SHEET FEEDING DEVICE AND IMAGE FORMING APPARATUS

Abstract

To solve the problem in which, when a foreign substance enters a drive connection part where a gear tooth surface of a feed roller and a conveyance roller, and an idler gear are provided, there is the risk that the gear tooth surface is likely to wear off and that noise occurs in an engagement part of the gears.SOLUTION: A paper feed unit 430 having idler gears 412, 413, 414 for transmitting a rotation driving force of a feed roller 403 to a pick roller 402 has a support member 406 for supporting the idler gears 412, 413, 414. Also, a paper feed unit 430 includes a cover part 406a for covering at least part of the idler gears 412, 413, 414 between a sheet S to be conveyed and the idler gears 412, 413, 414, when viewed from a rotation axis direction of the feed roller 403.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a sheet feeding device for feeding a sheet, and an image forming apparatus including the sheet feeding device.

Background Art

[0002] Conventionally, as an image forming apparatus such as an electrophotographic system, a configuration is widely known in which a sheet feeding device for feeding a sheet accommodated in a paper feed tray toward an image forming unit is provided, and an image is formed on the sheet fed by the sheet feeding device. Such a sheet feeding device includes a feeding roller for feeding a sheet accommodated in a paper feed cassette, and a conveying roller for conveying the sheet fed by the feeding roller toward the image forming unit.

[0003] Patent Document 1 discloses a configuration in which gear tooth surfaces are provided at the outer peripheral ends of a feeding roller and a conveying roller, and rotational drive is transmitted from the conveying roller to the feeding roller via an idler gear that engages with both gear tooth surfaces.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in Patent Document 1, if foreign substances such as dust and paper powder enter the gear tooth surfaces of the feeding roller and the conveying roller, and the drive connection part where the idler gear is provided, the following problems may occur. That is, due to the entry of foreign substances, the gear tooth surfaces are likely to wear, and abnormal noise may occur at the meshing part of the gears.

[0006] Therefore, an object of the present invention is to suppress the entry of foreign matter into the drive connection portion in a configuration in which the driving of a feed roller and a conveyance roller is connected.

Means for Solving the Problems

[0007] The present invention includes a rotatable first conveyance means for feeding a sheet loaded on the loading portion, a rotatable second conveyance means for conveying the sheet fed by the first conveyance means, and a drive connection portion for transmitting the rotational force of the second conveyance means to the first conveyance means. The drive connection portion is provided coaxially with the rotation axis of the first conveyance means, and includes a first gear for rotating the first conveyance means, a second gear provided coaxially with the rotation axis of the second conveyance means for rotating the second conveyance means, and a transmission gear portion for transmitting the rotational force of the first gear to the second gear and including at least one idler gear. The feeding means includes a support member for supporting the drive connection portion, and a cover portion disposed between the sheet conveyed by the first conveyance means or the second conveyance means and the drive connection portion when viewed in the rotational axis direction of the second conveyance means, and covering a part of the first gear and a part of the second gear so as to be exposed toward the loading portion. The sheet conveyance device is characterized by having the cover portion. Two rotation force of the first gear to the second gear One rotation force of the first gear to the second gear Ni when viewed in the rotational axis direction of the second conveyance means, and a cover portion disposed between the sheet conveyed by the first conveyance means or the second conveyance means and the drive connection portion, and covering a part of the first gear and a part of the second gear so as to be exposed toward the loading portion. The gear meshing portion of the drive connection portion and the transmission gear portion covering a part of the first gear and a part of the second gear so as to be exposed toward the loading portion.

Advantages of the Invention

[0008] According to the present invention, in a configuration in which the driving of a feed roller and a conveyance roller is connected, it is possible to suppress the entry of foreign matter into the drive connection portion.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0010] Hereinafter, with reference to the drawings, preferred embodiments of the present invention will be exemplarily described in detail. In the following embodiments, an example in which a laser beam printer as an image forming apparatus including the sheet feeding device of the present invention is used will be described. However, the components described in this embodiment are merely examples, and unless otherwise specifically described, they are not intended to limit the scope of the present invention. For example, the image forming apparatus may be a copying machine, a multifunction machine, or a facsimile apparatus. Further, the image forming method does not necessarily have to be an electrophotographic method, and other image forming methods such as an electrostatic recording method or an inkjet method may be used.

