Paper ejection device and image forming apparatus

Abstract

To provide a paper discharging device capable of preventing paper jams during switchback (reverse rotation), and an image forming apparatus.SOLUTION: A paper discharge device according to the present disclosure includes: a conveyance path for conveying a sheet on which an image is recorded; a paper discharge tray from which the sheet conveyed through the conveyance path is discharged; a driving roller for rotating and driving; a driven roller for abutting and following the driving roller; and a rotating member provided around the driven roller, wherein the sheet is sandwiched between the abutting parts of the driving roller and the driven roller and discharged to the paper discharge tray, and the rotating member is interlocked and rotated when the driven roller is rotated, stored in the conveyance path side of the driven roller, interlocked and rotated when the driven roller is rotated in reverse, and drawn out to the paper discharge tray side.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present disclosure relates to a sheet discharge device and an image forming apparatus.

Background Art

[0002] Conventionally, sheet discharge devices have been disclosed.

[0003] For example, Patent Document 1 discloses a sheet discharge device configured to prevent printed sheets from entering the inside of the apparatus. In this device, to prevent printed sheets from entering the inside of the apparatus, a protruding member 28 is provided that is fixed so as not to interfere with the discharge path X of sheets discharged from discharge rollers 17a and 17b, but to interfere with the return path Z along which discharged sheets return to the discharge roller 17a and 17b side.

Prior Art Literature

Patent Literature

[0004]

Patent Document 1

Summary of Invention

Problem to be Solved by Invention

[0005] Incidentally, in order to improve the stacking performance of discharged sheets, a kicking sponge (stiffening member) is provided at an end of a driven roller. The diameter of the kicking sponge is larger than that of the driven roller, and sponge or rubber is often used therefor. This allows the sheet to be curved in the axial direction of the driven roller, giving stiffness to the sheet itself.

[0006] However, when a discharged sheet is bent halfway, conveyance of the sheet ends with an end of the sheet in contact with the driven roller, and when the next sheet undergoes double-sided printing, a paper jam may occur when the stiffening member pulls back the preceding sheet at the timing when the driven roller switches back (rotates reversely). In addition, when no stiffening member is provided, the preceding sheet is pulled back to the driven roller.

[0007] Therefore, in view of the above problems, this disclosure aims to provide a paper ejection device and an image forming apparatus capable of preventing paper jams during switchback (reverse rotation). [Means for solving the problem]

[0008] One aspect of the present disclosure includes a transport path for transporting a sheet on which an image is recorded, a paper output tray from which the sheet transported along the transport path is discharged, a drive roller that is driven to rotate, a driven roller that abuts against and is driven by the drive roller, and a rotating member provided around the driven roller, wherein the sheet is held between the contact portion of the drive roller and the driven roller and discharged to the paper output tray, the rotating member rotates in conjunction with the rotation of the driven roller and is housed on the transport path side of the driven roller, and rotates in conjunction with the reverse rotation of the driven roller and is pulled out towards the paper output tray side. [Effects of the Invention]

[0009] As described above, this disclosure provides a paper ejection device and an image forming apparatus that can prevent paper jams during switchback (reverse rotation). [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 is a schematic diagram showing the internal structure of the image forming apparatus according to this disclosure, viewed from the front. [Figure 2] Figure 2 is a perspective view of the paper output tray located above the image forming unit. [Figure 3] Figure 3 is a cross-sectional view of the paper output tray located above the image forming unit. [Figure 4] Figure 4 is a cross-sectional view showing a paper ejection device without a rotating member, illustrating how the paper is ejected. [Figure 5] Figure 5 is a cross-sectional view showing a paper ejection device without a rotating member, illustrating how the paper switches back. [Figure 6]FIG. 6 is an enlarged view of a rotating member provided around a driven roller, showing a state during sheet discharge. [Figure 7] FIG. 7 is a side view of FIG. 6. [Figure 8] FIG. 8 is a front view of FIG. 6. [Figure 9] FIG. 9 is an enlarged view of a rotating member provided around a driven roller, showing a state during switchback. [Figure 10] FIG. 10 is a side view of FIG. 9. [Figure 11] FIG. 11 is a front view of FIG. 9. [Figure 12] FIG. 12 is a front view showing a driven roller not provided with a curling correction member. [Figure 13] FIG. 13 is a perspective view showing that a torque limiter is provided on a rotating gear. [Figure 14] FIG. 14 is an explanatory diagram of the torque limiter. [Figure 15] FIG. 15 is an explanatory diagram of the torque limiter. [Figure 16] FIG. 16 is an explanatory diagram of the torque limiter. [Figure 17] FIG. 17 is a perspective view showing that a rotation restricting portion is provided around a rotating member, and is a view of FIG. 2 seen from the left. [Figure 18] FIG. 18 is a perspective view showing that a rotation restricting portion is provided around a rotating member, and is a view of FIG. 2 seen from the right. [Figure 19] FIG. 19 is a perspective view showing that a rotation restricting portion is provided around a rotating member, and is a view showing only the periphery of the rotating member. DETAILED DESCRIPTION OF EMBODIMENTS

