Sheet conveying apparatus, sheet processing apparatus, and image forming apparatus

Abstract

To provide a sheet conveying device capable of suppressing skewing of a sheet, a sheet processing device, and an image forming apparatus.SOLUTION: The sheet conveying device includes a pair of shift rollers 13 movable in the width direction orthogonal to the sheet conveying direction, and a shift means for performing shift operation for shifting the sheet in the width direction by moving the pair of shift rollers 13 in the width direction when conveying the sheet by the pair of shift rollers 13. A shift driven roller 13b which is one shift roller of a pair of shift rollers includes driven roller shafts 131b1, 131b2 which are a plurality of roller shafts, and a connection member 30 which connects the roller shafts to each other and is swingable with respect to the roller shafts.SELECTED DRAWING: Figure 23

Description

[Technical Field]

[0001] The present invention relates to a sheet conveying device, a sheet processing device, and an image forming apparatus. [Background technology]

[0002] 2. Description of the Related Art Conventionally, a sheet conveying device including a pair of conveying rollers for conveying a sheet is known.

[0003] Patent document 1 describes a device that includes a pair of shift rollers that can move in the width direction, which is a direction perpendicular to the sheet conveying direction, and a shift means that performs a shift operation to move the pair of shift rollers in the width direction and shift the sheet in the width direction when the sheet is conveyed by the shift roller pair. Summary of the Invention [Problem to be solved by the invention]

[0004] However, there is a risk that the sheet may become skewed. [Means for solving the problem]

[0005] In order to solve the above-mentioned problems, the present invention provides a sheet conveying device having a pair of conveying rollers for conveying a sheet, wherein the pair of conveying rollers is a pair of shift rollers that can move in a width direction that is perpendicular to the sheet conveying direction, and the device is equipped with a shift means that performs a shift operation to move the pair of shift rollers in the width direction when the sheet is conveyed by the pair of shift rollers, thereby shifting the sheet in the width direction, and one of the pair of shift rollers has a plurality of roller shafts and a connecting member that connects the roller shafts to each other and is capable of swinging relative to the roller shafts. [Effects of the Invention]

[0006] According to the present invention, it is possible to suppress skew of the sheet. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is an explanatory diagram illustrating an example of the configuration of an image forming system. [Figure 2] FIG. 1 is a functional block diagram of an image forming system. [Figure 3] FIG. 1 is a functional block diagram of an image forming system. [Figure 4] FIG. 2 is a hardware configuration diagram of an electrical component of the image forming system. [Figure 5] FIG. 4 is an explanatory diagram of a conveying path of the inner finisher. [Figure 6] FIG. 10 is an explanatory diagram of the operation of the inner finisher. [Figure 7] FIG. 10 is an explanatory diagram of the operation of the inner finisher. [Figure 8] FIG. 10 is an explanatory diagram of the operation of the inner finisher. [Figure 9] FIG. 10 is an explanatory diagram of the operation of the inner finisher. [Figure 10] FIG. 3 is a schematic diagram of a pair of shift rollers according to the embodiment. [Figure 11] FIG. 4 is a plan view of a pair of shift rollers according to the embodiment. [Figure 12] FIG. 10 is a schematic diagram showing a state in which the shift roller pair is shifted by the shift mechanism. [Figure 13] 10 is a schematic diagram of a conventional shift roller pair. [Figure 14] 10 is a graph showing the pressure applied to a sheet by each conveying roller pair in a conventional shift roller pair. [Figure 15] FIG. 10 is a diagram showing an example of paper transport using a conventional shift roller pair. [Figure 16] FIG. 10 is a diagram showing another example of paper transport using a conventional shift roller pair. [Figure 17] (a) is a schematic diagram showing a conventional shift roller pair shifted to the rear side, and (b) is a graph showing the pressure applied to the paper by each conveying roller pair when the conventional shift roller pair is shifted to the rear side. [Figure 18] (a) is a schematic diagram showing a conventional shift roller pair shifted toward the front, and (b) is a graph showing the pressure applied to the paper by each conveying roller pair when the conventional shift roller pair is shifted toward the front. [Figure 19] 1A is a diagram showing a state when the shift roller pairs of this embodiment are positioned at default positions, and FIG. 1B is a graph showing the pressure applied to the paper by each conveying roller pair at that position. [Figure 20] 5A and 5B are diagrams illustrating an example of paper transport by a pair of shift rollers according to the embodiment. [Figure 21] 10A and 10B are diagrams illustrating another example of paper transport by the shift roller pair of the present embodiment. [Figure 22] 10 is a diagram showing an example of a configuration in which the swing of the connecting member 30 is not restricted during a shift operation. FIG. [Figure 23] 10 is a schematic diagram of a shift driven roller in which a first driven roller shaft and a second driven roller shaft are connected by a connecting member of the embodiment. FIG. [Figure 24] 5A and 5B are diagrams illustrating the dimensional relationship between a connecting member and a driven roller shaft according to the embodiment. [Figure 25] FIG. 10A is a diagram illustrating the swing regulation of the connecting member when the shift roller pair is shifted toward the rear, and FIG. 10B is a diagram illustrating the swing regulation of the connecting member when the shift roller pair is shifted toward the front. [Figure 26] (a) is a schematic diagram showing the state in which the shift roller pair of this embodiment is shifted toward the rear, and (b) is a graph showing the pressure applied to the paper by each conveying roller pair when the shift roller pair of this embodiment is shifted toward the rear. [Figure 27] (a) is a schematic diagram showing the state in which the shift roller pair of this embodiment is shifted toward the front, and (b) is a graph showing the pressure applied to the paper by each conveying roller pair when the shift roller pair of this embodiment is shifted toward the front. [Figure 28] FIG. [Figure 29] FIG. 10 is a diagram illustrating the dimensional relationship of a first modified example. [Figure 30] FIG. 10A is a diagram illustrating the swing regulation of the connecting member when the shift roller pair is shifted toward the rear in the first modified example, and FIG. 10B is a diagram illustrating the swing regulation of the connecting member when the shift roller pair is shifted toward the front in the first modified example. [Figure 31] FIG. [Figure 32] FIG. 10 is a diagram illustrating the dimensional relationship of a second modified example. [Figure 33] 10A is a diagram illustrating the swing regulation of the connecting member when the shift roller pair is shifted toward the rear in the second modified example, and FIG. 10B is a diagram illustrating the swing regulation of the connecting member when the shift roller pair is shifted toward the front in the second modified example. [Figure 34] (a) is a schematic diagram showing an example in which a connecting member is placed between the rear pair of conveying rollers and the second pair of conveying rollers from the rear, and (b) is a graph showing the pressure applied to the paper by each pair of conveying rollers in that example. [Figure 35] (a) is a schematic diagram showing an example in which a connecting member is placed between the front pair of conveying rollers and the second pair of conveying rollers from the front, and (b) is a graph showing the pressure applied to the paper by each pair of conveying rollers in that example. [Figure 36] 10A is a schematic diagram showing an example in which the shift driven roller is configured with three driven roller shafts, and FIG. 10B is a graph showing the pressure applied to the paper by each conveying roller pair in this example. DETAILED DESCRIPTION OF THE INVENTION

[0008] An embodiment in which the present invention is applied to an image forming system comprising an image forming apparatus and a post-processing device will be described. First, an overview of the image forming apparatus system will be described. FIG. 1 is an explanatory diagram of an example configuration of an image forming system 1 comprising an inner finisher 100, which is a post-processing device, and an image forming apparatus 300. The inner finisher 100 is a post-processing device that is placed inside the body of the image forming apparatus to avoid an increase in installation area. The present invention can also be applied to a connection mode with a post-processing device that is placed outside the image forming apparatus 300. FIG. 1(a) shows an example configuration of an image forming system 1 in which the image forming apparatus 300 and the inner finisher 100 are connected. Paper (sheets) on which images have been formed from the image forming apparatus 300 are received by the inner finisher 100 and post-processing such as binding is performed.