[0011] (Example 1) <Configuration of the Image Forming Apparatus> FIG. 1 is a schematic cross-sectional view of an image forming apparatus 100 including the sheet conveying device of this embodiment. As shown in FIG. 1, the image forming apparatus 100 in this embodiment forms an image by an electrophotographic recording method and has a sheet feeding unit 400 as a sheet conveying device.

[0012] The paper feeding unit 400 is provided rotatably with respect to the apparatus main body of the image forming apparatus 100. As shown in FIG. 1, the paper feeding unit 400 includes a paper feeding tray 401 as a sheet stacking unit, and a regulating member 417 that regulates an end portion in the width direction of the sheet S orthogonal to the sheet conveying direction. The paper feeding unit 400 also includes a pick-up roller 402 as a first conveying means, a feed roller 403 as a second conveying means, and a separation roller 421 as a separation means facing the feed roller 403. The pick-up roller 402 feeds the sheet S stacked on the paper feeding tray 401 toward a separation portion Ns formed by the opposing feed roller 402 and separation roller 421. The sheet S fed by the pick-up roller 402 is separated one by one at the separation portion Ns by the feed roller 403 and the separation roller 421, and then conveyed toward a transfer portion described later.

[0013] In this embodiment, the image forming units SY, SM, SC, and SK respectively form toner images corresponding to the colors of yellow, magenta, cyan, and black, and each have a photosensitive drum 111, 112, 113, 114 as an image carrier, and charging means and developing means (not shown). When an image forming operation is started by a control means (not shown) such as a controller receiving an image signal, the photosensitive drums 111 to 114 are rotationally driven. During the rotation process, the photosensitive drums 111 to 114 are uniformly charged by charging means (not shown), and exposed by an exposure means 120 according to the image signal. As a result, electrostatic latent images corresponding to each color are formed on the surfaces of the photosensitive drums 111 to 114, and then developed by developing means (not shown), so that toner images of each color are formed on the surfaces of the photosensitive drums 111 to 114.

[0014] The toner images formed on the photoreceptor drums 111 to 114 are sequentially superimposed and primarily transferred onto the intermediate transfer belt 130 as an intermediate transfer member. After that, as the intermediate transfer belt 130 moves, it reaches the transfer section N2 where the secondary transfer roller 122 contacts the intermediate transfer belt 130. Then, the toner images formed on the surfaces of the photoreceptor drums 111 to 114 are transferred onto the sheet S fed by the sheet feeding section 400 at the transfer section N2, and then are fixed on the sheet S by being heated and pressurized by the rotatable heating member 107 and the pressurizing member 108. After that, the sheet S on which the image is formed is discharged from the image forming apparatus 100 by the discharge rollers 109 and 110 and stacked on the discharge tray 104.

[0015] <Sheet feeding operation by the sheet feeding section> FIG. 2(a) is a schematic cross-sectional view for explaining the configuration of the sheet feeding section 400 in a state where the pick roller 402 is not in contact with the sheet S, and FIG. 2(b) is a schematic cross-sectional view for explaining the configuration of the sheet feeding section 400 in a state where the pick roller 402 is in contact with the sheet S. As shown in FIGS. 2(a) to 2(b), the sheet feeding section 400 of the present embodiment can move in the directions of the illustrated arrows R1 and R2 to contact or separate from the sheet S stacked on the sheet feeding tray 401.

[0016] As shown in FIG. 2(a), the pick roller 402 is supported by a support member 406 that can swing in the directions of the illustrated arrow R1 and the illustrated arrow R2 with the rotation axis of the feed roller 403 as the rotation center. In the non-sheet feeding state where the sheet S is not fed to the transfer section N2, the support member 406 rotates in the direction of the illustrated arrow R2 to form the state of FIG. 2(a), so that the pick roller 402 is in a state of not contacting the sheet S.

[0017] As shown in FIG. 2(b), when feeding the sheet S stacked on the sheet feeding tray 401 to the transfer section N2, the controller (not shown) controls the support member 406 to rotate in the direction of the illustrated arrow R1. Thereby, the pick roller 402 comes into contact with the uppermost surface 416 of the sheet material S stacked on the sheet feeding tray 401, and the sheet S can be fed.

