Sheet conveying device and image forming apparatus

Abstract

To prevent a malfunction due to load increase in the rotation direction of switching means.SOLUTION: In a sheet conveyance device which has switching means capable of switching between a first position for guiding a sheet to be conveyed in a first direction and a second position for guiding it in a second direction different from the first direction, the switching means includes: a shaft member extending in the width direction orthogonal to the conveyance direction of a sheet; a guide member inserted in an insertion direction going from one end part toward the other end part of the shaft member with respect to the shaft member, and for guiding the sheet at the first position or at the second position by rotating together with the shaft member; a transmission member inserted in the insertion direction with respect to the one end part of the shaft member supported by a support member for supporting both end parts of the shaft member in a rotatable manner, and for transmitting the force for rotating the shaft member to the shaft member; and a restriction part for restricting the movement of the shaft member in the insertion direction before the guide member, when the shaft member receives a pressing force in the insertion direction by the insertion of the transmission member.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a sheet transport device that transports a sheet, and an image forming apparatus including the same. [Background technology]

[0002] In an electrophotographic image forming apparatus, a latent image formed on an image carrier is developed in an image forming section to form a visible image. This visible image is then transferred to a sheet, and the transferred image is fixed to the sheet by heating and pressurizing it in a fixing device. The sheet with the fixed image is discharged to the outside of the machine by discharge rollers. Alternatively, during double-sided printing, the sheet is reversed and conveyed by a reversing roller, and then re-fed to the image forming section via a double-sided conveying path, where it goes through a transfer and fixing process before being discharged to the outside of the machine by discharge rollers. The discharged sheet is then stacked on a discharge tray.

[0003] In an electrophotographic image forming apparatus, a latent image formed on an image carrier is developed in an image forming section to form a visible image. This visible image is then transferred to a sheet, and the transferred image is fixed to the sheet by heating and pressurizing it in a fixing device. The sheet with the fixed image is discharged to the outside of the machine by discharge rollers. Alternatively, during double-sided printing, the sheet is reversed and conveyed by a reversing roller, and then re-fed to the image forming section via a double-sided conveying path, where it goes through a transfer and fixing process before being discharged to the outside of the machine by discharge rollers. The discharged sheet is then stacked on a discharge tray.

[0004] In such an image forming apparatus, a switching means is provided for guiding the sheet on which the image is fixed by the fixing unit to a first transport path toward the discharge rollers or a second transport path toward the reversing rollers. The switching means is provided at a branch point between the first transport path from the fixing unit to the discharge rollers and the second transport path from the fixing unit to the reversing rollers. Such switching means are used in various places in the image forming apparatus to guide the transported sheet to one of a plurality of transport paths. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2004-315169 A Summary of the Invention [Problem to be solved by the invention]

[0006] Such a switching means may be, for example, configured by assembling three members, a metal shaft member, a resin guide member, and a resin link member. Patent Document 1 describes a configuration in which comb-tooth-shaped guide members are intermittently arranged in the axial direction of the shaft member, and a link member is provided at one end of the shaft member. The switching means rotates the link member using a driving force from a driving source such as a solenoid, thereby rotating the guide member together with the shaft member, and switching the position of the guide member.

[0007] One method for manufacturing a switching means having such a configuration is to insert and assemble three components, a metal shaft member, a resin guide member, and a link member, which are processed separately. By configuring it in this way, the rigidity in the longitudinal direction can be supplemented by the metal shaft member, and a continuous conveying guide surface can be formed by the resin guide member, so that the switching means can be manufactured at low cost without reducing the sheet conveying performance.

[0008] In the switching means having such a configuration, a link member is disposed on one end of the shaft member protruding outward from the support member while both ends of the shaft member on which the guide member is disposed are rotatably supported by the support member. At this time, the link member is inserted in the axial direction (the insertion direction from one end of the shaft member to the other end) into the shaft member supported by the support member. In this case, the insertion of the link member causes the shaft member to move in the axial direction due to an axial pressing force, and the guide member disposed on the shaft member also moves in the same direction.

[0009] Then, the downstream end of the guide member in the insertion direction hits the support member supporting the downstream end of the shaft member, and the gap between the end of the guide member and the support member in the width direction (axial direction) perpendicular to the sheet conveying direction disappears. As a result, the sliding load in the rotation direction of the switching means increases, and malfunction occurs due to the increased load in the rotation direction of the switching means. hand There is a risk of this happening.