[0009] 1(b) shows an example of the configuration of an image forming system 1 in which an image forming apparatus 300, an inner finisher option device 200, and an inner finisher 100 are connected. Paper sheets on which images have been formed from the image forming apparatus 300 are subjected to punching and other processes by the inner finisher option device 200, and are then received by the inner finisher 100, where post-processing such as binding is performed. The inner finisher option device 200 is an optional device that the user can purchase and choose whether or not to install.

[0010] Instead of or in addition to the inner finisher option device 200 that performs punching and other processes, it is also possible to connect an inner finisher option device 400 that performs folding and other processes. The inner finisher option device 200 and the inner finisher option device 400 are optional and therefore detachable, and the I / F parts of the optional devices are configured to be detachable in hardware, for example, by using a relay connector or a drawer connector.

[0011] 2 and 3 are functional block diagrams of the image forming system 1. FIG. 2 is a functional block diagram of the image forming system 1 without the inner finisher option. The flow of paper is indicated by dashed lines, and the flow of communication signals is indicated by solid lines. The image forming device 300 is a device that forms images on paper using a known electrophotographic process. This image forming device 300 is equipped with a display unit 301 that notifies the user of the status of various devices and operation details, and an operation unit 302 that the user uses to set the mode, number of copies, etc. The image forming device 300 also has a paper feed unit 303 that stocks paper and separates and feeds it one sheet at a time, and an image creation unit 304 that forms a latent image on a photosensitive drum and transfers the image to paper. The image forming device 300 also has a fixing unit 305 that fixes the image transferred to paper, and a control unit 306 that controls each of these blocks.

[0012] The inner finisher 100 receives processing instructions from the control unit 306 of the image forming apparatus 300 via a communication line 307 to the inner finisher control unit 102, and the inner finisher processing unit 101 performs the specified processing on the specified paper. The linked control units (306, 102) are connected by a communication line (307) to enable the exchange of information. This allows the exchange of information on the mode, paper size, timing, etc., enabling system operation.

[0013] 3 is a functional block diagram of the image forming system 1 when options are installed. The inner finisher option device 200 receives processing instructions from the inner finisher control unit 102 via the communication line 103 to the control unit 202, and performs the specified processing on the specified paper in the inner finisher option device processing unit 201. Other points are the same as those in the functional block diagram of FIG. 2.

[0014] 4 is a hardware configuration diagram of the electrical equipment of the image forming system 1. As shown in the figure, the inner finisher 100 is equipped with a CPU 110 and is connected to various motors and various sensors via an I / F (interface). The CPU 110 is a computing means and controls the overall operation of the inner finisher 100.

[0015] The various motors include a transport motor 111, a paper discharge motor 112, a jogger drive motor 113, a staple drive motor 114, and a shift motor 25. The various sensors include a transport sensor 115, a paper discharge sensor 116, and a staple movement home position sensor 117.

[0016] The inner finisher option device 200 and the inner finisher option device 400, which are optional devices of the inner finisher 100, are connected to the CPU 110 of the inner finisher 100 via an I / F. The operations of the inner finisher option device 200 and the inner finisher option device 400 are controlled by the CPU 110 of the inner finisher 100.

[0017] The inner finisher option device 200 includes a punch motor 210, a punch movement motor 211, a pre-punch sensor 212, a cover open / close sensor 213, and a punch unit home position sensor 214. The inner finisher option device 400 includes a folding motor 410, an entrance sensor 411, and a folding sensor 412.

[0018] The CPU 110 in the inner finisher 100 is connected to the control unit 306 of the image forming apparatus 300 via an I / F, and controls the inner finisher 100 in response to processing signals from the image forming apparatus 300. Since the inner finisher 100 is also an optional device, it has a detachable hardware configuration similar to the inner finisher optional device 200 and the inner finisher optional device 400.

[0019] FIG. 5 is an explanatory diagram of the transport path of the inner finisher 100. The entrance roller pair 11 is the most upstream transport roller pair of the inner finisher, the transport roller pair 12 is the second transport roller pair of the inner finisher, and the shift roller pair 13 is a transport roller pair that shifts paper in the width direction within the inner finisher. The return roller 14 transports and strikes paper toward the reference fence 18, the striking roller 15 transports paper toward the reference fence 18, and the discharge roller 16a is the most downstream transport roller of the inner finisher. The staple tray 17 is a tray that temporarily stacks paper for binding and corresponds to a sheet placement unit. The reference fence 18 is a fence that strikes the trailing edge of paper during binding and aligns the transport direction, and corresponds to a stop member. The stapler 19 is a device that performs the binding process. The discharge tray 20 is a tray that discharges paper and can also discharge a stack of paper after binding. The end fence 21 is a fence against which the trailing edge of the discharged paper is abutted and aligned.

[0020] The inner finisher 100 has a mode (shift discharge mode) in which the paper is transported and discharged directly to the discharge tray 20, and a mode (staple mode) in which the paper is stapled by a stapler 19. In the shift discharge mode, the paper transported from the image forming device 300 is received by the pair of entrance rollers 11, transported to the discharge rollers 16a, and discharged to the discharge tray 20.

[0021] In the staple mode, the paper conveyed from the image forming device 300 is received by the pair of inlet rollers 11, conveyed to the pair of shift rollers 13, and then switchback-conveyed on the staple tray 17 by the striking rollers 15 and return rollers 14, and the paper is conveyed to the reference fence 18. This operation is repeated a predetermined number of times, and when the last sheet has been conveyed to the reference fence 18, the stapler 19 staples the stack of paper to bind it, and the stack of paper is discharged by the return rollers 14 and the paper discharge rollers 16a to the paper discharge tray 20.

[0022] 6 to 9 are explanatory diagrams of the movement of paper P in shift discharge mode. In FIG. 6, paper P transported from the image forming apparatus 300 is received into the inner finisher 100 and transported. In FIG. 7, the shift roller pair 13 is moved in the width direction of the paper, and the paper P is transported while being shifted in the width direction by the shift roller pair 13. In FIG. 7, the paper discharge driven roller 16b remains in the pressure release position. In FIG. 8, after paper P passes through the shift roller pair 13, the paper discharge driven roller 16b moves from the pressure release position to the nip position, and the paper P is discharged onto the paper discharge tray 20 by the paper discharge roller 16a. In FIG. 9, paper P is discharged onto the paper discharge tray 20.

[0023] FIG. 10 is a schematic diagram of the shift roller pair 13 of this embodiment as viewed from the downstream side in the sheet conveying direction, and FIG. 11 is a plan view of the shift roller pair 13 of this embodiment. The shift roller pair 13 has a shift drive roller 13a and a shift driven roller 13b. The shift drive roller 13a has a drive roller shaft 131a and four drive conveying rollers 140a supported by the drive roller shaft 131a. The four drive conveying rollers 140a are supported by the drive roller shaft 131a at predetermined intervals in the axial direction (width direction of the paper P) so as to rotate integrally with the drive roller shaft 131a. The drive roller shaft 131a is supported by the rear side plate 34a and front side plate 34b of the inner finisher 100 via bearings 35 so as to be rotatable and movable in the axial direction (width direction of the paper P).

[0024] The shift driven roller 13b has a first driven roller shaft 131b1 and a second driven roller shaft 131b2, which are connected at the center in the axial direction by a connecting member 30. Each of the driven roller shafts 131b1 and 131b2 has two driven conveying rollers 140b provided at a predetermined interval in the axial direction. The multiple driven conveying rollers 140b are press-fitted and fixed to the driven roller shafts 131b1 and 131b2 and supported by the driven roller shafts 131b1 and 131b2 so as to rotate integrally with the driven roller shafts 131b1 and 131b2. Each driven conveying roller 140b comes into contact with a corresponding driving conveying roller 140a of the shift driving roller 13a, forming four conveying roller pairs 40a, 40b, 40c, and 40d.