[0011] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the drawings. It should be noted that the present embodiment described below does not unduly limit the content of the present disclosure described in the claims, and not all of the configurations described in the present embodiment are necessarily essential as solutions for the present disclosure.

[0012] (Image forming apparatus) An image forming apparatus 100 according to the present disclosure will be described with reference to FIG. 1. FIG. 1 is a schematic diagram showing the internal structure of the image forming apparatus according to the present disclosure as viewed from the front side. In the image forming apparatus 100, among the horizontal directions when viewed from the front side, the left side is defined as the left direction, and the right side is defined as the right direction. Further, among the depth directions when viewed from the front side, the front side (near side) of the image forming apparatus 100 is defined as the front direction, and the back side (far side) is defined as the rear direction. Further, in the image forming apparatus 100, the bottom side is defined as the downward direction, and the opposite side is defined as the upward direction.

[0013] As shown in FIG. 1, the image forming apparatus 100 includes an image forming apparatus main body 110, an image reading apparatus 200, a paper discharge apparatus 300, a paper feeding apparatus 400, and a manual feed unit 510.

[0014] An image reading apparatus 200 is provided on an upper portion of the image forming apparatus main body 110. The image reading apparatus 200 is an apparatus that reads an image of a document G. The image reading apparatus 200 includes a document placement table 221 formed of a transparent material on which a document G is placed. A document pressing cover 218 that is openably and closably attached via a hinge or the like is provided above the document placement table 221. A document supply tray 220 is provided on an upper surface of the document pressing cover 218, and an auto document feeder (ADF), which is not shown, is provided inside thereof. The ADF automatically feeds the documents G placed on the document supply tray 220 one by one to an image reading position 222.

[0015] The image reading device 200 incorporates an image reading unit 226 that reads an image from the original document G. The image reading unit 226 includes a light source, multiple mirrors, an imaging lens, and a line sensor (not shown). The image reading device 200 exposes the original document G with light emitted from the light source and guides the reflected light from the original document G to the imaging lens using the multiple mirrors. The imaging lens then images the reflected light onto the photodetector of the line sensor. The line sensor detects the brightness or chromaticity of the reflected light imaged onto the photodetector and generates image data based on the original document G. As the line sensor, for example, a CCD (Charge Coupled Device) or CIS (Contact Image Sensor) can be used.

[0016] Below the image reading device 200 is a paper feed device 400 comprising a paper ejection device 300, a paper feed cassette 410, and a sheet supply unit 420. The paper ejection device 300 will be described in detail later.

[0017] The paper feed cassette 410 holds sheets P (paper) to be supplied to the main body 110 of the image forming apparatus. The image forming apparatus 100 is configured to hold 500 sheets P in the paper feed cassette 410. The sheets P stored in the paper feed cassette 410 are supplied to the main body 110 of the image forming apparatus by the sheet supply unit 420.

[0018] The sheet supply unit 420 has a drawing roller 421, a supply roller 422, and a separation roller 423. The drawing roller 421 is rotationally driven to pull the sheets P contained in the paper feed cassette 410 from above and feed them toward the supply roller 422 and the separation roller 423. The separation roller 423 is positioned opposite the supply roller 422. When supplying sheets P to the main body of the image forming apparatus 110, the separation roller 423 is maintained in a state of pressing against the supply roller 422. Then, the separation roller 423 is rotationally driven to separate and transport the sheets P one by one between the supply roller 422 and the separation roller. Alternatively, the supply roller 422 may also serve as the drawing roller 421 without providing a separate drawing roller 421. In this configuration, the supply roller 422 is rotationally driven to pull the sheets P from the paper feed cassette 410.

