JP7679181B2 - SHEET FEEDING DEVICE AND IMAGE FORMING APPARATUS - Google Patents

Description

The present invention relates to a sheet feeding device that feeds sheets, and an image forming apparatus equipped with the sheet feeding device.

Conventionally, electrophotographic and other image forming apparatuses are widely known to have a sheet feeding device that feeds sheets stored in a paper feed tray toward an image forming unit, and an image is formed on the sheets fed by the sheet feeding device. Some such sheet feeding devices include a feed roller that feeds sheets stored in a paper feed cassette, and a transport roller that transports the sheets fed by the feed roller toward the image forming unit.

Patent document 1 discloses a configuration in which gear teeth are provided on the outer peripheral ends of the feed roller and the transport roller, and rotational drive is transmitted from the transport roller to the feed roller via an idler gear that engages with both gear teeth.

JP 2005-75479 A

However, in Patent Document 1, if foreign matter such as dust or paper powder gets into the gear tooth surfaces of the feed roller or transport roller, or into the drive connection where the idler gear is provided, the following problems may occur. That is, the inclusion of foreign matter may cause the gear tooth surfaces to wear easily, or may cause abnormal noise at the gear meshing portion.

The present invention aims to prevent foreign matter from entering the drive connection portion in a configuration that connects the drive of the feed roller and the transport roller.

The present invention provides a sheet conveying device including 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 coupling portion for transmitting a rotational force of the second conveying means to the first conveying means, the drive coupling portion including 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 drive coupling portion for transmitting the rotational force of the second gear to the first gear. and a transmission gear portion for transmitting the drive force, the transmission gear portion including at least one idler gear, and the feeding means is characterized in that it has a support member that supports the drive connection portion, and a cover portion that is arranged between the sheet transported by the first transport means or the second transport means and the drive connection portion when viewed in the direction of the rotation axis of the second transport means, and 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.

According to the present invention, in a configuration in which the drive of the feed roller and the transport roller are connected, it is possible to prevent foreign matter from entering the drive connection portion.

FIG. 1 is a schematic cross-sectional view illustrating a configuration of an image forming apparatus according to a first embodiment. FIG. 4 is a schematic cross-sectional view illustrating the operation of the paper feed unit according to the first embodiment. FIG. 4 is a schematic perspective view illustrating a configuration of a paper feed unit according to the first embodiment; FIG. 1 is a schematic diagram illustrating a configuration of a paper feed unit according to a first embodiment of the present invention; FIG. 2 is a schematic exploded view for explaining the configuration of a paper feed unit according to the first embodiment; FIG. 4 is a schematic perspective view illustrating a configuration of a support member according to the first embodiment; FIG. 5 is a schematic perspective view illustrating a configuration of a paper feed unit of a comparative example.

Below, a preferred embodiment of the present invention will be described in detail with reference to the drawings. In the following embodiment, an example will be described in which a laser beam printer is used as an image forming apparatus equipped with a sheet feeding device of the present invention. However, the components described in this embodiment are merely examples, and are not intended to limit the scope of the present invention unless otherwise specified. For example, the image forming apparatus may be a copying machine, a multifunction machine, or a facsimile machine. In addition, the image forming method does not have to be an electrophotographic method, and may be another image forming method such as an electrostatic recording method or an inkjet method.

Example 1
<Configuration of Image Forming Apparatus>
Fig. 1 is a schematic cross-sectional view of an image forming apparatus 100 including a sheet conveying device of the present embodiment. As shown in Fig. 1, the image forming apparatus 100 in this embodiment forms an image by an electrophotographic recording method, and includes a paper feed unit 400 as a sheet conveying device.

The paper feed unit 400 is rotatably provided with respect to the main body of the image forming apparatus 100, and as shown in FIG. 1, has a paper feed tray 401 as a sheet stacking unit, and a regulating member 417 that regulates the end of the sheet S in the width direction perpendicular to the sheet conveying direction. The paper feed unit 400 also has a pick 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 roller 402 feeds the sheets S loaded on the paper feed tray 401 toward a separation section Ns formed by the feed roller 402 and the separation roller 421 facing each other. The sheets S fed by the pick roller 402 are separated one by one at the separation section Ns by the feed roller 403 and the separation roller 421, and then conveyed toward a transfer section to be described later.