[0025] Furthermore, the two driven conveying rollers 140b supported on the first driven roller shaft 131b1 and the two driven conveying rollers 140b supported on the second driven roller shaft 131b2 are biased toward the shift drive roller by pressure members 32a and 32b. Each pressure member 32a and 32b is a spring, and one end is fixed to pressure fixing members 33a and 33b, and the other end is fixed to pressure receiving members 31a and 31b. Each pressure receiving member 31a and 31b abuts against the outer circumferential surface of the driven roller shaft 131b1 and 131b2.

[0026] On the front side of the inner finisher 100, a shift mechanism 60 is provided as a shift means for moving the shift roller pair 13 in the axial direction (width direction of the paper P). Shift mechanism 60 includes shift motor 25. A pulley is provided at the tip of the motor shaft of shift motor 25, and timing belt 26 is stretched between the pulley of shift motor 25 and another pulley disposed a predetermined distance apart in the axial direction from the pulley. Movable member 27 is fixed to timing belt 26.

[0027] The movable member 27 has a first through hole 27a through which the drive roller shaft 131a passes and a second through hole 27b through which the first driven roller shaft 131b1 passes. The diameter of the first through hole 27a is longer than the diameter of the drive roller shaft 131a, allowing the drive roller shaft 131a to rotate freely relative to the movable member 27. The second through hole 27b is elongated in the vertical direction (a direction perpendicular to both the paper conveyance direction and the paper width direction). The length of the second through hole 27b in the short direction is longer than the diameter of the first driven roller shaft 131b1, allowing the first driven roller shaft 131b1 to rotate freely relative to the movable member 27. Grooves are formed on both sides of the drive roller shaft 131a and the first driven roller shaft 131b1 with the movable member 27 interposed therebetween, and regulating members 28 are fitted into these grooves.

[0028] An output gear 29 is attached to the front end of the drive roller shaft 131a so as to rotate integrally with the drive roller shaft 131a. The output gear 29 meshes with a wide gear 61 of a drive transmission device that transmits the driving force of the conveyance motor 111 to the shift drive roller 13a. The wide gear 61 is longer in the axial direction than the output gear 29, so that meshing with the output gear 29 can be maintained even if the shift drive roller 13a moves in the axial direction.

[0029] FIG. 12 is a schematic diagram showing a state in which the shift roller pair 13 is shifted by the shift mechanism 60. As shown in FIG. When shift motor 25 is driven, timing belt 26 is driven to rotate, and movable member 27, which is fixed to timing belt 26, moves toward the rear side as shown by arrow A in the figure. As movable member 27 moves, movable member 27 comes into contact with rear-side regulating member 28 and moves toward the rear side together with rear-side regulating member 28. Then, rear-side regulating member 28 hits the side surface of the groove into which rear-side regulating member 28 is fitted, pushing first driven roller shaft 131b1 toward the rear side, and shifting shift driven roller 13b toward the rear side (arrow B1 in the figure). Similarly, the movement of movable member 27 pushes drive roller shaft 131a toward the rear side via rear-side regulating member 28, and shifting shift drive roller 13a toward the rear side (arrow B2 in the figure). By rotating the shift motor 25 in the opposite direction to the above, the movable member 27 pushes the first driven roller shaft 131b1 and the driving roller shaft 131a toward the front side via the front-side regulating member 28, and the shift roller pair 13 shifts toward the front side.

[0030] FIG. 13 is a schematic diagram of a conventional shift roller pair 13. As shown in FIG. 13, the conventional shift roller pair 13 is made up of one driven roller shaft 131b. The drive roller shaft 131a of the shift drive roller 13a, which is supported on both sides by the rear side plate 34a and the front side plate 34b via bearings 35, is bent so that the center of the axial direction is separated from the shift driven roller as shown by the solid line in the figure due to pressure from the shift driven roller 13b.

[0031] The driven roller shaft 131b of the shift driven roller 13b attempts to bend from the state shown by the dashed line in the figure to follow the bending of the drive roller shaft 131a due to the pressure applied by the pressure members 32a and 32b on the rear and front sides. However, because the driven roller shaft 131b is configured to be movable within a predetermined range in the pressure direction (up and down) of the pressure members 32a and 32b, it does not bend in the same way as the drive roller shaft 131a, and the amount of bending is smaller than that of the drive roller shaft 131a. As a result, as shown in Figure 14, the pressure applied to the paper P by the two conveyor roller pairs 40b and 40c at the center in the axial direction becomes weaker than the pressure applied by the conveyor roller pairs 40a and 40d at the end sides in the axial direction.

[0032] As shown in Fig. 13, when paper P is transported by four transport roller pairs 40a, 40b, 40c, and 40d, the paper P can be transported smoothly. However, as shown in Fig. 15, if paper P is transported toward the rear and sandwiched between transport roller pairs 40a, 40b, and 40c, transport roller pairs 40b and 40c, which apply weak pressure to paper P, may slip relative to paper P, causing the paper to skew. Also, as shown in Fig. 16, in the case of narrow paper transported by transport roller pairs 40b and 40c, which apply weak contact pressure, slippage may prevent the paper from being discharged by the specified time, resulting in a paper jam or skew.

[0033] FIG. 17(a) is a schematic diagram of the conventional shift roller pair 13 when it is shifted to the rear side, and FIG. 17(b) is a graph showing the pressure applied to the paper by each conveying roller pair at that time. As shown in FIG. 17(a), when the shift roller pair 13 is shifted toward the rear, the first transport roller pair 40a from the rear moves away from the rear pressure member 32a, and the second transport roller pair 40b from the rear moves closer to the rear pressure member 32a. The third transport roller pair 40c from the rear moves away from the front pressure member 32b, and the fourth transport roller pair 40d from the rear moves closer to the front pressure member 32b. As a result, the pressure applied to the paper by each transport roller becomes as shown in FIG. 17(b). Therefore, slippage of the paper P may occur between the transport roller pairs 40a, 40b, and 40c, and skew may occur even when the paper P is being transported by the four transport roller pairs 40a, 40b, 40c, and 40d.

[0034] FIG. 18(a) is a schematic diagram of the conventional shift roller pair 13 when it is shifted forward, and FIG. 18(b) is a graph showing the contact pressure of each conveying roller pair at that time. As shown in FIG. 18(a), when the shift roller pair 13 is shifted toward the front, the first transport roller pair 40a from the rear approaches the pressure member 32a on the rear side, and the second transport roller pair 40b from the rear moves away from the pressure member 32a on the rear side. The third transport roller pair 40c from the rear moves toward the pressure member 32b on the front side, and the fourth transport roller pair 40d from the rear moves away from the pressure member 32b on the front side. As a result, the pressure applied to the paper by each transport roller becomes as shown in FIG. 18(b). Therefore, when the shift roller pair 13 is shifted toward the front side, slippage of the paper P may occur between the transport roller pairs 40b, 40c, and 40d. Therefore, even when the paper P is being transported by the four transport roller pairs 40a, 40b, 40c, and 40d, skew may occur.