[0018] Then, when the sheet feeding operation of the sheet S starts, the pick roller 402 is driven to rotate in the clockwise direction in FIG. 2(a), and the sheet S is fed toward the separation unit Ns. The sheet S fed toward the separation unit Ns is guided to the separation unit Ns by the nip guide 420, and then is separated one by one by the feed roller 403 rotating in the clockwise direction and the separation roller 421 in the separation unit Ns, and is conveyed to the conveying roller pair 310.

[0019] At this time, when only one sheet S is fed toward the separation unit Ns by the pick roller 402, the separation roller 421 is driven to rotate passively by receiving the rotational force from the feed roller 403 through the sheet S. A torque limiter is provided on the separation roller 421, and it is configured to rotate only when receiving a predetermined rotational torque. On the other hand, when two or more sheet materials S are fed toward the separation unit Ns by the pick roller 402, the rotational force of the feed roller 403 is not transmitted to the separation roller 421 due to the frictional force generated between the plurality of sheets S that have reached the separation unit Ns. Then, the separation roller 421 does not rotate due to the torque limiter, and the sheet S in contact with the separation roller 421 stays in the separation unit Ns due to the frictional force with the separation roller 421, and only the sheet S in contact with the feed roller 403 is conveyed to the conveying roller pair 310. In the configuration of this embodiment, the separation of the sheet S is performed using such a mechanism.

[0020] In this embodiment, the separation roller 421 is configured to have a torque limiter, but it is not limited to this. For example, the separation roller 421 may be configured to rotate in the same direction as the feed roller 403, and when a plurality of sheets S are fed to the separation unit Ns, only the sheet in contact with the separation roller 421 may be conveyed toward the paper feed tray 401 by the rotation of the separation roller 421. In this case, similar to the configuration of this embodiment, it is necessary to use a separation roller 421 such that the frictional force generated between the separation roller 421 and the sheet S in contact therewith is greater than the frictional force generated between the plurality of sheets S.

[0021] When the sheet feeding operation of the sheet S toward the separation unit Ns by the pick roller 402 is completed, the support member 406 rotates in the direction of the arrow R2 in the figure, so that the pick roller 402 is separated from the surface of the sheet S until the next sheet feeding operation is performed, and the state shown in Fig. 2(a) is obtained. Thus, in this embodiment, when performing the sheet feeding operation of the sheet S, instead of the sheet feeding tray 401 moving up and down toward the pick roller 402, the pick roller 402 is moved up and down with respect to the sheet S stacked on the sheet feeding tray 401 by rotating the support member 406.

[0022] <Configuration of the sheet feeding unit> Fig. 3(a) is a schematic perspective view for explaining the configuration of the sheet feeding unit 400 arranged in the image forming apparatus 100, and Fig. 3(b) is a schematic cross-sectional view taken along the cutting line AA in Fig. 3(a), which is a schematic cross-sectional view for explaining the peripheral configuration of the sheet feeding unit 430. Further, Fig. 4(a) is a schematic diagram for explaining the configuration of the sheet feeding unit 430 detachably arranged in the image forming apparatus 100, and Fig. 4(b) is a schematic diagram when the sheet feeding unit 430 is viewed from an angle different from that in Fig. 4(a).

[0023] As shown in Fig. 1 and Figs. 3(a) to 3(b), the sheet feeding unit 400 in this embodiment is provided so as to be rotatable with respect to the side surface of the image forming apparatus 100, and the sheet feeding tray 401 is a manual sheet feeding tray. As shown in Fig. 1 and Fig. 2(a), the sheet feeding unit 400 further includes an opening / closing unit 30 that supports the sheet feeding tray 401 and constitutes the housing on the side surface of the image forming apparatus 100, a rotation shaft 31, and a support tray 32 for supporting the sheet S stacked on the sheet feeding tray 401. The support tray 32 has a configuration that expands and contracts in the sheet conveyance direction, and when a sheet S longer in the sheet conveyance direction than the opening / closing unit 30 is stacked, the end of the sheet S can be supported by pulling it out to the upstream side in the sheet conveyance direction.