[0019] In Figure 1, for the sake of explanation, only one paper feed cassette 410 and one sheet supply unit 420 are shown. However, the image forming apparatus 100 may be configured with three paper feed cassettes 410 arranged in multiple stages in the vertical direction, with a sheet supply unit 420 provided in each paper feed cassette 410.

[0020] Furthermore, a manual feed unit 510 having a sheet storage section is provided on the lower right side of the main body 110 of the image forming apparatus. The manual feed unit 510 supplies sheets P that cannot be set in the paper feed cassette 410 of the paper feed device 400 to the image forming apparatus 100.

[0021] The sheets P stored in the paper feed cassette 410 of the paper feed device 400 and the sheets P stored in the sheet storage section of the manual feed unit 510 are sent via the transport roller 12a to the sheet transport path W1 (transport path) of the main body of the image forming apparatus 110.

[0022] The image forming apparatus 100 includes an image forming unit 102 and a sheet transport system 103.

[0023] The image forming unit 102 comprises an exposure unit 1, a developing unit 2, a photosensitive drum 3 acting as an electrostatic latent image carrier, a cleaning unit 4, a charging device 5, a primary transfer device 6, a fixing unit 7, and a secondary transfer device 10. The image forming unit 102 records and forms an image on a sheet P transported from a paper feed cassette 410 or the like, and discharges the paper into a paper output tray 14. Image data for forming an image on the sheet P can be image data read from the original document G by the image reading unit 226 or image data transmitted from an external computer or the like.

[0024] Meanwhile, the sheet transport system 103 is equipped with a sheet transport path W1. In the sheet transport path W1, the register roller 13, the transfer roller 10a provided by the secondary transfer device 10, the fixing roller 71 and pressure roller 72 provided by the fixing unit 7, and the driven roller 31 are arranged from the transport roller 12a toward the output tray 14.

[0025] When image formation is performed in the image forming apparatus 100, the charging device 5 uniformly charges the surface of the photoreceptor drum 3 in the image forming unit 102. The exposure unit 1 then laser-exposes the charged surface of the photoreceptor drum 3 based on the image data. This forms an electrostatic latent image on the photoreceptor drum 3. The exposure unit 1 can be configured as a laser scanning unit equipped with a laser emitter and a reflective mirror (not shown).

[0026] The electrostatic latent image formed on the photoreceptor drum 3 is developed in the developing unit 2 and manifested as a toner image. In other words, the developing unit 2 includes a developing tank for containing toner and a developing roller that functions as a developer carrier (not shown). The developing unit 2 supplies toner to the surface of the photoreceptor drum 3 and manifests the electrostatic latent image formed on the surface of the photoreceptor drum 3 with the toner. A toner concentration detection sensor (not shown) is provided inside the developing tank to detect the toner concentration. When the toner concentration detected by this toner concentration detection sensor falls below a predetermined value, toner is supplied to the developing tank from a toner supply device (not shown).

[0027] The toner image on the photoreceptor drum 3 is transferred in the primary transfer device 6 onto an intermediate transfer belt 6c that is stretched between the first roller 6a and the second roller 6b of the primary transfer device and rotates along the circumferential direction E. The toner image on the intermediate transfer belt 6c is then transported to the secondary transfer device 10.

[0028] Meanwhile, the sheet P supplied from the paper feed device 400 or the manual feed unit 510 is transported through the sheet transport path W1, via the transport roller 12a, to the register roller 13. Next, the sheet P is transported by the register roller 13 to the transfer roller 10a at the timing when the sheet P and the toner image on the photoreceptor drum 3 are aligned. The toner on the photoreceptor drum 3 is then transferred onto the sheet P by the transfer roller 10a. After that, the sheet P passes through the fuser roller 71 and pressure roller 72 in the fuser unit 7, and is discharged to the output tray 14 via the drive roller 31 and driven roller 32.