[0035] FIG. 19 is a diagram illustrating the shift roller pair 13 of this embodiment. The shift driven roller 13b of this embodiment has a first driven roller shaft 131b1 and a second driven roller shaft 131b2, and these driven roller shafts 131b1 and 131b2 are connected at the axial center by a connecting member 30. The connecting member 30 is configured to be able to swing relative to the driven roller shafts 131b1 and 131b2. With this configuration, when the drive roller shaft 131a is deflected from the dashed line to the solid line as shown in FIG. 19(a), the driven roller shafts 131b1 and 131b2 tilt relative to the connecting member 30. This allows the first driven roller shaft 131b1 and the second driven roller shaft 131b2 to follow the drive roller shaft 131a, and as shown in FIG. 19(b), it is possible to suppress a decrease in the pressure applied to the paper P by the conveying roller pair 40b and 40c at the axial center. As a result, slippage of the pair of conveying rollers 40b, 40c at the center in the axial direction with respect to the paper can be suppressed.

[0036] Therefore, as shown in Fig. 20, the occurrence of skew when the paper P is transported by the transport roller pairs 40a, 40b, and 40c at the rear side can be suppressed. Also, because slippage of the paper by the transport roller pair 40b and 40c at the center in the axial direction is suppressed, as shown in Fig. 21, when the paper is transported only by the transport roller pair 40b and 40c, the occurrence of paper jams and skew can be suppressed.

[0037] In this embodiment, the multiple driven conveying rollers 140b are press-fitted and fixed to the driven roller shaft, and the driven roller shaft is a rotating shaft that rotates integrally with the driven conveying rollers 140b, but the driven roller shaft may also be a fixed shaft, and the driven conveying rollers 140b may be configured to be rotatable relative to the driven roller shaft.

[0038] FIG. 22 is a diagram showing an example of a configuration in which the swinging of the connecting member 30 is not restricted during a shift operation. As shown in Figure 22(a), each driven roller shaft 131b1, 131b2 is rotatably connected to a connecting member 230 with connecting pins 231a, 231b as fulcrums, and the connecting member 230 can swing up and down in the figure, but cannot move in the paper transport direction (perpendicular to the paper surface).

[0039] As shown in FIG. 22(b), during the shift operation, the shift mechanism 60 moves the first driven roller shaft 131b1 toward the rear (in the direction of the arrow X1 in the figure). This movement of the first driven roller shaft 131b1 pushes the connecting member 30 diagonally downward to the left in the figure. This pushing causes the connecting member 30 to swing in the direction of the arrow X2 in the figure against the biasing force of the pressure member 32a, and the connecting portion of the second driven roller shaft 131b2 with the connecting member 30 moves in a direction away from the shift drive roller 13a (in the direction of the arrow X3 in the figure). As a result, the driven conveying roller 140b supported by the second driven roller shaft 131b2 moves away from the paper P or the pressure force on the paper P decreases, which may cause slippage of the paper between the conveying roller pair 40a, 40b and increase the skew.

[0040] Therefore, in this embodiment, each of the driven roller shafts 131b1 and 131b2 is provided with a restricting portion that abuts against the connecting member 30 during a shift operation and restricts the swinging of the connecting member. The characteristic features of this embodiment will be specifically described below.

[0041] FIG. 23 is a schematic diagram of a shift driven roller 13b in which a first driven roller shaft 131b1 and a second driven roller shaft 131b2 are connected by a connecting member 30 of this embodiment. The connecting member 30 of this embodiment has a cylindrical shape with a hole 38 passing through it in the axial direction, with a portion cut out, giving it a C-shaped cross section. Engagement protrusions 36a and 36b that protrude inward are provided at both axial ends of the connecting member 30. Grooves 132a and 132b are formed at the rear end of the first driven roller shaft 131b1 and the front end of the second driven roller shaft 131b2, respectively. The engagement protrusions 36a and 36b of the connecting member 30 are engaged with the grooves 132a and 132b of these driven roller shafts.

[0042] The engagement projections 36a, 36b of the connecting member 30 engage with the grooves 132a, 132b of these driven roller shafts, thereby preventing the driven roller shafts 131b1, 131b2 from slipping out of the connecting member 30 in the axial direction.

[0043] 24(a) is a cross-sectional view taken along line DD of FIG. 23(a), and FIG. 24(b) is an enlarged view of the periphery of the connecting member 30 of FIG. 23(a). 24(a), when the width of the notch 37 of the connecting member 30 is C, the diameter of the bottom surface of the groove 132b of the driven roller shaft is B, and the diameter of the top of the engaging protrusion 36b is A, the relationship is A>B>C. The same dimensional relationship exists between the engaging protrusion 36a on the near side, the groove 132a, and the notch 37.

[0044] 24(b), when the width (axial length) of the groove 132b is D and the width (axial length) of the engaging protrusion 36b is E, the relationship is D>E. Furthermore, when the inner diameter of the hole 38 of the connecting member 30 is F and the diameter of each of the driven roller shafts 131b1 and 131b2 is G, the relationship is F>G.

[0045] Assuming the above relationships of A>B, D>E, and F>G, each of the driven roller shafts 131b1 and 131b2 has a predetermined gap in the axial direction and radial direction relative to the connecting member 30. This allows the connecting member 30 to swing relative to each of the driven roller shafts 131b1 and 131b2 within a predetermined range. As each of the driven roller shafts 131b1 and 131b2 has a predetermined gap in the radial direction relative to the connecting member 30, each of the driven rollers 131b1 and 131b2 can rotate smoothly together with the driven conveying rollers. The relationships A>B, D>E, and F>G may be set appropriately depending on the amount of deflection of the drive roller shaft 131a. In this embodiment, if the driven roller shafts 131b1 and 131b2 can be tilted at an angle of more than 0° and not more than 5° relative to the connecting member 30, the driven roller shafts 131b1 and 131b2 can follow the deflected drive roller shaft 131a. The relationship between A and B, the relationship between D and E, and the relationship between F and G are set so that the angle θ can be tilted at 0<θ≦5°.

[0046] Furthermore, since the relationship B>C is satisfied, the driven roller shafts 131b1 and 131b2 are prevented from easily coming out of the cutout portions 37 after being connected to the connecting member 30.

[0047] The connecting member 30 of this embodiment is elastically deformable so that the width of the cutout portion 37 expands, and when connecting the driven roller shafts 131b1 and 131b2 to the connecting member 30, the ends of the driven roller shafts are pushed through the cutout portion 37 of the connecting member 30. This causes the connecting member 30 to elastically deform so that the width of the cutout portion 37 expands, and the ends of the driven roller shafts 131b1 and 131b2 are pushed into the hole portion 38 of the connecting member 30, connecting the driven roller shafts 131b1 and 131b2 to the connecting member 30. In this way, simply by pushing the ends of the driven roller shafts 131b1 and 131b2 through the cutout portion 37, the driven roller shafts 131b1 and 131b2 can be assembled into the hole portion 38 of the connecting member 30, and the shift driven roller 13b can be easily assembled. Furthermore, in this embodiment, the connecting member 30 is configured as a single member, which makes it possible to suppress an increase in the number of components of the shift driven roller 13b and suppress an increase in the cost of the device.

[0048] By setting the difference (BC) between the diameter B of the bottom surface of the groove portions 132a, 132b and the width C of the cutout portion 37 to at least 0.3 to several mm (approximately 0.5 mm in this embodiment), easy assembly can be achieved while preventing each driven roller shaft 131b1, 131b2 from coming out of the cutout portion 37. Furthermore, by making the difference between the diameter G of the driven roller shafts 131b1, 131b2 and the diameter A of the top of the engaging protrusion 36b at least a few mm (approximately 1 mm in this embodiment), it is possible to prevent each driven roller shaft 131b1, 131b2 from slipping out of the connecting member 30 in the axial direction.

