open bearing 31, it is possible to minimize the number of replacement parts, which also leads to a reduction in replacement costs.

[0063] Example 2 Next, a second embodiment of the present invention will be described with reference to Figures 12 to 15. In this embodiment, the description of the parts common to the first embodiment will be omitted. The differences from the first embodiment are that the drive transmission member 50 is supported by the transport roller 20 rather than the drive transmission member holder 51, and that the drive transmission member 50 is attached and detached together with the transport roller 20 when the transport roller 20 is attached and detached.

[0064] Fig. 12 is a perspective view of the sheet conveying device 100 in the embodiment 2. Fig. 13 is a view of the bearing receiving portion 42 of the frame 40 as viewed from the open bearing 31 in the H direction, which is the sheet width center direction.

[0065] Figure 13 is a view of the bearing receiver 42 of the frame 40 that supports the open bearing 31 in Example 2, as viewed from direction H, which is the direction from the open bearing 31 to the bearing portion 30 in Figure 8. The bearing receiver 42 in Figure 13 has a bearing support portion (first portion) 42a that supports the open bearing 31 so that the open bearing 31 is positioned at a first position. Furthermore, the bearing receiver 42 has a frame cutout portion 42b (second portion, frame through-hole, guide portion) that guides the open bearing 31 from the first position to a second position, and a rotation preventing portion 42c that engages with the rotation-stopped portion 31c of the open bearing 31.

[0066] The width L12 of the frame cutout portion 42b is a hole that is larger than the shaft diameter L2 of the shaft member 20b. Furthermore, when the open bearing 31 is moved from the second position toward the frame cutout portion 42b, it can be moved to a removal position where it can be removed from the frame 40.

[0067] Fig. 14 is a perspective view of the sheet conveying device 100, showing a method for removing the conveying roller 20. The drive transmission member 50 is supported by the drive-received portion 20e of the conveying roller 20. Fig. 14(a) shows a state in which the open bearing 31 has been removed from the frame 40, and the conveying roller 20 has been moved in the direction G, which is the direction of the open bearing 31, from the center of the sheet width, to release the engagement between the bearing portion 30 and the bearing portion engaging portion 20f.

[0068] 14(b) is a diagram showing the conveying roller 20 removed from the frame 40. As shown in FIG. 14(b), the drive transmission member 50 and the conveying roller 20 can be removed from the frame 40 by moving the conveying roller 20 in the state shown in FIG. 14(a) in the L direction along the frame cutout portion 42b of the frame 40.

[0069] In addition to the frame cutout 42b that allows the conveying roller 20 to pass through, the frame 40 is provided with a drive transmission member passing hole 42d, as shown in Fig. 15, whose width is larger than the outer diameter of the drive transmission member 50. This drive transmission member passing hole 42d prevents the frame 40 and the drive transmission member 50 from coming into contact with each other when the conveying roller 20 is removed.

[0070] The configuration of the second embodiment is such that the transport roller 20 can be attached and detached even on a metal shaft or a highly rigid shaft, on which it is difficult to attach and detach the transport roller 20 at an angle. [Explanation of symbols]

[0071] 2 Photosensitive drum 20 Conveyor roller 20a Roller member 20b Shaft member 20c First restricted part 20d Second restricted part 20e Driven transmission part 20f Bearing engagement part 20g Third Restricted Part 21 driven roller 22 biasing member 30 Bearing section 30a Bearing member 31 Open bearing 31a Conveyor roller support part 31b Open part 31j Regulatory Department 40 frames 41 Bearing holder 41a Bearing support part 41b Frame cutout 42 Bearing holder 42a Bearing support part 42b Frame cutout 50 Drive transmission member 50a Drive transmission part 51 Drive transmission member holder 100 sheet transport device 101 Image forming device

Claims

1. A sheet conveying device, a conveying roller that rotates around a rotation axis, has one end and the other end in the direction of the rotation axis, and conveys a sheet; an open bearing that supports the one end of the conveying roller so that the conveying roller can rotate; a frame supporting the open bearing; an other end support portion that supports the other end portion of the conveying roller so that the conveying roller can rotate; Equipped with the open bearing has a conveying roller support portion that supports the conveying roller, and an open portion that allows the conveying roller to be removed from the conveying roller support portion in a direction perpendicular to the rotation axis, the open bearing, when attached to the frame, is movable between a first position at which the open bearing restricts movement of the transport roller in the direction of the rotation shaft and a second position at which the transport roller is detached from the open bearing, and when the open bearing is in the second position, the transport roller is allowed to move in the direction of the rotation shaft; When the open bearing is moved from the first position to the second position, the conveying roller passes through the open portion, With the open bearing positioned at the second position, the other end can be removed from the other end support portion by moving the conveying roller from the other end toward the one end. A sheet conveying device characterized by:

2. 2. The sheet conveying device according to claim 1, wherein the frame has a bearing support portion that supports the open bearing so that the open bearing is positioned at the first position, and a guide portion that guides the open bearing from the first position to the second position.

3. The open bearing has a rotation-stopped portion, the frame has a rotation preventing portion that engages with the rotation-stopped portion, the engagement between the rotation-stopped portion and the rotation-stopping portion restricts rotation of the open bearing positioned at the first position, the engagement between the rotation-stopped portion and the rotation-stopping portion is released, allowing the open bearing positioned at the first position to rotate from the first position to a third position, 3. The sheet transporting device according to claim 1, wherein the open bearing is movable from the third position to the second position.

4. 4. The sheet transporting device according to claim 3, wherein the open bearing rotates around the rotation axis of the transport roller from the first position to the third position.

5. the open bearing has a restricting portion for restricting movement of the conveying roller in the direction of the rotation shaft at the first position, the conveying roller has a regulated portion that is regulated in movement toward the rotation axis by contacting the regulating portion, When the open bearing is positioned at the first position, the regulated portion and the regulating portion can come into contact with each other, 5. The sheet conveying device according to claim 1, wherein the regulated portion and the regulating portion are separated from each other when the open bearing is positioned at the second position.

6. 6. The sheet conveying device according to claim 1, wherein the frame includes the other end support portion.

7. The sheet conveying device according to claim 5 , wherein the regulated portion is located between the other end and the open bearing in the direction of the rotation shaft when the open bearing is in the first position.

8. 8. The sheet conveying device according to claim 1, further comprising a drive transmission section for transmitting a driving force from a drive source, and the conveying roller has a drive transmission section for receiving the driving force from the drive transmission section.

9. the open bearing is movable from the second position to a removed position where it is removed from the frame; 9. The sheet transport device according to claim 1, wherein the frame includes a removal portion that allows the open bearing to move from the second position to the removal position.

10. 10. The sheet conveying device according to claim 1, wherein the movement direction of the open bearing when it moves to the second position includes a direction perpendicular to the rotation axis of the conveying roller.

11. The sheet conveying device according to any one of claims 1 to 10, a transfer unit that transfers the toner image formed on the photosensitive drum onto a sheet; a fixing unit that fixes the toner transferred to the sheet by the transfer unit; An image forming apparatus comprising:

Images