[0010] In addition, after the end of the guide member abuts against the support member and the axial movement of the guide member is restricted by the support member, the shaft member may be subjected to the pressing force caused by the insertion of the link member. In this case, the shaft member may move further in the axial direction relative to the guide member whose axial movement is restricted. As a result, the relative positions of the shaft member and the guide member may be shifted.

[0011] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to prevent malfunctions caused by an increase in the load in the rotation direction of the switching means. [Means for solving the problem]

[0012] A representative configuration for achieving the above object is a sheet transporting device having a switching means that can be switched between a first position where a transported sheet is guided in a first direction and a second position where a transported sheet is guided in a second direction different from the first direction, the switching means including: a shaft member extending in a width direction perpendicular to a sheet transport direction; a guide member that is inserted into the shaft member in an insertion direction from one end of the shaft member to the other end thereof and rotates together with the shaft member to guide the sheet at the first position or the second position; a transmission member that is inserted in the insertion direction into one end of the shaft member supported by a support member that rotatably supports both ends of the shaft member and transmits a force that rotates the shaft member to the shaft member; and a switching means that switches between the guide member and the shaft member when the shaft member receives a pressing force in the insertion direction due to the insertion of the transmission member. before hitting the support member and a restricting portion that restricts movement of the shaft member in the insertion direction. Effect of the Invention

[0013] According to the present invention 、 Even if the shaft member is subjected to a pressing force by the insertion of the transmission member, a gap can be secured between the guide member and the support member, and the relative positional deviation between the shaft member and the guide member can be prevented. As a result, the gap necessary for the switching means to rotate is secured, and malfunctions due to an increase in the load in the rotation direction of the switching means can be prevented. [Brief description of the drawings]

[0014] [Figure 1] 1 is a schematic cross-sectional view of an image forming apparatus according to a first embodiment of the present invention; [Diagram 2] FIG. 1 is a perspective view of a discharge section having a switching flapper; [Diagram 3] Cross-sectional view of the discharge section with the switching flapper in the standby position [Figure 4] Cross-sectional view of the discharge section with the switching flapper in the operating position [Diagram 5] Switching flapper parts layout diagram [Figure 6] 1 is a cross-sectional view of an end portion of a switching flapper according to a first embodiment; [Figure 7] Diagram of assembly sequence of switching flapper [Figure 8] Diagram of assembly sequence of switching flapper [Figure 9] 1 is a cross-sectional view of an end portion of a switching flapper in a comparative example; [Figure 10] 1 is a cross-sectional view of an end portion of a switching flapper in a comparative example; [Figure 11] 11 is a cross-sectional view of an end portion of a switching flapper according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Preferred embodiments of the present invention will be described in detail below with reference to the drawings. However, the dimensions, materials, shapes, and relative positions of the components described in the following examples may be changed as appropriate depending on the configuration of the device to which the present invention is applied and various conditions, and are not intended to limit the scope of the present invention to these alone.

[0016] Example 1 An image forming apparatus including a sheet conveying device according to the first embodiment will be described with reference to Fig. 1. Fig. 1 is a cross-sectional view of an image forming apparatus including a sheet conveying device. Here, an intermediate transfer tandem type image forming apparatus in which four color image forming units are arranged side by side on an intermediate transfer belt is illustrated as an example of the image forming apparatus.

[0017] 1 includes an image forming section 140 that forms an image on a sheet, and a sheet conveying section (sheet conveying device) having a switching means described later. Here, as the sheet conveying section, a discharge section 160 having a switching flapper 200 (switching means) that guides a sheet S on which an image has been fixed in a first direction toward a discharge roller 161, or a second direction toward a reversing roller 162 that is different from the first direction, is illustrated.

[0018] First, the conveying process of the sheet S will be described. The sheet S is fed by the sheet feeding section 110 in accordance with the image formation timing of the image forming apparatus. The sheet S fed by the sheet feeding section 110 is conveyed to the skew correction device 120. The sheet S is sent to the secondary transfer section 130 after skew correction and timing correction are performed by the skew correction device 120. The secondary transfer section 130 is a sandwich section for transferring a toner image to the sheet S, which is formed by a secondary transfer inner roller 131 and a secondary transfer outer roller 132 that are substantially opposed to each other. The secondary transfer section 130 transfers a toner image to the sheet S by applying a predetermined pressure force and an electrostatic load bias.