[0049] In this embodiment, to ensure that the driven rollers 131b1 and 131b2 rotate smoothly together with the driven conveying rollers, the driven roller shafts 131b1 and 131b2 have a predetermined radial gap with respect to the connecting member 30. However, if the driven roller shafts 131b1 and 131b2 are fixed shafts and the driven conveying rollers rotate relative to the driven roller shafts, there does not need to be a gap in the paper conveying direction. By eliminating the gap in the paper conveying direction between the driven roller shafts 131b1 and 131b2 and the connecting member 30, it is possible to prevent the driven roller shafts 131b1 and 131b2 from tilting in the paper conveying direction relative to the connecting member 30. This prevents misalignment of the driven conveying roller 140b in the paper conveying direction and reduces the reduction in the pressure applied by the conveying roller pair to the paper.

[0050] FIG. 25(a) is a diagram illustrating the case where the shift driven roller 13b is shifted to the rear side, and FIG. 25(b) is a diagram illustrating the case where the shift driven roller 13b is shifted to the front side. As shown in FIG. 25(a), when the shift mechanism 60 moves the first driven roller shaft 131b1 toward the rear, the engagement protrusion 36a at the front end of the connecting member 30 abuts against the front side surface of the groove 132a of the first driven roller shaft 131b1 (W1 in the figure). This restricts the clockwise swing of the connecting member 30 in the figure. Then, the front side surface of the groove 132a presses the engagement protrusion 36a at the front end of the connecting member 30 diagonally downward to the left in the figure. This pressing causes the connecting member 30 to move toward the rear, as indicated by the arrow in the figure. Then, the engagement protrusion 36b at the rear end of the connecting member 30 abuts against the rear side surface of the groove 132b of the second driven roller shaft 131b2 (W2 in the figure), and the second driven roller shaft 131b2 is pressed toward the rear. 25(a) while moving toward the rear. Therefore, when shifting toward the rear, the driven roller shafts 131b1 and 131b2 can be maintained in a state of following the driving roller shaft 131a.

[0051] 25(b), when the shift mechanism 60 moves the first driven roller shaft 131b1 toward the front side, the engagement protrusion 36a at the front end of the connecting member 30 abuts against the rear side surface of the groove 132a of the first driven roller shaft 131b1 (W3 in the figure). Then, the rear side surface of the groove 132a presses the engagement protrusion 36a of the connecting member 30 diagonally upward to the right in the figure. When this pressing causes the connecting member 30 to rotate counterclockwise in the figure, the engagement protrusion 36b at the rear end of the connecting member 30 abuts against the front side surface of the groove 132b of the second driven roller shaft 131b2 (W4 in the figure), and the swinging of the connecting member 30 is restricted. This prevents the rear end of the first driven roller shaft 131b1 from moving in a direction away from the shift drive roller 13a due to the counterclockwise rotation of the connecting member 30 in the figure, and the first driven roller shaft 131b1 moves toward the front while roughly maintaining the posture shown in Figure 25(b).

[0052] 25(b) is pushed forward by the engaging projection 36b at the rear end of the connecting member 30, the front side surface of the groove 132b of the second driven roller shaft 131b2 is pushed forward, so that the second driven roller shaft 131b2 moves toward the rear while substantially maintaining the posture shown in FIG. 25(b). Therefore, when shifting toward the front side, the driven roller shafts 131b1 and 131b2 can be maintained in a state of following the driving roller shaft 131a.

[0053] In this manner, in this embodiment, the side surfaces of the grooves 132a and 32b function as restricting portions that restrict the swinging of the connecting member 30 during a shift operation.

[0054] FIG. 26(a) is a schematic diagram of the shift roller pair 13 of this embodiment when it is shifted to the rear side, and FIG. 26(b) is a graph showing the pressure applied to the paper by each conveying roller pair at that time. When the shift roller pair 13 is shifted toward the rear, the swinging of the connecting member 30 is restricted by the side surfaces of the grooves 132a and 132b, which act as restricting portions. Therefore, the postures of the first driven roller shaft 131b1 and the second driven roller shaft 131b2 hardly change, and they can maintain a state following the drive roller shaft 131a. Therefore, as shown in FIG. 26(b), the pressure applied to the paper by each of the conveying roller pairs 40a-40d can be maintained. This prevents slippage of the paper at each of the conveying roller pairs 40a-40d, thereby preventing skew.

[0055] FIG. 27(a) is a schematic diagram of the shift roller pair 13 of this embodiment when it is shifted to the front side, and FIG. 27(b) is a graph showing the pressure applied to the paper by each conveying roller pair at that time. As shown in FIG. 27(a), even when the shift roller pair 13 is shifted toward the front, the swinging of the connecting member 30 is restricted by the side of the groove portion, which serves as a restricting portion. Therefore, the postures of the first driven roller shaft 131b1 and the second driven roller shaft 131b2 hardly change, and they can maintain a state in which they follow the drive roller shaft 131a. Therefore, as shown in FIG. 27(b), the pressure applied to the paper by each of the conveying roller pairs 40a-40d can be maintained. This prevents slippage of the paper at each of the conveying roller pairs 40a-40d, and reduces skew.

[0056] [Variation 1] FIG. 28 is a schematic diagram showing a first modified example. As shown in Fig. 28, spherical portions 133a, 133b are provided at the rear end of the first driven roller shaft 131b1 and the front end of the second driven roller shaft 131b2, which are connected to the connecting member 30A of this first modified example. Holes 38a, 38b, each with a spherical inner circumferential surface, are provided at both axial ends of the connecting member 30A. The spherical portions 133a, 133b of the driven roller shafts 131b1, 131b2 engage with the holes 38a, 38b, thereby connecting the first driven roller shaft 131b1 and the second driven roller shaft 131b2 via the connecting member 30A. Each hole 38a, 38b of the connecting member 30A is provided with a notch 37.

[0057] FIG. 29 is a diagram illustrating the dimensional relationship of the first modified example. When the width of the notch 37 of the connecting member 30A is C, the diameter of the spherical portions 133a and 133b of the driven roller shaft is B, and the diameter of the hole portions 38a and 38b of the connecting member is A, the relationship A>B>C is satisfied. By satisfying A>B, a gap is formed between the hole portions 38a and 38b of the connecting member 30A and the spherical portions 133a and 133b. This allows the connecting member 30A to smoothly swing relative to each driven roller shaft 131b1 and 131b2 within a predetermined range. Furthermore, each driven roller 131b1 and 131b2 can rotate smoothly together with the driven conveying roller. Furthermore, the relationship B>C prevents the spherical portions 133a and 133b from easily slipping out of the notch 37.

[0058] In the first modified example, as in the embodiment, connecting member 30A is elastically deformable so as to expand the width of notch 37. When spherical portions 133a and 133b are fitted into holes 38a and 38b, spherical portions 133a and 133b are pushed through notch 37 of connecting member 30A. This causes connecting member 30A to elastically deform so as to expand the width of notch 37, and spherical portions 133a and 133b are pushed into holes 38a and 38b, and spherical portions 133a and 133b are fitted into holes 38a and 38b. By setting the difference (BC) between the diameter B of the spherical portions 133a, 133b and the width C of the cutout portion 37 to at least 0.3 to several mm (approximately 0.5 mm in this embodiment), it is possible to maintain ease of assembly while preventing the spherical portions 133a, 133b from easily coming out of the cutout portion 37. Furthermore, even with this configuration, the first driven roller shaft 131b1 and the second driven roller shaft 131b2 can be connected with a single connecting member, which prevents an increase in the number of parts and reduces the cost of the device.

[0059] In the first modification, the ends of the driven roller shafts 131b1 and 131b2 attached to the connecting member 30A are spherical, and the holes 38a and 38b of the connecting member 30A into which the ends of the driven roller shafts 131b1 and 131b2 are attached are spherical. This allows the driven roller shafts 131b1 and 131b2 to be smoothly tilted relative to the connecting member 30A. This allows the driven roller shafts 131b1 and 131b2 to effectively follow the deflected drive roller shaft 131a, effectively preventing a decrease in the pressure applied to the paper by the axially central conveying roller pairs 40b and 40c.