In this embodiment, the image forming units SY, SM, SC, and SK form toner images corresponding to the colors yellow, magenta, cyan, and black, respectively, and each has photoconductor drums 111, 112, 113, and 114 as image carriers, and charging means and developing means (not shown). When a control means (not shown) such as a controller receives an image signal to start the image forming operation, the photoconductor drums 111 to 114 are rotated. During the rotation process, the photoconductor drums 111 to 114 are uniformly charged by a 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 photoconductor drums 111 to 114, and then developed by a developing means (not shown) to form toner images of each color on the surfaces of the photoconductor drums 111 to 114.

The toner images formed on the photoconductor drums 111-114 are sequentially superimposed and primarily transferred onto the intermediate transfer belt 130 as an intermediate transfer body, and then reach the transfer section N2 where the secondary transfer roller 122 and the intermediate transfer belt 130 come into contact as the intermediate transfer belt 130 moves. The toner images formed on the surfaces of the photoconductor drums 111-114 are then transferred to the sheet S fed by the paper feed section 400 at the transfer section N2, and are then fixed onto the sheet S by being heated and pressed by the rotatable heating member 107 and pressure member 108. The sheet S on which the image has been formed is then discharged from the image forming apparatus 100 by the paper discharge rollers 109 and 110, and loaded onto the paper discharge tray 104.

<Paper feeding operation by paper feeding unit>
Fig. 2A is a schematic cross-sectional view illustrating the configuration of the paper feed unit 400 in a state where the pick roller 402 is not in contact with the sheet S, and Fig. 2B is a schematic cross-sectional view illustrating the configuration of the paper feed unit 400 in a state where the pick roller 402 is in contact with the sheet S. As shown in Figs. 2A and 2B, the paper feed unit 400 of this embodiment can come into contact with or separate from the sheet S stacked on the paper feed tray 401 by moving in the directions of the arrows R1 and R2 shown in the drawings.

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

As shown in FIG. 2B, when the sheet S loaded on the paper feed tray 401 is to be fed to the transfer section N2, the controller (not shown) controls the support member 406 to rotate in the direction of the arrow R1 shown in the figure. This brings the pick roller 402 into contact with the top surface 416 of the sheet material S loaded on the paper feed tray 401, making it possible to feed the sheet S.

When the sheet S feeding operation starts, the pick roller 402 is driven to rotate clockwise in FIG. 2A, and the sheet S is fed toward the separation section Ns. The sheets S fed toward the separation section Ns are guided to the separation section Ns by the nip guide 420, and then separated one by one by the feed roller 403 and separation roller 421 rotating clockwise in the separation section Ns, and are conveyed to the conveying roller pair 310.

At this time, when only one sheet S is fed toward the separation section Ns by the pick roller 402, the separation roller 421 receives a rotational force from the feed roller 403 via the sheet S and rotates. The separation roller 421 is provided with a torque limiter and is configured to rotate only when it receives a predetermined rotational torque. On the other hand, when two or more sheets S are fed toward the separation section 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 multiple sheets S that have reached the separation section 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 is retained in the separation section 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 sheets S are separated using such a mechanism.

In this embodiment, the separation roller 421 is configured to have a torque limiter, but this is not limited to the above. For example, the separation roller 421 may be configured to rotate in the same direction as the feed roller 403, and when multiple sheets S are fed to the separation section Ns, only the sheets in contact with the separation roller 421 may be transported toward the paper feed tray 401 by the rotation of the separation roller 421. In this case, as in the configuration of this embodiment, it is necessary to use a separation roller 421 in which the frictional force generated between the separation roller 421 and the sheet S in contact with the separation roller 421 is greater than the frictional force generated between the multiple sheets S.