[0019] Next, the process of forming an image sent to the secondary transfer unit 130 at the same timing as the process of conveying the sheet S to the secondary transfer unit 130 will be described. The image forming unit 140 is an image forming unit that forms an image on a sheet, and is mainly composed of a photoconductor 141, an exposure device 142, a developing device 143, and a primary transfer device 144. The exposure device 142 emits light based on a signal of image information sent to the photoconductor 141, whose surface has been uniformly charged in advance by a charging device, and a latent image is formed through a diffraction device or the like as appropriate. The electrostatic latent image thus formed on the photoconductor 141 is developed by the developing device 143 to form a toner image on the photoconductor 141. Thereafter, the toner image formed on the photoconductor 141 is given a predetermined pressure force and an electrostatic load bias by the primary transfer device 144, and is transferred to the intermediate transfer belt 145. In the case of the image forming apparatus 100 shown in FIG. 1, four sets of the image forming units 140 described above are provided, one for yellow Y, one for magenta M, one for cyan C, and one for black Bk.

[0020] Next, the intermediate transfer belt 145 will be described. The intermediate transfer belt 145 is driven to be transported in the direction of arrow A in FIG. 1. Therefore, the above-mentioned yellow Y, magenta M, cyan C, and black Bk are processed in parallel by the image forming units 140. The image forming process for each color is performed at a timing when it is superimposed on the upstream toner image that has been primarily transferred onto the intermediate transfer belt 145. As a result, a full-color toner image is finally formed on the intermediate transfer belt 145 and transported to the secondary transfer unit 130.

[0021] Through the above-described conveying process and image forming process of the sheet S, a full-color toner image is secondarily transferred onto the sheet S in the secondary transfer section 130. Thereafter, the sheet S is conveyed to the fixing device 150. The fixing device 150 applies a predetermined pressure force by rollers or belts that are substantially opposed to each other, and a heating effect by a heat source such as a heater, to melt and fix the toner on the sheet S. The sheet S having the fixed image thus obtained is guided in a first direction toward the discharge roller 161 by the switching flapper 200 located at the first position. The sheet S guided in the first direction by the switching flapper 200 is discharged to the discharge tray 170 by the discharge roller 161 provided in the discharge section 160.

[0022] In the case of double-sided printing, the switching flapper 200 is switched from the first position to the second position. Therefore, in the case of double-sided printing, the sheet S having the fixed image is guided by the switching flapper 200 located at the second position in a second direction toward the reversing roller 162, which is different from the first direction. The sheet S guided in the second direction by the switching flapper 200 is conveyed to the reversing guide 171 by the reversing roller 162. The sheet S conveyed by the reversing roller 162 while being supported by the reversing guide 171 is conveyed to the double-sided conveying path 180 by the reversing operation of the reversing roller 162 after the rear end of the sheet S passes through the reversing flapper 210. The sheet S passing through the double-sided conveying path 180 is again subjected to skew correction and timing correction by the skew correction device 120, and then sent to the secondary transfer unit 130. Then, the image of the second side is transferred onto the sheet S in the secondary transfer unit 130. Thereafter, the sheet S is conveyed again to the fixing device 150, where the images are fixed. Then, the sheet S having the fixed images on both sides is guided in the first direction by the switching flapper 200 switched to the first position, and is discharged onto the discharge tray 170 by the discharge rollers 161.

[0023] Next, a configuration of a switching flapper 200 that guides the conveyed sheet S in a first direction toward a discharge roller 161 or in a second direction different from the first direction toward a reversing roller 162 will be described with reference to Fig. 2. Fig. 2 is an external perspective view of the discharge section 160 having the switching flapper 200.

[0024] The switching flapper 200 is a switching means that can be switched to a first position where the sheet S being conveyed is guided in a first direction, or a second position where the sheet S is guided in a second direction different from the first direction. As described above, the switching flapper 200 guides the sheet S in the first direction toward the discharge roller 161 at the first position shown in Fig. 3. The switching flapper 200 guides the sheet S in the second direction toward the reversing roller 162 at the second position shown in Fig. 4.