[0060] FIG. 30(a) is a diagram illustrating a case where the shift driven roller 13b is shifted toward the rear side in the first modified example, and FIG. 30(b) is a diagram illustrating a case where the shift driven roller 13b is shifted toward the front side in the first modified example. As shown in Figure 30(a), when the shift mechanism 60 moves the first driven roller shaft 131b1 to the rear, the spherical portion 133a of the first driven roller shaft 131b1 pushes the connecting member 30A diagonally downward to the left in the figure. This pushing causes the connecting member 30A to swing clockwise in the figure, and the front end of the connecting member 30A hits the bottom surface of the groove portion 132a of the first driven roller shaft 131b1 (see W5 in the figure). This hit pushes the bottom surface of the groove portion of the first driven roller shaft 131b1 toward the shift drive roller 13a. The shift driven roller 13b is supported by the shift drive roller 13a, which is supported on both side plates 34a, 34b so as not to be able to move in the vertical direction. Therefore, the rigidity of the shift drive roller 131a prevents the rear end of the first driven roller shaft 131b1 from moving toward the shift drive roller from a state in which the first driven roller shaft 131b1 follows the drive roller shaft 131a. Therefore, even if the front end of the connecting member 30A abuts against the bottom surface of the groove 132a of the first driven roller shaft 131b1 and the rear end of the first driven roller shaft is pushed toward the shift drive roller, the rear end of the first driven roller shaft does not move toward the shift drive roller. As a result, clockwise swing of the connecting member 30 in the figure is restricted. This allows the driven roller shafts 131b1 and 131b2 to move toward the rear while substantially maintaining the posture shown in FIG. 30(a). Therefore, during shifting toward the rear, the driven roller shafts 131b1 and 131b2 can be maintained in a state in which they follow the drive roller shaft 131a.

[0061] As shown in FIG. 30(b), when the shift mechanism 60 moves the first driven roller shaft 131b1 toward the front, the spherical portion 133a of the first driven roller shaft 131b1 pushes the connecting member 30 diagonally upward to the right in the figure. This push causes the connecting member 30A to rotate slightly counterclockwise in the figure, and the rear end of the connecting member 30 abuts against the bottom surface of the groove portion 132b of the second driven roller shaft 131b2 (see W6 in the figure). For the same reason as described with reference to FIG. 30(a), counterclockwise oscillation of the connecting member 30A in the figure is restricted. As a result, the driven roller shafts 131b1 and 131b2 move toward the front while substantially maintaining the posture shown in FIG. 30(b). Therefore, when shifting toward the front, the driven roller shafts 131b1 and 131b2 can be maintained in a state following the drive roller shaft 131a.

[0062] In this first modified example, the bottom surfaces of the grooves 132a and 32b function as restricting portions that restrict the swing of the connecting member 30A during a shift operation. Note that the width (axial length) of the grooves 132a and 32b may be narrowed so that the connecting member 30A abuts against the side surface of the groove when it swings, and the side surface of the groove restricts the swing of the connecting member during a shift operation.

[0063] [Variation 2] FIG. 31 is a schematic diagram showing a second modified example. The connecting member 30B in this second modified example has a cylindrical shape and is provided with through holes 39a, 39b on the rear and front sides, through which the engagement pin 41 passes. Engagement holes 134a, 134b, with which the engagement pin 41 engages, are provided on the rear end of the first driven roller shaft 131b1 and the front end of the second driven roller shaft 131b2, respectively.

[0064] The rear end of the first driven roller shaft 131b1 and the front end of the second driven roller shaft 131b2 are inserted into the insertion holes 42 of the connecting member 30B. Then, the engaging pin 41 is inserted through the through holes 39a and 39b, and the tip of the engaging pin 41 is inserted into the engaging holes 134a and 134b of the driven roller shafts 131b1 and 131b2, respectively, whereby the first driven roller shaft 131b1 and the second driven roller shaft 131b2 are connected by the connecting member 30B.

[0065] FIG. 32 is a diagram illustrating the dimensional relationship of the second modified example. When the diameter (inner diameter) of the insertion hole of the connecting member 30B is A and the diameter of each of the driven roller shafts 131b1 and 131b2 is B, the relationship A>B is satisfied. Furthermore, when the diameter (inner diameter) of the engagement holes 134a and 134b is C and the diameter of the engagement pin 41 is D, the relationship C>D is satisfied. As a result, gaps are formed between the driven roller shafts 131b1 and 131b2 and the insertion hole 42, and gaps are formed between the engagement pin 41 and the engagement holes 134a and 134b. As a result, the connecting member 30B can swing relative to each of the driven roller shafts 131b1 and 131b2 within a predetermined range.

[0066] The engagement holes 134a and 134b may be elongated in the axial direction, and the length of the engagement holes 134a and 134b in the paper transport direction (the direction perpendicular to the paper surface in the drawing) may be set to be approximately the same as the diameter of the engagement pin 41. With this configuration, it is possible to prevent the driven roller shafts 131b1 and 131b2 from tilting in the transport direction with respect to the connecting member 30B.

[0067] In this second modified example, the only processing required for the driven roller shafts 131b1 and 131b2 is hole processing for forming the engagement holes, and the processing range for the driven roller shafts can be reduced compared to the embodiment and the first modified example.

[0068] FIG. 33(a) is a diagram illustrating the case where the shift driven roller 13b is shifted toward the rear side in the second modified example, and FIG. 33(b) is a diagram illustrating the case where the shift driven roller 13b is shifted toward the front side in the second modified example. As shown in FIG. 33(a), when the shift mechanism 60 moves the first driven roller shaft 131b1 toward the rear, the front end of the engagement hole 134a of the first driven roller shaft 131b1 abuts against the engagement pin 41, and the tip of the engagement pin 41 is pushed diagonally downward to the left in the figure. This pushing causes the engagement pin 41 to fall toward the front, resulting in the coupling member 30B swinging clockwise in the figure. Then, the front end 42a of the insertion hole 42 of the coupling member 30B abuts against the outer peripheral surface of the first driven roller shaft 131b1 (see W7 in the figure), restricting the rotation of the coupling member 30B. Furthermore, as the coupling member 30B swings clockwise in the figure, the tip of the engagement pin 41 engaged with the engagement hole 134b of the second driven roller shaft 131b2 abuts against the inner peripheral surface of the engagement hole 134b (see W8 in the figure). This abutment can also restrict the swinging of the connecting member 30B to some extent.

[0069] As a result, the second driven roller shaft 131b2 can be moved to the rear side with almost no swinging of the connecting member 30, and the second driven roller shaft 131b2 moves to the rear side while substantially maintaining the posture shown in Fig. 33(a). Therefore, when shifting to the rear side, the driven roller shafts 131b1 and 131b2 can be maintained in a state of following the driving roller shaft 131a.

[0070] As shown in FIG. 33(b), when the shift mechanism 60 moves the first driven roller shaft 131b1 toward the front, the rear end of the engagement hole 134a of the first driven roller shaft 131b1 abuts against the engagement pin 41, and the engagement pin 41 is pushed diagonally upward to the right in the figure. This pushing causes the engagement pin 41 to tilt toward the rear, resulting in the coupling member 30B swinging counterclockwise in the figure. When the coupling member 30B swings slightly counterclockwise in the figure, the rear end 42b of the insertion hole 42 of the coupling member 30B abuts against the outer peripheral surface of the second driven roller shaft 131b2 (see W9 in the figure). This restricts the coupling member 30B from swinging counterclockwise in the figure. Furthermore, as the connecting member 30B swings counterclockwise in the figure, the tip of the engaging pin 41 engaged with the engaging hole 134b of the second driven roller shaft 131b2 hits the inner circumferential surface of the engaging hole 134b (see W10 in the figure). This hitting also serves to restrict the swinging of the connecting member 30B to some extent.

