Sheet conveying device and image forming apparatus

Abstract

To provide a sheet conveying device and an image forming device capable of stabilizing sheet transport by reducing or eliminating the portion where the guides of the guide members at the confluence part are interrupted when a sheet transported in the transport path passes through the confluence part, thereby making it difficult to give resistance to the sheet.SOLUTION: A sheet conveying device 10 according to the present invention has a plurality of conveying paths for conveying sheets, wherein at least two conveying paths among the plurality of conveying paths are joined at a confluence part G. The sheet conveying device includes: a movable guide 81 that operates toward a portion (SP) where the guide of a guide member 10A constituting one of the at least two transport paths (L2) at the confluence part G is interrupted; and a movable guide operating unit that operates the movable guide 81 in accordance with the operation of a transport roller 11 that transports the sheet from the one transport path (L2) to the confluence part G so as to reduce or eliminate the portion (SP) where the guides of the guide members 10A are interrupted when the sheet enters the junction G from the one transport path (L2).SELECTED DRAWING: Figure 6A

Description

[Technical field]

[0001] The present disclosure relates to a sheet transport device that transports a sheet, and an image forming apparatus such as a copying machine, a multifunction machine, a printer, or a facsimile machine. [Background technology]

[0002] Typically, a sheet conveying device that supplies or discharges a sheet (paper) that is a recording medium has multiple conveying paths, and at a junction where at least two of the multiple conveying paths join, there is a portion where the guide of the guide member is interrupted. For this reason, the sheet is likely to vibrate when passing through the junction. In particular, when a sheet is conveyed to a conveying path that joins while curving, the leading edge of the sheet comes into contact with the connecting guide member when passing through the junction, and then the traveling direction is changed, which increases the sheet conveying load, and further, the trailing edge of the sheet bounces off the connecting guide member, which may cause impact noise and deterioration of image quality due to vibration.

[0003] In response to this, for example, Patent Document 1 discloses a structure in which a support film is installed as a support means at the junction of a curved reversing discharge path leading to a sheet discharge roll and a straight discharge path, so that the sheet from the curved reversing discharge path is supported by the support film when it moves to the straight discharge path, allowing the sheet to move to the discharge path without its rear end colliding with a guide member.

[0004] Patent Document 2 also discloses a structure in which, at the junction where the conveying path toward the pre-registration guide and the curved reversing conveying path join, a movable guide is provided having a support shaft installed along the width direction of the conveyed sheet and a film member arranged to separate the conveying paths at the junction, so that the leading edge of the sheet conveyed to the junction pushes the film member to rotate the movable guide, and the rear end is guided to the vicinity of the pre-registration guide without colliding with the guide member. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-147175 [Patent Document 2] JP 2017-30937 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the structure disclosed in Patent Document 1, the support film is made of a flexible film-like member, is arranged so as to protrude into the discharge path toward the sheet discharge roll, and is fixed to the guide member on the reverse discharge path side by adhering or bonding with double-sided tape, etc. Therefore, there are problems in that if the film is thin, the guide performance and durability are insufficient, if the film is thick, the resistance applied to the sheet is large, and if the size of the film protruding into the discharge path side is small, the guide is insufficient, and if the size of the film protruding into the discharge path side is large, the passage of the sheet from the discharge path side is hindered.

[0007] Furthermore, in the structure disclosed in Patent Document 2, the leading edge of the transported sheet pushes against the film member, causing the movable guide to rotate in a direction to widen the path through which the sheet passes. This creates problems in that resistance is applied to the sheet, and if the sheet is hard, the leading edge will collide strongly with the film member, and if the sheet is soft, the movable guide cannot be rotated sufficiently.

[0008] The present disclosure has been made to solve the problems described above, and aims to provide a sheet conveying device and an image forming apparatus that can reduce resistance to a sheet being conveyed along a conveying path when the sheet passes through a junction, and can stabilize sheet conveyance by reducing or eliminating the portions at the junction where the guide member's guide is interrupted. [Means for solving the problem]

[0009] In order to solve the above problem, the sheet transporting device according to the present disclosure is a sheet transporting device having a plurality of transport paths for transporting a sheet, at least two of the plurality of transport paths joining at a junction, and is characterized in that it is equipped with a movable guide that operates toward a portion where a guide of a guide member constituting one of the at least two transport paths at the junction is interrupted, and a movable guide operating portion that operates the movable guide in accordance with the operation of a transport roller that transports the sheet from the one transport path to the junction, so as to reduce or eliminate the portion where the guide is interrupted when the sheet enters the junction from the one transport path.