[0025] The switching flapper 200 has a flapper shaft 202, a flapper guide 201, and a flapper link 203. The flapper shaft 202 is a shaft member extending in a width direction perpendicular to the sheet conveying direction. The flapper guide 201 is a guide member that rotates together with the flapper shaft 202 to guide the sheet S at the first position or the second position. The flapper link 203 is a transmission member that transmits a force for rotating the flapper shaft 202 to the flapper shaft 202. The flapper guide 201 and the flapper link 203 are inserted into the flapper shaft 202. The flapper shaft 202 is rotatably supported by the discharge section 160 at both ends thereof. The flapper link 203 is connected to a solenoid link 204, and the solenoid link 204 is connected to a solenoid 205 that is a drive source. When the solenoid 205 is driven in response to a signal from the main body of the apparatus, the flapper link 203 receives a force via the solenoid link 204, causing the flapper shaft 202 to rotate, and the flapper guide 201 to rotate together with the flapper shaft 202. In this manner, the switching flapper 200 is rotated to switch positions.

[0026] Although the assembly sequence of the switching flapper 200 will be described later, the flapper guide 201 is inserted into the flapper shaft 202 in an insertion direction (the direction of the arrow T1 shown in FIG. 7) from one end of the flapper shaft 202 to the other end of the flapper shaft 202. Also, the flapper link 203 is inserted in the insertion direction into one end of the flapper shaft 202 supported by a support member 163 that rotatably supports both end portions of the flapper shaft 202.

[0027] Next, switching of the position of the switching flapper 200 will be described with reference to Figures 3 and 4. Figure 3 is a cross-sectional view of the discharge section 160 when the switching flapper 200 is in the first position (standby position), and Figure 4 is a cross-sectional view of the discharge section 160 when the switching flapper 200 is in the second position (operating position).

[0028] The switching flapper 200 is in a standby position when the flapper guide 201 is in a first position where the flapper guide 201 guides the sheet S from the fixing unit 150 to the discharge rollers 161. Therefore, the sheet S that has passed through the fixing unit 150 is guided to the discharge rollers 161 by the flapper guide 201 in the first position. P1 shown in Fig. 3 indicates the sheet transport path along which the sheet S that has passed through the fixing unit 150 passes through the flapper guide 201 and reaches the discharge rollers 161. Note that the switching flapper 200 in the standby position is constantly subjected to a force by a spring member (not shown) so as to maintain the standby position.

[0029] Then, the switching flapper 200 drives the solenoid 205 in synchronization with the transport timing of the sheet S during double-sided printing, thereby moving the flapper guide 201 to a second position (operating position) for guiding the sheet S from the fixing unit 150 to the reversing roller 162. Therefore, the sheet S that has passed through the fixing unit 150 is guided to the reversing roller 162 by the flapper guide 201 in the second position. P2 shown in FIG. 4 indicates the sheet transport path along which the sheet S that has passed through the fixing unit 150 passes through the flapper guide 201 and reaches the reversing roller 162.

[0030] In this way, the flapper guide 201 of the switching flapper 200 must guide the sheet S that has passed through the fixing unit 15 in either the direction toward the discharge roller 161 (conveyance path P1) or the direction toward the reversing roller 162 (conveyance path P2). For this reason, the flapper guide 201 has two conveyance guide surfaces: a first conveyance guide surface that guides the sheet S at the first position shown in Fig. 3, and a second conveyance guide surface that guides the sheet S at the second position shown in Fig. 4. In addition, the upstream side of the flapper guide 201 in the sheet conveyance direction forms a comb shape in the width direction perpendicular to the sheet conveyance direction.

[0031] Next, the configuration of the switching flapper 200 in the sheet width direction will be described with reference to Fig. 5. Fig. 5 is a view of the switching flapper 200 as seen from a direction perpendicular to the sheet width direction.

[0032] In Fig. 5, the side that supports one end of flapper shaft 202 is the front side F of the image forming apparatus, and the side that supports the other end of flapper shaft 202 is the rear side R of the image forming apparatus. Note that flapper guide 201 and flapper link 203 are inserted into flapper shaft 202 in the insertion direction of arrow T1 shown in Fig. 7, with the front side F of the image forming apparatus being the upstream side of the insertion direction, and the rear side R being the downstream side of the insertion direction. Also, the vertically upper side of the image forming apparatus is the upper side of the image forming apparatus, and the vertically lower side is the lower side of the image forming apparatus. In this way, the front-rear and up-down directions are shown in Fig. 5.