[0024] The opening / closing part 30 forms a state of opening or closing the paper feeding part 400 with respect to the image forming apparatus 100 by rotating in the directions of the illustrated arrows R3 and R4 about the rotation axis 31 as the rotation center. From the state of Fig. 3(a), with respect to the sheet conveyance direction, the support tray 32 is in a folded state, that is, a state of being stored so as to be shorter than the length of the opening / closing part 30, and by rotating the opening / closing part 30 in the direction of the illustrated arrow R4, the side surface of the image forming apparatus 100 is closed. At this time, the opening / closing part 30 becomes a part constituting the housing of the image forming apparatus 100. On the other hand, when conveying the sheet S from the paper feed tray 401 to the transfer part N2, the opening / closing part 30 is rotated in the direction of the illustrated arrow R3 to the state of Fig. 3(a), the sheet S is loaded on the paper feed tray 401, and the paper feed unit 430 (feeding means) including the pick roller 402 is operated. Also, in this state, it becomes possible for the user or the service person to access the paper feed unit 430, and the user or the service person can perform the attaching / detaching operation of the paper feed unit 430.

[0025] Next, with reference to Figs. 4(a) to 4(b), the configuration of the paper feed unit 430 for conveying the sheet S will be described. As shown in Fig. 4(a), the feed roller 403 is provided on the feed roller core 405 as a support, and a gear 405a (first gear) for rotating the feed roller 403 is provided coaxially with the rotation axis of the feed roller core 405. The feed roller 403 is rotationally driven by being transmitted a driving force from a drive source (not shown) of the apparatus main body of the image forming apparatus 100 via the drive shaft 410.

[0026] The pick roller 402 is provided on the pick roller core 404 as a support, and a gear 404a (second gear) for rotating the pick roller 402 is provided coaxially with the rotation axis of the pick roller core 404. The pick roller core 404 is supported in a rotatable state by the support member 406 and the paper feed cover 407. The pick roller 402 is rotationally driven when a driving force is transmitted from the gear 405a to the gear 404a via an idler gear, which will be described later, when the feed roller 403 is rotationally driven.

[0027] In FIGS. 4(a) to 4(b), since the idler gear is covered by the cover portion 406a provided on the support member 406, the idler gear cannot be visually recognized. Hereinafter, the configuration of the paper feed unit 430 including the configuration of the idler gear will be described in detail with reference to FIGS. 5(a) to 5(b). FIG. 5(a) is a schematic perspective view showing a state where the paper feed cover 407 is removed from the paper feed unit 430. Further, FIG. 5(b) is a schematic perspective view showing a state where the paper feed unit 430 is disassembled into the pick roller unit 431, the feed roller unit 432, and the paper feed cover 407, respectively.

[0028] As shown in FIG. 5(a), in the present embodiment, three idler gears 412, 413, and 414 (third gear) as drive coupling portions are rotatably provided on the support member 406 in order to transmit the rotational driving force from the gear 405a to the gear 404a.

[0029] As shown in FIG. 5(b), the feed roller unit 432 includes a drive coupling 411, a drive shaft 410, a feed roller core 405, and a feed roller 403. The drive coupling 411 is provided at one end portion in the rotational axis direction of the drive shaft 410, and the feed roller core 405 is provided at the other end portion in the rotational axis direction of the drive shaft 410. When a driving force is transmitted from a drive source (not shown) provided in the apparatus main body of the image forming apparatus 100 to the drive coupling 411, the drive coupling 411, the drive shaft 410, and the feed roller core 405 rotate integrally, so that the feed roller 403 rotates.

[0030] The pick roller unit 431 is composed of a cam 409 (drive receiving part), a support shaft 408, a support member 406, idler gears 412, 413, 414, a pick roller core 404, and a pick roller 402. In the axial direction of the rotation axis of the pick roller 402, a cam 409 is provided at one end of the support shaft 408, and a support member 406 is provided at the other end. Also, in this embodiment, the support shaft 408 is formed in a cylindrical shape with a hollow structure, and when the paper feeding unit 430 is assembled, the drive shaft 410 is arranged inside the support shaft 408 in the radial direction of the cylinder. Such a configuration of the support shaft 408 and the drive shaft 410 is hereinafter referred to as a double pipe configuration, which will be described in detail later.