When the pick roller 402 completes the feeding operation of the sheet S toward the separation section Ns, the support member 406 rotates in the direction of the arrow R2 shown in the figure, and the pick roller 402 moves away from the surface of the sheet S until the next feeding operation is performed, resulting in the state shown in FIG. 2(a). Thus, in this embodiment, when feeding the sheet S, the feed tray 401 does not move up and down toward the pick roller 402, but the support member 406 is rotated to raise and lower the pick roller 402 relative to the sheets S stacked on the feed tray 401.

<Configuration of Paper Feeding Section>
Fig. 3(a) is a schematic perspective view for explaining the configuration of the paper feed section 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) for explaining the peripheral configuration of the paper feed unit 430. Fig. 4(a) is a schematic view for explaining the configuration of the paper feed unit 430 detachably arranged in the image forming apparatus 100, and Fig. 4(b) is a schematic view of the paper feed unit 430 when viewed from an angle different from that in Fig. 4(a).

As shown in FIG. 1 and FIG. 3(a)-(b), the paper feed unit 400 in this embodiment is provided rotatably with respect to the side of the image forming apparatus 100, and the paper feed tray 401 is a manual paper feed tray. As shown in FIG. 1 and FIG. 2(a), the paper feed unit 400 further includes an opening/closing unit 30 that supports the paper feed tray 401 and constitutes the housing of the side of the image forming apparatus 100, a rotating shaft 31, and a support tray 32 for supporting the sheets S loaded on the paper feed tray 401. The support tray 32 is configured to expand and contract in the sheet transport direction, and when a sheet S longer than the opening/closing unit 30 in the sheet transport direction is loaded, it is possible to support the end of the sheet S by pulling it out to the upstream side in the sheet transport direction.

The opening/closing unit 30 rotates in the directions of the arrows R3 and R4 around the pivot shaft 31 as the center of rotation to open or close the paper feed unit 400 with respect to the image forming apparatus 100. From the state of FIG. 3(a), the support tray 32 is folded in the sheet conveying direction, that is, stored so that the length is shorter than the opening/closing unit 30, and the opening/closing unit 30 is rotated in the direction of the arrow R4, so that the side of the image forming apparatus 100 is closed. At this time, the opening/closing unit 30 becomes a part that constitutes the housing of the image forming apparatus 100. On the other hand, when the sheet S is conveyed from the paper feed tray 401 to the transfer unit N2, the opening/closing unit 30 is rotated in the direction of the 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. In addition, in this state, the user or service person can access the paper feed unit 430, and the user or service person can attach and detach the paper feed unit 430.

Next, the configuration of the paper feed unit 430 for conveying the sheet S will be described with reference to Figures 4(a) and (b). As shown in Figure 4(a), the feed roller 403 is provided on a 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 rotated by a driving force transmitted from a driving source (not shown) of the main body of the image forming apparatus 100 via a driving shaft 410.

The pick roller 402 is provided on a 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 a support member 406 and a paper feed cover 407. When the feed roller 403 is driven to rotate, the pick roller 402 is driven to rotate by the driving force transmitted from the gear 405a to the gear 404a via an idler gear, which will be described later.

In Figs. 4(a) and (b), the idler gear cannot be seen because it is covered by cover portion 406a provided on support member 406. The configuration of paper feed unit 430, including the configuration of the idler gear, will be described in detail below with reference to Figs. 5(a) and (b). Fig. 5(a) is a schematic perspective view showing the state in which paper feed cover 407 has been removed from paper feed unit 430. Fig. 5(b) is a schematic perspective view showing paper feed unit 430 disassembled into pick roller unit 431, feed roller unit 432, and paper feed cover 407.

As shown in FIG. 5(a), in this embodiment, three idler gears 412, 413, and 414 (third gears) are rotatably mounted on the support member 406 as drive couplings to transmit the rotational drive force from the gear 405a to the gear 404a.

As shown in FIG. 5B, the feed roller unit 432 is composed of 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 of the drive shaft 410 in the direction of the rotation axis, and the feed roller core 405 is provided at the other end of the drive shaft 410 in the direction of the rotation axis. When a driving force is transmitted to the drive coupling 411 from a drive source (not shown) provided in the main body of the image forming apparatus 100, the drive coupling 411, the drive shaft 410, and the feed roller core 405 rotate together, causing the feed roller 403 to rotate.