[0029] The fixing unit 7 includes a fixing roller 71 and a pressure roller 72, and is positioned above the image forming unit 102. The fixing roller 71 is set to a predetermined fixing temperature (for example, 160°C), and as the sheet P passes through the nip region (fixing nip portion) between the fixing roller 71 and the pressure roller 72, the toner image transferred to the sheet P is melted, mixed, and pressed. In this way, the toner image is heat-fixed to the sheet P.

[0030] Furthermore, when image formation is performed not only on the front surface of sheet P but also on the back surface of sheet P, sheet P is transported in the reverse direction from the driven roller 31 through the inverted sheet transport path W2 (transport path). This is called switchback. In the inverted sheet transport path W2, sheet P passes through two inverted transport rollers 12b located at predetermined intervals apart, and is then guided back to the register roller 13 with its front and back surfaces reversed. Then, just as with the front surface of sheet P, a toner image is formed and fixed on the back surface of sheet P. After that, sheet P is discharged to the output tray 14.

[0031] After development and image transfer, toner remains on the surface of the photoreceptor drum 36. Therefore, the image forming apparatus 100 is equipped with a cleaning unit 4 that has a cleaning blade or the like that contacts the surface of the photoreceptor drum 36, and is configured to remove the toner remaining on the surface of the photoreceptor drum 36 using this cleaning unit 4.

[0032] Furthermore, the image forming apparatus 100 having the above-described configuration includes a control unit, which includes a CPU and memory (not shown). The control unit is configured to transmit control signals to various parts of the image forming apparatus 100 in response to input operations on the operation panel, causing the image forming apparatus 100 to perform various operations.

[0033] The image forming apparatus 100 was configured to include a paper feeder 400 and a manual feed unit 510. However, the image forming apparatus 100 may also be configured to include an external paper feeder, from which sheets P are fed into the sheet transport path W1.

[0034] (Paper ejection device) Next, the paper ejection device 300 according to this disclosure will be described. In the figure, the left side is the ejection side (paper output tray side), and the right side is the switchback side (paper transport path side). The paper ejection device 300 according to this disclosure comprises an image forming apparatus main body 110, a paper output tray 14, a driven roller 32, and a rotating member 35. The configuration of the paper ejection device 300 according to this disclosure will be described below with reference to Figure 2 and subsequent figures. As an example of the paper ejection device 300 according to this disclosure, a paper ejection device built into the upper part of the image forming apparatus 100 will be used, but it is not limited to this. For example, the paper ejection device 300 may be provided separately from the image forming apparatus 100.

[0035] Figure 2 is a perspective view of the paper output tray 14 located above the image forming unit 102. The paper output tray 14 is provided on the main body 110 of the image forming apparatus. Figure 3 is a cross-sectional view of the paper output tray 14 located above the image forming unit 102. As shown in Figures 2 and 3, the driven roller 32 is provided on the paper output tray 14 and is located on the discharge side of the paper output tray 14. The rotating member 35 is provided around the driven roller 32. The arrows in Figure 3 indicate the discharge and switchback of the sheet P, with the left arrow indicating the discharge of the sheet P and the right arrow indicating the switchback of the sheet P.

[0036] If the rotating member 35 is not provided, as shown in Figure 4, when the paper is ejected, the next sheet P2 comes into contact with the driven roller 32 and the backing member 33 along with the ejected sheet P1. Then, as shown in Figure 5, when the paper is switched back, the previous sheet P1 is pulled back by the backing member 33. The sensor continues to detect the next sheet P2 and the pulled-back sheet P1, and if the specified time is exceeded, a paper jam occurs. Also, if there is no backing member, the previous sheet is pulled back by the driven roller.

[0037] Therefore, the paper ejection device 300 according to this disclosure can prevent paper jams during switchback by providing a rotating member 35 located around the driven roller 32. This will be described in detail below.

[0038] Figure 6 is an enlarged view of the rotating member 35 provided around the driven roller 32, which is in contact with and driven by the drive roller 31, and shows the state during discharge. Figure 7 is a side view of Figure 6. Figure 8 is a front view of Figure 6. As shown in Figures 6, 7, and 8, the rotating member 35 is provided on the pivot shaft 36. As shown in Figure 7, during discharge, the sheet P is sent out in the direction of the arrow, and at the same time, the pivot shaft 36 rotates to the right, causing the tip 35a of the rotating member 35 to move to the right and be housed inside the diameter of the driven roller 32 or the backing member 33. At this time, the rotating member 35 rotates in conjunction with the rotation of the driven roller 32. To achieve this, an intermediate gear 38, which will be described later, can be provided. In Figure 6, etc., a backing member 33, which is larger than the diameter of the driven roller 32, is provided on the outside of the driven roller 32 along the direction of the rotation axis of the driven roller 32. The backing member 33 is made of sponge or rubber. Furthermore, the backing member 33 can bend the paper P in the direction of the driven roller axis 41, thereby giving the paper P itself backing.