[0033] The flapper guide 201 is disposed so as to extend into the sheet conveying area Z inside the front and rear support parts 163F, 163R of the support member 163 that supports both ends of the flapper shaft 202. At both ends of the flapper guide 201, a certain gap is provided between each of the support parts 163F, 163R of the support member 163, so that the sliding load in the rotation direction of the switching flapper 200 does not increase. That is, a certain gap is provided between the end of the front side F, which is one end of the flapper guide 201, and the support part 163F, and between the end of the rear side R, which is the other end of the flapper guide 201, and the support part 163R. The sheet conveying area Z is an area from the end of the front side F to the end of the rear side R of the flapper guide 201 in the sheet width direction. The flapper guide 201 is configured to be able to guide the sheet S throughout the entire sheet conveying area Z.

[0034] The supporting member 163 has supporting portions 163F and 163R that support both ends of the flapper shaft 202. The supporting member 163 is formed integrally with a conveying guide 164 that guides the sheet S from the fixing device 150 to the discharge rollers 161. That is, the supporting member 163 also serves as the conveying guide 164 that guides the sheet S. The flapper guide 201 is rotatably supported by the supporting member 163 as both ends of the flapper shaft 202 are rotatably supported by the supporting member 163.

[0035] Further, a flapper link 203 is disposed on the front side F of the switching flapper 200. The flapper link 203 is inserted into one end of a flapper shaft 202 that extends to the outside of the support member 163 in the sheet width direction. The reason why the flapper link 203 is disposed outside the sheet conveying area Z is because it is easy to drive and connect with a solenoid 205 disposed outside the sheet conveying area Z, and also because it does not affect the conveyability of the sheet S.

[0036] The switching flapper 200 also has a restricting portion that restricts the movement of the flapper shaft 202 in the insertion direction before the flapper guide 201 when the flapper shaft 202 receives a pressing force due to the insertion of the flapper link 203. As shown in FIG. 6, this restricting portion is an abutting portion 202b provided on the flapper shaft 202. The flapper shaft 202 has a second shaft portion 202a at the end of the rear side R, which has a smaller diameter than the first shaft portion 202c that holds the flapper guide 201 and is rotatably supported by the support portion 163R of the support member 163. The abutting portion 202b is a step portion between the first shaft portion 202c and the second shaft portion 202a. The abutting portion 202b faces the restricting surface 163b of the support member 163. Abutment portion 202b is provided between the end portion of rear side R of flapper guide 201 and support portion 163R of support member 163. Therefore, even if flapper shaft 202 receives a pressing force that moves it in the insertion direction due to the insertion of flapper link 203, abutment portion 202b of flapper shaft 202 abuts against regulating surface 163b of support member 163 before flapper guide 201 abuts against support member 163. As a result, even if flapper shaft 202 receives a pressing force due to the insertion of flapper link 203, the movement of flapper shaft 202 is restricted before the movement of flapper guide 201.

[0037] Here, the assembly sequence of the switching flapper 200 will be described with reference to Figures 7 and 8. Figure 7 is a diagram showing how the flapper shaft 202 is inserted into the flapper guide 201, and Figure 8 is a diagram showing how the flapper link 203 is inserted into the flapper shaft 202 attached to the support member 163.

[0038] In this embodiment, the flapper guide 201 and the flapper link 203 are press-fitted onto the flapper shaft 202 in an insertion direction (the direction of arrows T1 and T2) from one end of the flapper shaft 202 to the other end thereof.

[0039] As shown in FIG. 7, the flapper shaft 202 has a D-cut portion 202d having a D-cut shape at one end, and a parallel pin 206 is provided at the other end, and the flapper guide 201 is press-fitted into the flapper shaft 202 in the direction of the arrow T1. The D-cut portion 202d and the parallel pin 206 fix the phase of the flapper guide 201 in the rotation direction relative to the flapper shaft 202 at both ends, so that the flapper guide 201 can move integrally with the flapper shaft 202 when the switching flapper 200 operates. In addition, a press-fit shape is provided at the portion of the flapper guide 201 where the parallel pin 206 is fitted, so that it is not easily displaced when an external force is unintentionally applied in the sheet width direction. The flapper shaft 202 into which the flapper guide 201 is press-fitted in this way is attached to the support member 163 so as to be rotatably supported.