The pick roller unit 431 is composed of a cam 409 (drive receiving portion), 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 direction of the rotation axis of the pick roller 402, the cam 409 is provided at one end of the support shaft 408, and the support member 406 is provided at the other end. In this embodiment, the support shaft 408 is configured in a cylindrical shape having a hollow structure, and when the paper feed unit 430 is assembled, the drive shaft 410 is disposed inside the cylinder of the support shaft 408 in the radial direction. Such a configuration of the support shaft 408 and the drive shaft 410 is hereinafter referred to as a double pipe configuration, and will be described in detail later.

Depending on whether or not a driving force is transmitted from a driving source (not shown) provided in the 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 together in the direction of the arrow R1 or the arrow R2 in FIG. 5B. This switches the state of the pick roller 402 between abutting against the sheet S or separating from it, as described in FIGS. 2A-B. Here, the drive transmission mechanism for driving the drive coupling 411 to rotate and the drive transmission mechanism for driving the cam 409 are provided separately. In other words, the drive transmission can be controlled at different times for the rotational drive operation of the feed roller 403 and the pick roller 402 and the swinging operation of the pick roller 402.

Figure 6 is a schematic diagram for explaining the configuration of the support member 406. As shown in Figure 6, the support member 406 has cylindrical shaft portions 406b, 406c, 406d, 406e, and 406f. A support shaft 408 is attached to the shaft portion 406b, and the shaft portion 406c rotatably supports the pick roller core 404. In addition, the shaft portions 406d, 406e, and 406f rotatably support three idler gears 412, 413, and 414.

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

2B, part A is the gear meshing part between gear 404a and idler gear 414, and part B is the gear meshing part between idler gear 412 and idler gear 413. As shown in FIG. 2B, when pick roller 402 and feed roller 403 rotate clockwise during paper feeding, the gear meshing parts such as parts A and B rotate in a winding direction that winds foreign matter into the paper feeding unit 430. More specifically, the winding direction refers to the direction from cover part 406a toward paper feed cover 407 when viewed from the direction of the rotation axis of feed roller 403 shown in FIG. 2B.

If foreign matter gets into the gear meshing portion as described above during the feeding operation of the sheet S by the paper feed unit 430, the gear tooth surface may become easily worn or abnormal noise may occur at the gear meshing portion. In this embodiment, by providing a 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 prevent foreign matter from getting into the drive connection portion of the paper feed unit 430.

In addition, by providing the cover portion 406a, it is possible to prevent foreign matter from entering the drive connection portion not only during paper feeding operation, but also when a service technician or user removes the paper feed unit 430 from the image forming apparatus 100, for example, as shown in FIG. 4(b). When a service technician or user attaches or detaches the paper feed unit 430, or while the paper feed unit 430 is placed on a workbench, there is a possibility that foreign matter may enter the gear meshing portion. Even in such a case, the cover portion 406a covers the drive connection portion, thereby preventing foreign matter from entering.

In this embodiment, three idler gears are provided between gear 405a and gear 404a, but the number of idler gears is not limited to three. Any number of idler gears may be used as long as the rotational drive force from feed roller 403 can be transmitted to pick roller 402.

In addition, in this embodiment, the cover portion 406a covers the position where the gear meshing portion rotates in the winding direction, but it is not necessary for the configuration to cover all of the gear meshing portions of the paper feed unit 430. As long as the configuration covers at least one gear meshing portion that rotates in the winding direction, it is possible to obtain the effects of the configuration of this embodiment.

In this embodiment, the cover portion 406a is provided integrally with the support member 406. This configuration makes it possible to reduce the number of parts and cut costs. However, the configuration in which the cover portion 406a is provided is not limited to this, and the cover portion may be provided by a member formed separately from the support member 406. In this case, since the cover portion only needs to be configured to cover at least a portion of the drive connection portion, it may be provided on the support member 406 or the paper feed cover 407, or it may be provided on another member as long as it does not affect the operation of the paper feed unit 430.