[0039] As shown in Figures 6, 7, and 8, the rotating member 35 is housed on the side of the driven roller 32 or the waist support member 33, so it does not affect the sheet P during discharge.

[0040] On the other hand, during a switchback, as shown in Figures 9, 10, and 11, the sheet P is fed in the direction of the arrow, and at the same time, the pivot shaft 36 rotates counterclockwise. In particular, as shown in Figure 10, the tip 35a of the pivot member 35 moves to the left and is pulled out towards the switchback side (left side). At this time, the pivot member 35 rotates in conjunction with the reverse rotation of the driven roller 32 and is pulled out towards the paper output tray 14, which is the switchback side.

[0041] In this way, the rotating member 35 moves from side to side during discharge and switchback. During switchback, the rotating member 35 is pulled out towards the output tray 14, acting as a stopper for the next sheet, preventing the sheet P from touching the driven roller 32 or the stiffening member 33, thereby preventing paper jams. Furthermore, paper jams can be prevented even with sheets that are not stiff or sheets that contain moisture.

[0042] Furthermore, as shown in Figure 10, it is preferable that, during switchback, the tip portion 35a of the rotating member 35 is formed to be the same height N as the driven roller shaft 41 of the driven roller 32, or higher than the height N of the driven roller shaft 41 of the driven roller 32, in the direction of the rotation axis of the driven roller 32. In this way, during switchback, it is possible to prevent the next sheet of paper from touching the driven roller 32, etc., and to reliably prevent paper jams.

[0043] Furthermore, as shown in Figure 7, it is preferable that the tip portion 35a of the rotating member 35 does not protrude outward (to the left) on the paper output tray side from the driven roller 32 or the outer peripheral surface M of the backing member 33 provided on the driven roller 32 when it rotates in conjunction with the driven roller 32 and is housed inside the driven roller 32. In this way, the sheet P can be discharged when it is discharged.

[0044] On the other hand, as shown in Figure 10, it is preferable that the tip portion 35a of the rotating member 35 protrudes outward from the outer peripheral surface M of the driven roller 32 when it is pulled out toward the paper output tray 14 side in conjunction with and rotates during the switchback of the driven roller 32. This prevents paper jams of the sheet P during the switchback.

[0045] Furthermore, as shown in Figure 10, it is preferable that, during switchback, the tip portion 35a of the rotating member 35 is formed to be the same as the height N of the driven roller shaft 41 of the driven roller 32, or higher than the height N of the driven roller shaft 41 of the driven roller 32.

[0046] Furthermore, as shown in Figure 10, during switchback, the rotating member 35 preferably has an arc portion 35b in part, and the center Oa of the circle of the arc portion 35b coincides with the center Oa of the circle of the driven roller 32. In other words, the center Oa of the circle of the arc portion 35b coincides with the center Oa of the driven roller 32. Also, the center Oa of the circle of the arc portion 35b coincides with the center Oa of the circle of the driven roller 32 and / or the center of the circle of the backing member. Note that the arc portion 35b is arc-shaped and exists in an arc shape around the driven roller shaft 41. Alternatively, the rotating member 35 may not have an arc portion 35b and may be straight or L-shaped.

[0047] Furthermore, as shown in Figure 10, during switchback, it is preferable that the center Ob of the pivot axis 36 of the rotating member 35 is positioned on the conveyor side (right side) of the center Oa of the driven roller axis 41 of the driven roller 32 in the direction of the rotation axis of the driven roller 32. Also, during switchback, it is preferable that the center Ob of the pivot axis 36 of the rotating member 35 is positioned below the center Oa of the driven roller axis 41 of the driven roller 32.