[0040] 8, the flapper link 203 is press-fitted into the D-cut portion 202d of the flapper shaft 202 in the direction of the arrow T2. A press-fit shape is provided at the portion of the flapper link 203 where the D-cut portion 202d is fitted. This prevents the flapper shaft 202 and the flapper link 203 from rattling in the rotation direction, and prevents deviation in the amount of rotation during operation of the solenoid 205. In addition, the flapper link 203 is snap-fitted to the flapper shaft 202 in the seat width direction, eliminating the need to provide a restricting member such as a locking member.

[0041] In the switching flapper 200 thus attached to the discharge section 160, the direction of the arrow T1 in which the flapper guide 201 is press-fitted into the flapper shaft 202 is the same as the direction of the arrow T2 in which the flapper link 203 is press-fitted into the flapper shaft 202. When the flapper link 203 is press-fitted, a pressing force acts on the flapper shaft 202 in the direction of the arrow T2, and the flapper shaft 202 tries to move together with the flapper guide 201 already press-fitted in the direction of the arrow T2. However, before the movement of the flapper guide 201 is restricted, the abutting portion 202b of the flapper shaft 202 abuts against the restricting surface 163b of the support member 163. As a result, the pressing force caused by the press-fitting of the flapper link 203 does not reach the flapper guide 201. Therefore, when attaching the switching flapper 200, the positions of the flapper guide 201 and the flapper shaft 202 do not shift relative to each other in the insertion direction due to the press-fitting of the flapper link 203.

[0042] In contrast to this, a case where the flapper shaft 202 does not have an abutting portion (regulating portion) will be described with reference to Figures 9 and 10. Figures 9 and 10 are cross-sectional views of the rear side R of a switching flapper 200 of a comparative example.

[0043] The end of the rear side R of the flapper shaft 202 in the comparative example shown in Figs. 9 and 10 is supported by the support portion 163R of the support member 163, but there is no abutting portion (regulating portion) at the end of the rear side of the flapper shaft 202, which is different from the above-mentioned embodiment. Therefore, when the flapper shaft 202 tries to move in the insertion direction, the flapper guide 201 moving together with the flapper shaft 202 hits the support member 163 and is restricted in movement. Then, the pressing force when the flapper link 203 is pressed into the flapper shaft 202 is applied to the flapper guide 201. At this time, since the flapper shaft 202 does not have a restricting portion such as the abutting portion that restricts the movement, only the flapper shaft 202 moves further in the insertion direction while the movement of the flapper guide 201 is restricted. As a result, the positions of the flapper guide 201 and the flapper shaft 202 are relatively shifted. If the axial movement of the flapper shaft 202 cannot be restricted in this way, the pressing force applied when the flapper link 203 is press-fitted into the flapper shaft 202 will act to eliminate the gap necessary for the switching flapper 200 to operate smoothly in the sheet width direction, resulting in malfunction of the switching operation of the switching flapper 200, especially when returning to the standby position due to the spring force.

[0044] In contrast, this embodiment has an abutting portion 202b that restricts the movement of the flapper shaft 202 in the insertion direction before the flapper guide 201 does, when the flapper shaft 202 receives a pressing force in the insertion direction due to the insertion of the flapper link 203. As a result, even if the flapper shaft 202 receives a pressing force that moves it in the insertion direction due to the insertion of the flapper link 203, the movement of the flapper shaft 202 is restricted before the movement of the flapper guide 201 does. Therefore, even if the flapper shaft 202 receives a pressing force due to the insertion of the flapper link 203, it is possible to ensure a gap t3 (see FIG. 6) between the flapper guide 201 and the support member 163. In addition, the position of the flapper guide 201 relative to the flapper shaft 202 is not displaced. As a result, a gap necessary for the switching flapper 200 to rotate is ensured, and malfunctions due to an increase in the load in the rotation direction of the switching flapper 200 can be prevented.

[0045] In addition, the support member 163 in this embodiment is formed integrally with the conveyance guide to the discharge roller 161, but is not limited to the conveyance guide. However, from the viewpoint of the positional accuracy of the conveyance guide surface that guides the sheet S, it is preferable that the switching flapper 200 is directly supported for rotation by the conveyance guide.

[0046] Although the parallel pin 206 is used to fix the phase of the flapper guide 201 relative to the flapper shaft 202, a spring pin or other device capable of fixing the phase in the rotation direction may be used.