In addition, in this embodiment, a gear is used as the driving means for transmitting the rotation of the feed roller 403 to the pick roller 402, but this is not limited, and the drive may be transmitted by a rotating member such as a pulley or a belt. Furthermore, in this embodiment, a separation method using a separation roller equipped with a torque limiter is 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.

In this embodiment, the configuration of the paper feed unit 430 that is a paper feed section 400 provided on the side of the image forming apparatus 100 and that transports the sheet S from the manual paper feed tray 401 has been described. In this configuration in which the sheet S is transported from the rotatable manual paper feed tray 401, the paper feed tray 401 is exposed to the outside of the image forming apparatus 100 during image formation, so that foreign matter such as paper dust is likely to get mixed into the paper feed unit 430, making it easier to obtain the effects of this embodiment. However, this is not limited to this, and even if the paper feed section is a drawer-type paper feed tray that is detachable from the image forming apparatus 100 and is provided inside the image forming apparatus 100, the configuration of this embodiment can be adopted and the same effects as this embodiment can be obtained.

[Double pipe configuration]
Next, 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 with reference to Figures 4(a)-(b), 5(a)-(b), and 7. Figure 7 is a schematic diagram for explaining a paper feed unit 530 as a comparative example of this embodiment. Note that, except for the configuration of the paper feed unit 530 being different from that of the paper feed unit 430 in this embodiment, the comparative example is substantially the same as this embodiment in other configurations such as the image forming apparatus. Therefore, in the following description of the comparative example, the same reference numerals are used for configurations and operations similar to those of this embodiment, and description thereof will be omitted.

The comparative example paper feed unit 530 has a feed roller 503, a pick roller 502, and a support member 550, and is configured such that the pick roller 502 rotates when the rotational drive of the feed roller 403 is transmitted. The support member 550 rotatably supports the pick roller core 552, idler gears 554, 555, 556, and the feed roller core 553. A drive gear 557 is provided at the end of the drive shaft 510 for rotating the feed roller 503, and the drive shaft 510 is rotatably positioned in the drive section of the main body of the image forming apparatus and cannot be attached to or detached from the main body of the image forming apparatus. Therefore, in the configuration of the comparative example, the support member 550 cannot be attached to or detached from the main body of the image forming apparatus either.

The pick roller core 552 as the support for the pick roller 502 and the feed roller core 553 as the support for the feed roller 503 are positioned so that the movement of the feed roller 503 in the direction of the rotation axis is restricted by the retainer 551. The idler gear 556 is positioned so that the movement of the feed roller 503 in the direction of the rotation axis is restricted by the pick roller core 552. Similarly, the idler gear 554 is positioned so that the movement of the feed roller 503 in the direction of the rotation axis is restricted by the feed roller core 553.

The movement of the idler gear 555 in the direction of the rotation axis of the feed roller 503 is restricted by the idler gear 556. Therefore, in the configuration of the comparative example, when replacing the pick roller 502 and the feed roller 503, it is necessary to remove the retainer 551 from the support member 550, and then remove the pick roller core 552 and the feed roller core 553 from the support member 550 and replace them. At this time, the idler gears 554, 555, and 556 can be removed because their positions are no longer restricted by the pick roller core 552 and the feed roller core 553.

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, the gears are adjusted in phase so that the gear 552a at the end of the pick roller core 552 and the gear 553a at the end of the feed roller core 553 mesh with the idler gears 554 and 556, respectively.

At the end of the support member 550 of the comparative example, a cam member 550a is provided which is driven by receiving force from a drive unit (not shown) of the main body of the image forming apparatus. The cam member 550a has the same function as the cam 409 of this embodiment, and the support member 550 can be oscillated by transmitting a driving force to the cam member 550a from a driving source (not shown) provided in the main body of the image forming apparatus.