[0048] Furthermore, as shown in Figure 11, it is preferable that the rotating members 35 are provided adjacent to both sides of the driven roller 32 along the rotation axis direction of the driven roller 32. It is also preferable that each of the rotating members 35 provided adjacent to both sides of the driven roller 32 rotates together when the rotation shaft 36 rotates. Furthermore, it is preferable that there are multiple rotating members 35 provided adjacent to both sides of the driven roller 32.

[0049] Figure 12 is a front view showing a driven roller 32 without a backing member. As shown in Figure 12, the driven roller 32 does not necessarily need to have a backing member. In this configuration as well, the positional relationship between the backing member and the tip 35a of the rotating member 35 is as described above.

[0050] Figure 13 is a perspective view showing that a torque limiter is provided on the rotating gear 39. As shown in Figure 13, it is preferable that the system further comprises a rotating shaft 36 that rotates the rotating member 35 and a rotating gear 39, and that a torque limiter is provided around the rotating gear 39 to limit the rotation of the rotating shaft 36.

[0051] As shown in Figure 13, the rotationally driven drive roller 31 rotates the rotating member 35 via the drive roller shaft 40, drive roller gear 37, intermediate gear 38, rotating gear 39, and rotating shaft 36. Therefore, in order to properly press the rotating member 35 inward due to its rotation, it is preferable to provide a torque limiter around the rotating gear 39.

[0052] The torque limiter comprises a gear 39a, a torque limiter 39b, and a rotation stopper 39c for the gear 39a and torque limiter 39b, as shown in Figure 14. The torque limiter is constructed by attaching the gear 39a shown in Figure 15 to the rotation stopper 39c shown in Figure 16, with the torque limiter 39b attached to it.

[0053] In this way, the rotation of the pivot shaft 36 and the rotation of the pivot member 35 can be restricted, allowing for appropriate pressure to be applied to the back side, and thus more reliably preventing paper jams during switchback.

[0054] Furthermore, as shown in Figure 13, a spring 42 may be provided on the driven roller shaft 41 to restrict the rotation of the rotating member 35. In this way, the rotation of the rotating member 35 can be easily restricted.

[0055] Furthermore, at the moment of the switchback, the rotating member 35 is rotating, so the seat P is pulled back slightly.

[0056] Therefore, the diameter of the drive roller gear 37 is made larger than the diameter of the rotating gear 39. By doing so, the operation of the rotating member 35 can be made faster, the amount of retraction can be reduced, and paper jams can be prevented more effectively.

[0057] On the other hand, by using the rotating gear 39 as the driving source and the driven roller gear 37 as the driven component, the rotating member 35 moves faster due to the backlash of the gear, which reduces the amount of pull-back and further prevents paper jams.

[0058] The drive roller 31 is, for example, a rubber roller, the driven roller 32 is, for example, a resin roller, and the backing member 33 is, for example, a sponge roller.

[0059] Figures 17, 18, and 19 are perspective views showing that a rotation restricting portion 35c is provided around the rotating member 35. Figure 17 is a view of Figure 2 from the left. Figure 18 is a view of Figure 2 from the right, showing the rotation restricting portion 35c. Figure 19 shows only the area around the rotating member 35. As shown in Figures 17, 18, and 19, it is preferable that a rotation restricting portion 35c is provided around the rotating member 35 to restrict rotation beyond a predetermined position during rotation and reverse rotation of the driven roller 32.

[0060] The rotation restricting portion 35c is a projection or rib. A hole 51 is provided in the transport guide 50, and the rotation restricting portion 35c is configured to protrude from there. In this way, the rotation of the rotating member 35 can be easily restricted.

[0061] Based on the above, the paper ejection device 300 according to this disclosure can prevent paper jams during switchback (reverse rotation).

[0062] Although each embodiment and example of this disclosure has been described in detail above, it will be readily apparent to those skilled in the art that many modifications are possible without substantially departing from the novelty and effects of this disclosure. Therefore, all such modifications are included within the scope of this disclosure.