[0047] Also, although the flapper link 203 is disposed on the front side of the image forming apparatus, it may be disposed on the rear side of the image forming apparatus. If a drive unit for driving a roller that conveys the sheet S is disposed on the rear side of the image forming apparatus, it becomes relatively difficult to dispose the drive section of the switching flapper 200, including the solenoid 205. For this reason, it is preferable to dispose the drive section of the switching flapper 200, including the solenoid 205, on the front side of the image forming apparatus, which is opposite to the rear side where the drive unit is disposed, in order to have more space.

[0048] Example 2 An image forming apparatus including a sheet conveying device according to the second embodiment will be described. The schematic configuration of the image forming apparatus is the same as that of the above-described embodiment, and therefore the description will be omitted here. The configuration of the regulating unit that regulates the movement of the switching flapper 200 in the sheet width direction, which is a feature of this embodiment, will be described.

[0049] In the above-described first embodiment, a configuration is described in which the movement of the switching flapper 200 in the sheet width direction is restricted by providing the abutting portion 202b (restricting portion) on the flapper shaft 202, but in this embodiment, a configuration is described in which a restricting portion is not provided on the flapper shaft 202. Fig. 11 is a cross-sectional view of the end portion on the rear side R of the switching flapper 200 according to the second embodiment.

[0050] The rear end portion of the flapper shaft 202, which is located on the downstream side in the insertion direction, is rotatably supported by the support portion 163R of the support member 163, but is not provided with an abutment portion as in the above-described embodiment 1. In this embodiment, a regulating member 300 is provided adjacent to the rear end portion of the flapper shaft 202.

[0051] The regulating member 300 is provided on the support member 163. The regulating member 300 is a regulating portion that regulates the movement of the flapper shaft 202 in the insertion direction before the flapper guide 201. In the insertion direction, the downstream end of the flapper shaft 202 abuts against the regulating member 300 before the downstream end of the flapper guide 201 in the insertion direction abuts against the support member 163.

[0052] The regulating member 300 is provided outside the area where the flapper guide 201 is arranged via the support member 163 in the insertion direction. The regulating member 300 has a regulating surface 300a against which the downstream end of the flapper shaft 202 abuts. In the insertion direction, the distance from the downstream end of the flapper guide 201 to the downstream end of the flapper shaft 202 is defined as a distance t1. In addition, in the insertion direction, the distance from the regulating surface 163b of the support member 163 facing the downstream end of the flapper guide 201 to the regulating surface 300a of the regulating member 300 against which the downstream end of the flapper shaft 202 abuts is defined as a distance t2. The regulating member 300 is provided at a position relative to the support member 163 such that the relationship of the distances is t1>t2. As a result, a gap t3 is provided between the downstream end of the flapper guide 201 and the regulating surface 163b of the support member 163 facing it, the gap being equal to the difference between the distances t1 and t2.

[0053] In this manner, since the regulating member 300 is provided adjacent to the rear end of the flapper shaft 202, the movement of the flapper shaft 202 in the sheet width direction can be regulated in the same manner as in the first embodiment. Therefore, even if a pressing force is applied when the flapper link 203 is inserted into the flapper shaft 202, the end of the flapper shaft 202 is regulated by the regulating member 300 before the movement of the flapper guide 201 in the sheet width direction is regulated. Therefore, even if the flapper shaft 202 receives a pressing force due to the insertion of the flapper link 203, the gap t3 can be secured between the flapper guide 201 and the support member 163, and the position of the flapper guide 201 with respect to the flapper shaft 202 does not shift relative to the flapper shaft 202. As a result, the gap necessary for the switching flapper 200 to rotate is secured, and malfunction due to an increase in the load in the rotation direction of the switching flapper 200 can be prevented.

[0054] In this embodiment, the regulating member 300 is configured as a separate member from the support member 163, but this is not limited to this and may be configured to be integrally formed with the support member 163 or integrally formed with another part.

[0055] Other Examples In the above-described embodiment, the image forming apparatus uses four image forming units, but the number of units used is not limited to this and may be set appropriately as required.

[0056] In the above embodiment, a printer is exemplified as an image forming apparatus, but the present invention is not limited thereto. For example, other image forming apparatuses such as a copier or a facsimile machine, or other image forming apparatuses such as a multifunction machine combining the functions of these, may be used. In addition, an image forming apparatus that uses an intermediate transfer body, transfers toner images of each color to the intermediate transfer body in a sequentially overlapping manner, and transfers the toner images carried on the intermediate transfer body to a sheet all at once is exemplified, but the present invention is not limited thereto. For example, an image forming apparatus that uses a sheet carrier, transfers toner images of each color to a sheet carried on the sheet carrier in a sequentially overlapping manner. The same effect can be obtained by applying the present invention to a sheet conveying device having a switching means used in these image forming apparatuses.