As shown in FIG. 7, in the configuration of the comparative example, it is necessary to secure space C, indicated by a dotted line, in order to swing support member 550 and bring pick roller 502 into contact with sheet S. On the other hand, in this embodiment, as shown in FIGS. 4(a)-(b), support shaft 408 is made into a hollow cylindrical shape and drive shaft 410 is provided inside the cylinder of support shaft 408, so that no member is placed in space C in the comparative example and there is no need to secure space C. In this embodiment, the pick roller 402, feed roller 403, and three idler gears are configured as a single unit by the double pipe configuration of support shaft 408 and drive shaft 410.

In the comparative example, since it was necessary to secure space C as shown in FIG. 7, there were limitations on the arrangement and size of the regulating member 417 (shown in FIG. 3A) that regulates the end in the sheet width direction of the sheets S loaded on the paper feed tray 401. Specifically, since it was necessary to secure space C, it was difficult to arrange the regulating member 417 downstream of the pick roller 502 in the sheet transport direction.

In contrast, in this embodiment, since there is no need to provide space C due to the double pipe configuration, it is possible to position the regulating member 417 downstream of the pick roller 402 in the sheet transport direction, which improves the design freedom of the device configuration. In addition, by positioning the regulating member 417 downstream of the pick roller 402 in the sheet transport direction, the regulating member 417 can more effectively suppress skewing of the sheet S when the sheet S is transported by the pick roller 402 and the feed roller 403.

In addition, according to the configuration of this embodiment, the cam 409 and the drive coupling 411 are configured to be detachable with respect to the drive section (not shown) of the main body of the image forming device 100 in the direction of the rotation axis of the feed roller 403. In other words, the paper feed unit 430 can be attached to and detached from the image forming device 100 by moving it in the direction of the rotation axis of the feed roller 403.

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 at the same time. In addition, the paper feed unit 430 is configured so that the idler gears do not come off individually, so the paper feed unit 430 can be replaced without worrying about the meshing of the gears 404a and 405a with the idler gears, improving the workability of users and service personnel.

In addition, in the configuration of the comparative example, when replacing the pick roller 502 and feed roller 503 from the image forming device, the user or serviceman had to perform the work with their hands interfering with the image forming device. On the other hand, in this embodiment, after removing the paper feed unit 430 from the image forming device 100, it is possible to remove and replace the pick roller 402 and feed roller 403 from the paper feed unit 430 in a large space, which improves workability compared to the comparative example.

Furthermore, in the configuration of the comparative example, the cam member 550a for swinging the support member 550 is arranged upstream of the feed roller 503 in the sheet conveying direction. Therefore, it is necessary to provide a space for arranging a drive source (not shown) that transmits a drive force to the cam member 550a upstream of the feed roller 503 in the sheet conveying direction, and the main body of the image forming apparatus needs to be large upstream of the sheet conveying direction. On the other hand, according to the double pipe configuration of this embodiment, the cam 409 is arranged near the support shaft 408 that contains the drive shaft 410, so that the drive source for driving the cam 409 can be arranged near the position where the feed roller 403 is provided in the sheet conveying direction. As a result, it is not necessary to provide a drive source for driving the cam 409 upstream of the feed roller 403 in the sheet conveying direction, and the main body of the image forming apparatus 100 can be prevented from becoming large.

In the above explanation, the double pipe configuration has been described in detail, but even in the comparative example of the feed unit 530 that does not have a double pipe configuration, it is possible to adopt the cover configuration described in this embodiment. In other words, the double pipe configuration is not essential to obtain the effect of preventing foreign matter from entering the drive connection portion of the feed unit 430 described in this embodiment. However, by using a double pipe configuration, it is possible to obtain the effect described above in addition to the effect of preventing foreign matter from entering.

401: Paper feed tray 402: Pick roller 403: Feed roller 406: Support member 406a: Cover portion 412: Idler gear 413: Idler gear 414: Idler gear 420: Nip guide

Claims (8)

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. The sheet conveying means according to claim 1, characterized in that the diameter of the tip of the teeth of the at least one idler gear is smaller than the diameter of the tip of the teeth of the first gear and the diameter of the tip of the teeth of the second gear. The sheet conveying device according to claim 2, characterized in that 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. 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. 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. 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. 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 . 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.

Images