[0031] Depending on whether there is transmission of the driving force from a driving source (not shown) provided in the apparatus main body of the image forming apparatus 100 to the cam 409, the cam 409, the support shaft 408, and the support member 406 swing integrally in the direction of the illustrated arrow R1 or the illustrated arrow R2 in FIG. 5(b). As a result, the switching between the contact state and the separated state of the pick roller 402 with respect to the sheet S, which was described in FIGS. 2(a) to (b), is performed. Here, the drive transmission mechanism for rotationally driving the drive coupling 411 and the drive transmission mechanism for driving the cam 409 are provided separately. That is, the operations of rotationally driving the feed roller 403 and the pick roller 402 and the operation of swinging the pick roller 402 can be controlled to have different driving transmission timings.

[0032] FIG. 6 is a schematic diagram for explaining the configuration of the support member 406. As shown in FIG. 6, the support member 406 has shaft portions 406b, 406c, 406d, 406e, 406f having a cylindrical shape. The support shaft 408 is attached to the shaft portion 406b, and the shaft portion 406c rotatably supports the pick roller core 404. Also, the shaft portions 406d, 406e, 406f rotatably support the three idler gears 412, 413, 414.

[0033] As shown in FIG. 6, the support member 406 of this embodiment further has a cover portion 406a, and the cover portion 406a is provided to extend in the sheet conveyance direction. As shown in FIGS. 2(a) to 2(b), the cover portion 406a is provided between the sheet conveyed by the paper feeding unit 430 and the idler gears 412, 413, and 414 as drive connection portions when viewed from the direction of the rotation axis of the feed roller 403. Further, as shown in FIG. 4(b), the cover portion 406a is configured to cover at least a part of the drive connection portion that transmits the driving force from the gear 405a to the gear 404a. In this embodiment, the drive connection portion has the gear 404a, the gear 405a, and the idler gears 412, 413, and 414, and the cover portion 406a is provided to cover the positions where the idler gears 412, 413, and 414 of the drive connection portion are arranged.

[0034] Here, in FIG. 2(b), let the A portion be the gear meshing portion between the gear 404a and the idler gear 414, and the B portion be the gear meshing portion between the idler gears 412 and 413. As shown in FIG. 2(b), when the pick roller 402 and the feed roller 403 rotate clockwise during paper feeding, the gear meshing portions such as the A portion and the B portion rotate in the entrainment direction that entrains foreign matter into the inside of the paper feeding unit 430. More specifically, the entrainment direction refers to the direction from the cover portion 406a toward the paper feeding cover 407 when viewed from the direction of the rotation axis of the feed roller 403 shown in FIG. 2(b).

[0035] During the sheet feeding operation of the sheet S by the paper feeding unit 430, if foreign matter enters the gear meshing portion as described above, the gear tooth surfaces may be easily worn, or abnormal noise may occur in the gear meshing portion. In this embodiment, by providing the cover portion 406a that covers at least a part of the drive connection portion that transmits the rotational force of the feed roller 403 to the pick roller 402, it is possible to suppress the entry of foreign matter into the drive connection portion of the paper feeding unit 430.

[0036] Also, by providing the cover portion 406a, it is possible to suppress the entry of foreign matter into the drive connection portion not only during the paper feeding operation but also, for example, when a service technician or user removes the paper feeding unit 430 from the image forming apparatus 100 as shown in FIG. 4(b). When the paper feeding unit 430 is attached and detached by a service technician or user, or while the paper feeding unit 430 is placed on a workbench, foreign matter may enter the gear meshing portion. Even in such a case, the cover portion 406a covers the drive connection portion, thereby suppressing the entry of foreign matter.

[0037] In addition, in this embodiment, a configuration in which three idler gears are provided between the gear 405a and the gear 404a has been described. However, the number of idler gears is not limited to three. Any number of idler gears may be used as long as the rotational driving force from the feed roller 403 can be transmitted to the pick roller 402.