[0071] As a result, the connecting member 30 can be moved toward the front side with almost no swinging, and the first driven roller shaft 131b1 moves toward the front side while substantially maintaining the posture shown in Fig. 33(b). Therefore, when shifting toward the front side, the driven roller shafts 131b1 and 131b2 can be maintained in a state of following the driving roller shaft 131a.

[0072] In the above description, the first driven roller shaft 131b1 and the second driven roller shaft 131b2 are connected by a connecting member at the center in the axial direction, but as shown in Fig. 34(a), the first driven roller shaft 131b1 and the second driven roller shaft 131b2 may be connected by a connecting member between the rear transport roller pair 40a and the second transport roller pair 40b from the rear.Also, as shown in Fig. 35(a), the first driven roller shaft 131b1 and the second driven roller shaft 131b2 may be connected by a connecting member between the front transport roller pair 40d and the second transport roller pair 40c from the front.

[0073] 34(a) and 35(a), the first driven roller shaft 131b1 and the second driven roller shaft 131b2 can be tilted with respect to the connecting member and can follow the deflected drive roller shaft. This makes it possible to suppress a decrease in the pressure applied to the paper by the axially inner conveying roller pair 40b, 40c, as shown in FIG. 34(b) and FIG. 35(b).

[0074] 36(a), the shift driven roller 13b may include a first driven roller shaft 131b1, a second driven roller shaft 131b2, and a third driven roller shaft 131b3. The first driven roller shaft 131b1 and the second driven roller shaft 131b2 are connected by a first connecting member 30-1, and the second driven roller shaft 131b2 and the third driven roller shaft 131b3 are connected by a second connecting member 30-2. The first driven roller shaft 131b1 and the second driven roller shaft 131b2 are tilted relative to the first connecting member 30-1, and the second driven roller shaft 131b2 and the third driven roller shaft 131b3 are tilted relative to the second connecting member 30-2, so that the shift driven roller 13b can follow the deflected drive roller shaft 131a. Therefore, as shown in FIG. 36(b), a decrease in the pressure applied to the paper by the axially inner conveying roller pair 40b, 40c can be suppressed.

[0075] While the preferred embodiment of the present invention has been described above, the present invention is not limited to such a specific embodiment. Unless otherwise specifically limited in the above description, various modifications and variations are possible within the spirit and scope of the present invention as defined in the claims. For example, while the shift driven roller 13b is disposed above the shift drive roller 13a in the above description, the shift driven roller 13b may be disposed below the shift drive roller 13a. Even with this configuration, the pressure of the pressure members 32a and 32b that press the shift driven roller 13b against the shift drive roller 13a causes the driven roller shafts 131b1 and 131b2 to tilt relative to the connecting member 30, allowing them to follow the bending of the drive roller shaft, thereby preventing a decrease in the pressure applied by each conveying roller pair to the paper.

[0076] The above description is merely an example, and each of the following aspects provides unique effects. (Aspect 1) In a sheet conveying device having a pair of conveying rollers for conveying a sheet such as paper P, The conveying roller pair is a shift roller pair 13 that can move in the width direction, which is a direction perpendicular to the sheet conveying direction, and is provided with a shift mechanism 60 that performs a shift operation to move the shift roller pair 13 in the width direction to shift the sheet in the width direction when the sheet is conveyed by the shift roller pair 13, and one of the pair of shift rollers, such as the shift driven roller 13b, has multiple roller shafts (131b1, 131b2) and a connecting member 30 that connects the roller shafts together and is capable of swinging relative to the roller shafts. When the roller shaft of the other of a pair of shift rollers is bent, the roller shaft of one shift roller does not follow the roller shaft of the other shift roller, and the contact pressure of the conveying rollers on the axial center of one of the multiple conveying rollers of one shift roller against the sheet becomes lower than the contact pressure of the conveying rollers on the axial end sides. As a result, the conveying rollers on the axial center side slip with respect to the sheet, which could cause the sheet to skew. In contrast, in aspect 1, one of the pair of shift rollers is configured with multiple roller shafts and a connecting member that connects the roller shafts and allows them to swing, so that when the roller shaft of the other shift roller is bent, each roller shaft of one shift roller can tilt with respect to the connecting member to follow the bending of the roller shaft of the other shift roller. This makes it possible to equalize the contact pressure of the multiple conveying rollers in contact with the sheet, thereby suppressing skew of the sheet.

[0077] (Aspect 2) In the first aspect, the roller shaft (131b1, 131b2) of one of the shift rollers has a restricting portion (in this embodiment, the side surface of the groove portions 132a, 132b) that abuts against the connecting member 30 and restricts the swinging of the connecting member 30 during a shift operation. As shown in FIG. 22(a), in a configuration in which the coupling member swings around coupling pins 231a and 231b as a fulcrum, or in which the swinging of the coupling member is not restricted, the following problem may occur during a shift operation. That is, during a shift operation, a shift device provided at one axial end of the roller shafts of the shift roller pair moves the roller shafts of the shift roller pair toward the other axial end, thereby shifting the pair of shift rollers. For one of the pair of shift rollers, whose roller shafts are connected by a coupling member, the roller shaft located at one axial end of the multiple roller shafts (hereinafter referred to as the roller shaft at one end) is moved toward the other axial end by the shift device. As this roller shaft at one end moves toward the other axial end by the shift device, the coupling member is pushed toward the other end by the roller shaft at one end. At this time, if the coupling member is tilted with respect to the roller shaft at one end, the pushing of the roller shaft at one end will cause the coupling member to swing (see FIG. 22(b)). When the connecting member swings during the shift operation in this way, one of the roller shafts on one end and the roller shaft on the other end connected to the roller shaft on the one end by the connecting member moves in a direction away from the sheet, which may cause the conveying rollers supported by the roller shaft to move away from the sheet or reduce the contact pressure with the sheet, resulting in problems such as poor conveyance, such as skewed sheets, during the shift operation. In contrast, in the second aspect, the connecting member abuts against the restricting portion during the shift operation, restricting the swinging. Therefore, the conveying roller of one of the shift rollers can be prevented from separating from the sheet during the shift operation. This can prevent conveyance problems such as skewed sheets during the shift operation.

[0078] (Aspect 3) In aspect 1 or 2, the ends of the two roller shafts (131b1, 131b2) connected to the connecting member 30 have a gap with respect to the connecting member 30 at least in the perpendicular direction that is perpendicular to both the conveying direction of the sheet such as paper P and the axial direction of the roller shaft, and are assembled within the connecting member 30 so as to be movable in the axial direction relative to the connecting member 30 within a predetermined range. According to this, as described in the embodiment, the connecting member 30 can be swung around the conveyance direction within a predetermined range. As a result, the roller shafts (131b1, 131b2) connected to the connecting member 30 can be tilted in a direction perpendicular to the connecting member 30, and the roller shafts (131b1, 131b2) can follow the bending of the roller shaft of the other shift roller, such as the shift drive roller 13a. This makes it possible to suppress a decrease in the pressure applied to sheets, such as paper, by the conveying roller pair 40b, 40c, which is provided near the center in the axial direction among the multiple conveying roller pairs 40a to 40d of the shift roller pair, thereby suppressing slippage of the sheet and reducing skew.