[0057] In the above embodiment, the sheet transport device is integral with the image forming apparatus, but the present invention is not limited to this. For example, the sheet transport device may be detachable from the image forming apparatus, and the same effect can be obtained by applying the present invention to the sheet transport device.

[0058] In the above-described embodiment, a sheet conveying device that conveys sheets such as recording paper as recording objects is exemplified, but the present invention is not limited to this. For example, the same effect can be obtained when applied to a sheet conveying device that conveys sheets such as documents as reading objects. [Explanation of symbols]

[0059] S...Seat 100 ... Image forming device 150... Fuser 160...Discharge section 161 ... Discharge roller 162 ... Reversing roller 163 ... Support member 163a …Regulatory aspects 163F,163R…Support part 164 ...Transport guide 170 ... Discharge tray 171 ... Reverse guide 180 ... Double-sided transport path 200 ... Switching flapper 201 ... Flapper Guide 202 ... Flapper shaft 202a ... second shaft portion 202b…Abutting section 202c ... first shaft part 202d …D-cut section 203 ... Flapper Link 204 ... Solenoid link 205 ... Solenoid 206 ... Parallel pin 210 ... Inverted flapper 300 ... Regulatory material 300a …Regulatory aspects

Claims

1. A sheet conveying device having a switching means that can be switched between a first position for guiding a conveyed sheet in a first direction and a second position for guiding a conveyed sheet in a second direction different from the first direction, The switching means is a shaft member extending in a width direction perpendicular to a conveying direction of the sheet; a guide member that is inserted into the shaft member in an insertion direction from one end of the shaft member to the other end of the shaft member and rotates together with the shaft member to guide the sheet at the first position or the second position; a transmission member that is inserted in the insertion direction into one end of the shaft member supported by a support member that rotatably supports both ends of the shaft member, and transmits a force that rotates the shaft member to the shaft member; a restricting portion that restricts movement of the shaft member in the insertion direction before the guide member abuts against the support member when the shaft member receives a pressing force in the insertion direction due to the insertion of the transmission member, A sheet conveying device comprising:

2. the restricting portion is an abutting portion that is provided on the shaft member and abuts against the support member before a downstream end of the guide member in the insertion direction abuts against the support member.

2. The sheet transport device according to claim 1.

3. The abutting portion is provided between an end portion of the shaft member on a downstream side in the insertion direction of the guide member and the support member.

3. The sheet transport device according to claim 2.

4. the shaft member has a second shaft portion at a downstream end in the insertion direction, the second shaft portion having a smaller diameter than the first shaft portion that holds the guide member and is rotatably supported by the support member; The abutment portion is a step portion between the first shaft portion and the second shaft portion.

4. The sheet transport device according to claim 2, wherein the sheet transport device is a sheet conveying device.

5. the restricting portion is provided on the support member, and a downstream end of the shaft member in the insertion direction abuts against the restricting portion before a downstream end of the guide member in the insertion direction abuts against the support member, thereby restricting movement of the shaft member in the insertion direction.

2. The sheet transport device according to claim 1.

6. The restricting portion has a restricting surface against which the shaft member abuts, the regulating portion is provided outside an area in which the guide member is disposed via the support member in the insertion direction, and is provided at a position such that, when a distance from a downstream end of the guide member to a downstream end of the shaft member is t1 and a distance from a regulating surface of the support member facing the downstream end of the guide member to a regulating surface of the regulating portion against which the downstream end of the shaft member abuts is t2, the relationship of the distances is t1>t2.

6. The sheet transport device according to claim 5,

7. The guide member and the transmission member are press-fitted into the shaft member in the insertion direction.

7. The sheet transport device according to claim 1, wherein the sheet transport device is a sheet conveying device.

8. The support member also serves as a conveying guide for guiding a sheet.

8. The sheet transport device according to claim 1, wherein the sheet transport device is a sheet conveying device.

9. 9. An image forming apparatus having an image forming section for forming an image on a sheet and a sheet transport section for transporting the sheet, the image forming apparatus comprising the sheet transport device according to claim 1 as the sheet transport section.

1. An image forming apparatus comprising:

Images