[0038] Further, in this embodiment, the cover portion 406a is configured to cover the position where the gear meshing portion rotates in the winding direction. However, not all gear meshing portions of the paper feeding unit 430 need to be covered. As long as at least one gear meshing portion that rotates in the winding direction is covered, the effects of the configuration of this embodiment can be obtained.

[0039] In this embodiment, the cover portion 406a is provided integrally with the support member 406. According to this configuration, it is possible to reduce the number of parts and achieve cost reduction. However, the configuration of providing the cover portion 406a is not limited to this. The cover portion may be provided by a member formed separately from the support member 406. In that case, the cover portion may be configured to cover at least a part of the drive connection portion. Thus, it may be provided on the support member 406 or the paper feed cover 407, or on any other member as long as it does not affect the operation of the paper feeding unit 430.

[0040] Also, in this embodiment, although gears were used as the driving means for transmitting the rotation of the feed roller 403 to the pick roller 402, the present invention is not limited to this, and a configuration in which drive is transmitted by rotating members such as pulleys and belts may also be used. Further, in this embodiment, the separation method using the separation roller provided with a torque limiter has been described, but the method for separating the sheet S is not limited to this, and a separation pad method or the like may be appropriately adopted.

[0041] In this embodiment, the configuration of the paper feed unit 430 that conveys the sheet S from the manual paper feed tray 401 in the paper feed unit 400 provided on the side surface of the image forming apparatus 100 has been described. Thus, in the configuration of conveying the sheet S from the rotatable manual paper feed tray 401, since the paper feed tray 401 is exposed outside the image forming apparatus 100 during image formation, foreign matters such as paper dust are likely to be mixed into the paper feed unit 430, and the effects of this embodiment can be more easily obtained. However, the present invention is not limited to this, and a drawer-type paper feed tray that is detachable from the image forming apparatus 100 and is a paper feed unit provided inside the image forming apparatus 100 can also adopt the configuration of this embodiment, and the same effects as this embodiment can be obtained.

[0042] [Double pipe configuration] Next, with reference to FIGS. 4(a) to (b), FIGS. 5(a) to (b), and FIG. 7, the double pipe configuration of the drive shaft 410 and the support shaft 408 in the paper feed unit 430 of this embodiment will be described. FIG. 7 is a schematic diagram for explaining a paper feed unit 530 as a comparative example of this embodiment. Note that, except that the configuration of the paper feed unit 530 is different from that of the paper feed unit 430 in this embodiment, other configurations such as the image forming apparatus are substantially the same as those in this embodiment. Therefore, in the following description of the comparative example, the same reference numerals are given to the same configurations and operations as those in this embodiment, and the description thereof is omitted.

[0043] The paper feeding unit 530 of the comparative example includes a feed roller 503, a pick-up roller 502, and a support member 550, and has a configuration in which the pick-up roller 502 rotates when the rotational drive of the feed roller 403 is transmitted. The support member 550 rotatably supports a pick-up roller core 552, idler gears 554, 555, 556, and a feed roller core 553. A drive gear 557 is provided at the end of a drive shaft 510 for rotationally driving the feed roller 503, and the drive shaft 510 is rotatably positioned with respect to the drive unit of the apparatus main body of the image forming apparatus, so that it cannot be detached from the apparatus main body of the image forming apparatus. Therefore, in the configuration of the comparative example, the support member 550 also cannot be detached from the apparatus main body of the image forming apparatus.

[0044] The pick-up roller core 552 as a support for the pick-up roller 502 and the feed roller core 553 as a support for the feed roller 503 are positioned by a retaining member 551 so that movement in the rotational axis direction of the feed roller 503 is restricted. Further, the idler gear 556 is positioned so that movement in the rotational axis direction of the feed roller 503 is restricted by the pick-up roller core 552. Similarly, the idler gear 554 is positioned so that movement in the rotational axis direction of the feed roller 503 is restricted by the feed roller core 553.

[0045] The movement of the idler gear 555 in the rotational axis direction of the feed roller 503 is restricted by the idler gear 556. Therefore, in the configuration of the comparative example, when exchanging the pick-up roller 502 and the feed roller 503, after removing the retaining member 551 from the support member 550, it is necessary to remove the pick-up roller core 552 and the feed roller core 553 from the support member 550 and exchange them. At this time, since the idler gears 554, 555, 556 are not restricted in position by the pick-up roller core 552 and the feed roller core 553, they can be removed.