[0079] (Aspect 4) In any of aspects 1 to 3, the connecting member 30 is cylindrical and has holes 38 into which the ends of the two roller shafts connected to the connecting member 30 are assembled, and the roller shafts (131b1, 131b2) of the connecting member 30 have engaging protrusions 36a, 36b at both axial ends thereof that engage with grooves 132a, 132b provided on the end sides of each roller shaft connected to the connecting member 30. As described in the embodiment, this allows the engaging protrusions 36a, 36b to engage with the grooves 132a, 132b, thereby preventing the roller shafts (131b1, 131b2) from slipping out of the connecting member 30 in the axial direction. Furthermore, during a shift operation, the engaging protrusions 36a, 36b abut against the side surfaces of the grooves 132a, 132b, thereby restricting the swinging of the connecting member. In this way, the side surfaces of the grooves 132a, 132b can function as restricting portions.

[0080] (Aspect 5) In any of aspects 1 to 4, the ends of the two roller shafts (131b1, 131b2) connected to the connecting member 30 are spherical, and the connecting member 30 has spherical hole portions 38a, 38b at both axial ends of the roller shafts, into which the spherical ends of the roller shafts are assembled. As described in the first modified example, this allows each roller shaft (131b1, 131b2) to be smoothly tilted with respect to the connecting member, thereby allowing each roller shaft to be properly aligned with the bent roller shaft (131a) of the other shift roller, and effectively suppressing a decrease in the pressure applied to the paper by the conveying roller pair 40b, 40c at the axial center.

[0081] (Aspect 6) In the fourth or fifth embodiment, the hole of the connecting member has a partially cut-out shape. According to this, as described in the embodiment and the first modified example, by pushing the end of the roller shaft through the cutout portion 37 of the connecting member 30, the connecting member is elastically deformed so that the width of the cutout portion increases, and the end of the roller shaft can be assembled into the hole portion 38 of the connecting member 30. In this way, simply by pushing the end of the roller shaft through the cutout portion 37 of the connecting member 30, the end of the roller shaft can be assembled into the hole portion, making it easy to assemble each roller shaft into the connecting member.

[0082] (Aspect 7) In any of aspects 1 to 3, both axial ends of the roller shaft of the connecting member 30 are provided with insertion portions such as insertion holes 42 into which the ends of the roller shaft are inserted, and through holes 39a, 39b through which engaging members such as engaging pins pass, and the ends of the two roller shafts (131b1, 131b2) connected to the connecting member 30 are provided with engaging holes 134a, 134b into which the engaging members engage. As a result, as explained in the second modified example, the processing performed on the end side of each roller shaft for assembly to the connecting member 30 can be limited to hole processing, and the processing range for the roller shaft can be reduced compared to the embodiment and the first modified example.

[0083] (Aspect 8) In any of aspects 1 to 7, a plurality of pressure members 32a, 32b that pressurize one shift roller such as the shift driven roller 13b against the other shift roller such as the shift drive roller 13a are provided at predetermined intervals in the axial direction of the roller shaft, and the connecting member 30 is provided between the pressure members. This allows multiple roller shafts to be pressed against other shift rollers by at least one pressure member, which allows the pressure applied to sheets such as paper by the conveying rollers supported by each roller shaft to be set to a predetermined pressure, preventing slippage of the conveying rollers against the paper and effectively preventing skew of the sheet.

[0084] (Aspect 9) In a sheet processing apparatus provided with a sheet conveying means and a sheet processing means for performing a predetermined process on the sheet conveyed by the sheet conveying means, the sheet conveying device of any one of aspects 1 to 8 was used as the sheet conveying means. This can prevent the sheet from being skewed when the pair of shift rollers shifts the sheet in the width direction.

[0085] (Aspect 10) In an image forming apparatus that uses a sheet conveying means and performs an image forming process for forming an image on a sheet conveyed by the sheet conveying means, the sheet conveying means is a sheet conveying device according to any one of aspects 1 to 8. This can prevent the sheet from being skewed when the pair of shift rollers shifts the sheet in the width direction. [Explanation of symbols]

[0086] 1: Image forming system 13: Shift roller pair 13a: Shift drive roller 13b: Shift driven roller 17: Staple tray 19: Stapler 25: Shift motor 26: Timing belt 27: Movable parts 27a: First through hole 27b: Second through hole 28: Regulating member 29: Output gear 30: Connecting member 31a: pressure-receiving member 32a: Pressure member on the rear side 32b: Front pressure member 33a: Pressure fixing member 34a: Back board 34b: Front plate 35: Bearing 36a: Engagement protrusion 36b: Engagement protrusion 37: Notch 38: Hole 39a: Through hole 40a: Transport roller pair 40b: Transport roller pair 40c: Conveyor roller pair 40d: Transport roller pair 41: Engagement pin 42: Insertion hole 42a: Front end 42b: Back end 60: Shift mechanism 61: Wide gear 131a: Drive roller shaft 131b1: First driven roller shaft 131b2: Second driven roller shaft 131b3: Third driven roller shaft 132a:Groove 132b:Groove 133a: Spherical part 134a: Engagement hole 134b: Engagement hole 140a: Drive conveyor roller 140b: Follower conveying roller [Prior art documents] [Patent documents]

[0087] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-091731

Claims

1. In a sheet conveying device having a pair of conveying rollers for conveying a sheet, The conveying roller pair is a shift roller pair that is movable in the width direction, which is a direction perpendicular to the sheet conveying direction, a shift means for performing a shift operation of moving the pair of shift rollers in the width direction to shift the sheet in the width direction when the sheet is conveyed by the pair of shift rollers; 1. A sheet conveying device, wherein one of a pair of shift rollers has a plurality of roller shafts and a connecting member that connects the roller shafts together and is swingable relative to the roller shafts.

2. 2. The sheet conveying device according to claim 1, The sheet conveying device according to claim 1, wherein the roller shaft of one of the shift rollers includes a restricting portion that abuts against the connecting member during the shift operation to restrict the swinging of the connecting member.

3. 2. The sheet conveying device according to claim 1, A sheet conveying device characterized in that the ends of the two roller shafts connected to the connecting member have a gap with respect to the connecting member at least in a direction perpendicular to both the sheet conveying direction and the axial direction of the roller shaft, and are assembled within the connecting member so as to be movable relative to the connecting member in the axial direction within a predetermined range.

4. 2. The sheet conveying device according to claim 1, the connecting member has a cylindrical shape and includes holes into which ends of two roller shafts connected to the connecting member are assembled, A sheet conveying device characterized in that the connecting member has engaging protrusions at both ends in the axial direction of the roller shafts, which engage with grooves provided on the end sides of each roller shaft connected to the connecting member.

5. 2. The sheet conveying device according to claim 1, The ends of the two roller shafts connected to the connecting member are spherical, a connecting member provided at each end in the axial direction of the roller shaft with a hole having a spherical inner circumferential surface, into which the spherical end of the roller shaft is fitted;

6. 6. The sheet conveying device according to claim 4, The sheet conveying device according to claim 1, wherein the hole of the connecting member has a shape in which a part of the hole is cut out.

7. 2. The sheet conveying device according to claim 1, The connecting member is provided at both ends in the axial direction of the roller shaft with an insertion portion into which an end of the roller shaft is inserted and a through hole through which an engaging member passes, The sheet conveying device is characterized in that the ends of the two roller shafts connected to the connecting member are provided with engagement holes with which the engagement members engage.

8. 2. The sheet conveying device according to claim 1, a plurality of pressure members for pressing one of the shift rollers against the other shift roller are provided at predetermined intervals in the axial direction of the roller shaft; The sheet conveying device according to claim 1, wherein the connecting member is provided between the pressure members.

9. A sheet conveying means; a sheet processing means for performing a predetermined process on the sheet conveyed by the sheet conveying means, 2. A sheet processing apparatus comprising the sheet conveying device according to claim 1 as said sheet conveying means.

10. A sheet conveying means; In an image forming apparatus that performs an image forming process to form an image on a sheet conveyed by the sheet conveying means, 10. An image forming apparatus comprising the sheet conveying device according to claim 1 as said sheet conveying means.

Images