[0063] For example, any term that appears at least once in the specification or drawings alongside a broader or synonymous term may be replaced with that different term anywhere in the specification or drawings. Furthermore, the configuration and operation of the paper ejection device and image forming apparatus are not limited to those described in the embodiments and examples of this disclosure, and various modifications are possible. [Explanation of Symbols]

[0064] 1. Exposure unit, 2. Developing unit, 3. Photoreceptor drum, 4. Cleaning unit, 5. Charging device, 6. Primary transfer device, 7. Fixing unit, 10 Secondary transfer device, 14 Output tray, 31 Drive roller, 32 Driven roller, 33 Support member, 35 Rotating member, 35a Tip (of the rotating member), 35b Arc portion, 35c Rotation restricting portion, 36 Rotating shaft, 37 Drive roller gear, 38 Intermediate gear, 39 Rotating gear, 39a Gear (provided on the rotating shaft), 39b Torque limiter, 39c Rotation stopper, 40 Drive roller shaft, 41 Driven roller shaft, 42 Spring, 50 transport guides, 51 holes, 100 Image forming apparatus, 102 Image forming unit, 103 Sheet transport system, 110 Image forming apparatus main body, 200 Image reading device, 300 paper ejection device, 400 Paper feed device, 410 Paper feed cassette, 420 Sheet supply unit, 510 manual feed unit, M is the outer surface, N is the height of the rotation axis of the driven roller. Oa: Center of the arc (center of the driven roller), Ob: Center of the pivot axis, P sheet (paper), W1: Sheet transport path, W2: Reversing sheet transport path

Claims

1. A transport path for transporting sheets on which images are recorded, A paper output tray from which the sheet transported along the transport path is discharged, A drive roller that rotates around the drive roller shaft, A driven roller that contacts the drive roller and moves in conjunction with the drive roller, rotating around a driven roller shaft provided below the drive roller shaft, A rotating member is provided around the driven roller so as to rotate around a pivot axis provided parallel to the driven roller shaft on the lower side of the driven roller shaft, Equipped with, The sheet is held between the contact portion of the drive roller and the driven roller and discharged to the output tray. The tip of the rotating member is characterized in that it rotates in conjunction with the rotation of the drive roller and is housed inside the outer circumferential surface of the driven roller, and rotates in conjunction with the rotation of the drive roller and protrudes outside the outer circumferential surface of the driven roller toward the discharge tray when the drive roller rotates in the reverse direction.

2. The driven roller is provided with a backing member, and the outer surface of the driven roller is the outer surface of the backing member. The paper discharge device according to claim 1, characterized in that when the tip of the rotating member rotates in conjunction with the rotation of the drive roller and is housed on the transport path side of the driven roller, it does not protrude outward toward the paper discharge tray side beyond the driven roller or the outer peripheral surface of the backing member provided on the driven roller.

3. The rotating member is further provided with a rotating gear on the rotating shaft that rotates the rotating member, A torque limiter is provided around the rotating gear to restrict the rotation of the rotating shaft, and the torque limiter functions when the rotation of the drive roller of the rotating member is restricted to a position where it is rotated inward and housed beyond the outer circumferential surface of the driven roller during rotation, and when the rotation of the drive roller of the rotating member is restricted to a position where it is rotated outward and protrudes beyond the outer circumferential surface of the driven roller during reverse rotation, as described in claim 1 or 2.

4. The paper ejection device according to claim 1 or 2, characterized in that a rotation restricting portion is provided around the rotating member during rotation and reverse rotation of the driven roller, which restricts rotation beyond a predetermined position.

5. A part of the rotating member has an arc-shaped portion, The paper ejection device according to claim 1 or 2, characterized in that, during the switchback, the center of the circle including the arc portion coincides with the center of the circle of the driven roller.

6. The paper ejection device according to claim 1 or 2, characterized in that, in the direction of the rotation axis of the driven roller, the tip of the rotating member is formed to be the same as the height of the rotation axis of the driven roller, or higher than the height of the rotation axis of the driven roller.

7. The paper discharge device according to claim 1 or 2, characterized in that the center of the rotation axis of the rotating member is located on the transport path side of the center of the driven roller axis of the driven roller in the direction of the rotation axis of the driven roller.

8. The paper ejection device according to claim 1 or 2, characterized in that the rotating member is provided adjacent to both sides of the driven roller along the rotation axis direction of the driven roller.

9. The paper ejection device according to claim 1 or 2, characterized in that a support member, which is larger than the diameter of the driven roller, is provided on the outside of the driven roller along the rotation axis direction of the driven roller.

10. An image forming apparatus characterized by comprising a paper ejection device according to claim 1 or 2.

Images