[0046] When attaching the pick roller core 552 and the feed roller core 553 to the paper feed unit 530, first attach the idler gears 554, 555, and 556 to the shaft portion (not shown) of the support member 550. Then, align the phases of the gears so that the gear 552a provided at the end of the pick roller core 552 and the gear 553a provided at the end of the feed roller core 553 mesh with the idler gears 554 and 556, respectively.

[0047] At the end of the support member 550 of the comparative example, a cam member 550a that is driven by receiving force from a drive unit (not shown) of the apparatus main body of the image forming apparatus is provided. The cam member 550a has the same function as the cam 409 of the present embodiment, and it is possible to swing the support member 550 by transmitting a driving force from a drive source (not shown) provided in the apparatus main body of the image forming apparatus to the cam member 550a.

[0048] As shown in FIG. 7, in the configuration of the comparative example, in order to swing the support member 550 and bring the pick roller 502 into contact with the sheet S, it is necessary to secure the space C indicated by the dotted line. On the other hand, in the present embodiment, as shown in FIGS. 4(a) to 4(b), by forming the support shaft 408 in a hollow cylindrical shape and providing the drive shaft 410 inside the cylinder of the support shaft 408, there is no member disposed in the space C in the comparative example, and it is not necessary to secure the space C. In the present embodiment, the pick roller 402, the feed roller 403, and the three idler gears are integrally configured by the double pipe configuration of the support shaft 408 and the drive shaft 410.

[0049] In the configuration of the comparative example, as shown in FIG. 7, since it was necessary to secure the space C, there were restrictions on the arrangement and size of the regulating member 417 (shown in FIG. 3(a)) that regulates the end portion of the sheet S loaded on the paper feed tray 401 in the sheet width direction. Specifically, since it was necessary to secure the space C, it was difficult to dispose the regulating member 417 on the downstream side of the pick roller 502 in the sheet conveyance direction.

[0050] On the other hand, in this embodiment, since it is not necessary to provide the space C by the double pipe configuration, the regulating member 417 can be arranged downstream of the pick roller 402 in the sheet conveyance direction, and the degree of freedom in designing the device configuration can be improved. Further, by providing the regulating member 417 downstream of the pick roller 402 in the sheet conveyance direction, the skew of the sheet S when the sheet S is conveyed by the pick roller 402 and the feed roller 403 can be more effectively suppressed by the regulating member 417.

[0051] Further, according to the configuration of this embodiment, the cam 409 and the drive coupling 411 have a detachable configuration with respect to a drive unit (not shown) of the rough concave body of the image forming apparatus 100 in the rotational axis direction of the feed roller 403. That is, the paper feed unit 430 can be attached to and detached from the image forming apparatus 100 by moving it in the rotational axis direction of the feed roller 403.

[0052] By configuring the paper feed unit 430 to be detachable in this way, the pick roller 402 and the feed roller 403 can be replaced simultaneously. Further, since the paper feed unit 430 is configured so that the idler gears do not come off individually, the paper feed unit 430 can be replaced without worrying about the meshing between the gears 404a, 405a and the idler gears, and the workability of the user or the service person can be improved.

[0053] Further, in the configuration of the comparative example, when replacing the pick roller 502 and the feed roller 503 from the image forming apparatus, the user or the service person had to work with their hands interfering with the image forming apparatus. On the other hand, in this embodiment, after removing the paper feed unit 430 from the image forming apparatus 100, it is possible to remove and replace the pick roller 402 and the feed roller 403 from the paper feed unit 430 in a wide space, and the workability can be improved compared to the comparative example.

[0054] Furthermore, in the configuration of the comparative example, the cam member 550a for swinging the support member 550 is disposed upstream of the feed roller 503 with respect to the sheet conveyance direction. Therefore, it is necessary to provide a space for disposing a drive source (not shown) for transmitting a driving force to the cam member 550a upstream of the feed roller 503 with respect to the sheet conveyance direction, and it is necessary to enlarge the apparatus main body of the image forming apparatus upstream in the sheet conveyance direction. On the other hand, according to the double pipe configuration of the present embodiment, since the cam 409 is disposed in the vicinity of the support shaft 408 that encloses the drive shaft 410, the drive source for driving the cam 409 can be disposed in the vicinity of the position where the feed roller 403 is provided with respect to the sheet conveyance direction. Thereby, it is not necessary to provide the drive source for driving the cam 409 upstream of the feed roller 403 with respect to the sheet conveyance direction, and an increase in the size of the apparatus main body of the image forming apparatus 100 can be suppressed.

[0055] In the above description, the details of the double pipe configuration have been described. However, even in the sheet feeding unit 530 of the comparative example that does not have the double pipe configuration, it is possible to adopt the configuration of the cover portion described in the present embodiment. That is, in order to obtain the effect of suppressing the entry of foreign matter into the drive connection portion of the sheet feeding unit 430 described in the present embodiment, the double pipe configuration is not an essential configuration. However, by adopting the double pipe configuration, it is possible to obtain the above-described effects in addition to the effect of suppressing the entry of foreign matter.

Explanation of Reference Numerals

[0056] 401 Sheet Feeding Tray 402 Pickup Roller 403 Feed Roller 406 Support Member 406a Cover Portion 412 Idler Gear 413 Idler Gear 414 Idler Gear 420 Nip Guide

Claims

1. A loading section for loading sheets; a feeding means having a rotatable first conveying means for feeding a sheet stacked on the stacking section, a rotatable second conveying means for conveying the sheet fed by the first conveying means, and a drive connecting portion for transmitting a rotational force of the second conveying means to the first conveying means, the drive coupling portion includes a first gear provided coaxially with a rotation axis of the first conveying means for rotating the first conveying means, a second gear provided coaxially with a rotation axis of the second conveying means for rotating the second conveying means, and a transmission gear portion for transmitting a rotational force of the second gear to the first gear, the transmission gear portion including at least one idler gear; The sheet conveying device is characterized in that the feeding means has a support member that supports the drive connection portion, and a cover portion that is arranged between the sheet conveyed by the first conveying means or the second conveying means and the drive connection portion when viewed in the direction of the rotation axis of the second conveying means, and that covers the gear meshing portion of the drive connection portion and the transmission gear portion so that a portion of the first gear and a portion of the second gear are exposed toward the loading portion.

2. 2. The sheet transport means according to claim 1, wherein a diameter of a tip of said at least one idler gear is smaller than a diameter of a tip of said first gear and a diameter of a tip of said second gear.

3. 3. The sheet conveying device according to claim 2, wherein the at least one idler gear includes a plurality of idler gears that mesh with each other, the gear meshing portion includes a portion where the plurality of idler gears mesh with each other, and the cover portion covers the portion where the plurality of idler gears mesh with each other and the plurality of idler gears.

4. 4. The sheet transport device according to claim 1, wherein the first transport means is rotatable about the second transport means as a rotation center so as to come into contact with or move away from the sheets stacked on the stacking section.

5. a separating means facing the first conveying means, The sheet conveying device according to claim 4, characterized in that the second conveying means rotates in contact with the sheet stacked in the stacking section by receiving a rotational force transmitted from the first conveying means, thereby feeding the sheet to a separation section formed by the first conveying means and the separation means.

6. a drive shaft that is provided coaxially with a rotation axis of the first conveying means and transmits a drive force to the first conveying means; a support shaft that supports the support member and rotates the second conveying means; and a drive receiving section that rotates the support shaft to rotate the support member and bring the second conveying means into contact with or away from the sheets loaded on the stacking section, 6. The sheet transport device according to claim 4, wherein the support shaft has a hollow cylindrical shape, and the drive shaft is disposed inside the cylindrical support shaft.

7. a transfer section for transferring a toner image carried on the image carrier onto a sheet; An image forming apparatus comprising: the sheet conveying device according to claim 1 .

8. an opening / closing unit that constitutes a part of a housing of the image forming apparatus; and a rotation shaft for rotating the opening / closing unit, The loading section is provided on the opening / closing section, 8. The image forming apparatus according to claim 7, wherein the feeding means is disposed at a position that allows a user to access the feeding means when the opening / closing section is rotated about the rotation axis to open the loading section.

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