[0010] In another aspect of the present disclosure, an image forming apparatus includes the above-described sheet conveying device. Effect of the Invention

[0011] According to the present disclosure, it is possible to reduce resistance to a sheet being transported along a transport path when the sheet passes through a junction, and it is possible to reduce or eliminate portions where the guide of the guide member at the junction is interrupted, thereby achieving stabilization of sheet transport at the junction.

[0012] The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description of the embodiments, which proceeds with reference to the drawings. [Brief description of the drawings]

[0013] [Figure 1] 1 is a schematic cross-sectional view illustrating a basic configuration of an image forming apparatus to which a sheet conveying device according to each embodiment of the present disclosure is applied. [Diagram 2] 1 is a schematic diagram illustrating a general structure of a junction portion where a sheet supply path and a reverse conveying path join together in a basic configuration of a sheet conveying device according to each embodiment of the present disclosure; [Figure 3A] 1 is a schematic diagram showing a state when a sheet passes through a junction in a conventional sheet conveying device. [Figure 3B]1 is a schematic diagram showing a state when a sheet passes through a junction in a conventional sheet conveying device. [Figure 3C] 1 is a schematic diagram showing a state when a sheet passes through a junction in a conventional sheet conveying device. [Figure 4] 3 is a perspective view showing a part of a roller support body on which a movable guide is provided in the first embodiment. FIG. [Figure 5A] 4 is a cross-sectional view illustrating a schematic configuration of a junction portion and the surrounding area of ​​the example of the sheet conveying device according to the first embodiment. FIG. [Figure 5B] 3 is a cross-sectional view illustrating a schematic configuration of a junction portion and the surrounding area of ​​an example of a sheet conveying device according to the first embodiment. FIG. [Figure 6A] 11 is a cross-sectional view illustrating a schematic configuration of a junction portion and its surroundings in another example of a sheet conveying device according to the second embodiment. FIG. [Figure 6B] 11 is a cross-sectional view illustrating a schematic configuration of a junction portion and its surroundings in another example of a sheet conveying device according to the second embodiment. FIG. [Figure 7A] 13 is a cross-sectional view illustrating a schematic configuration of a junction portion and its surroundings in still another example of a sheet conveying device according to the third embodiment. FIG. [Figure 7B] 13 is a cross-sectional view illustrating a schematic configuration of a junction portion and its surroundings in still another example of a sheet conveying device according to the third embodiment. FIG. [Figure 8] FIG. 11 is a block diagram showing an example of a system configuration of a movable guide operation unit in the third embodiment. [Figure 9] 11 is a flowchart showing an example of a process performed by a control unit of a movable guide operation unit in the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, an embodiment of a sheet conveying device and an image forming apparatus according to the present disclosure will be described with reference to the drawings. In the following description, the same components are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

[0015] <Embodiment 1> Fig. 1 is a schematic cross-sectional view showing a basic configuration of an image forming apparatus 1 including a sheet conveying device 10 according to the first embodiment of the present disclosure. In Fig. 1, a surface on which an operation unit (not shown) is provided is defined as a front surface (front), and this defines a front-rear direction X (depth direction), a left-right direction Y, and a height direction Z of the image forming apparatus 1 and its components.

[0016] In this embodiment, the image forming apparatus 1 is a multifunction peripheral (MFP) having a copy function, a printer function, a scanner function, a facsimile function, etc. First, the basic configuration of the image forming apparatus 1 will be roughly described with reference to FIG.

[0017] The image forming device 1 comprises an apparatus main body 1a and an image reading device 20 arranged on top of it, and forms a multi-color or monochrome image on a specified sheet P (recording medium, hereinafter referred to as the sheet) based on image data read by the image reading device 20 or image data transmitted from an external information terminal.

[0018] The image reading device 20 includes a document placement table made of a transparent material and a document pressing cover that is attached so as to be freely opened and closed. Although not shown, an operation unit such as a touch panel and operation buttons that accept input operations by a user is provided on the front side (near side) of the document placement table.

[0019] In addition, the image reading device 20 is equipped with a light source, multiple mirrors, an imaging lens, a line sensor, etc., and is configured to expose the surface of the document to the light source, guide the reflected light from the document surface to the imaging lens via multiple mirrors, image the reflected light on a light-receiving element of the line sensor via the imaging lens, detect the luminance or chromaticity of the reflected light imaged on the light-receiving element by the line sensor, and generate image data based on the image of the document surface.

[0020] The apparatus main body 1a includes a main control unit (not shown) that controls the entire image forming apparatus 1, an image forming unit 30, a sheet conveying device 10, and the like.

[0021] The main control unit has a built-in CPU, RAM, etc., and is configured to send control signals to each component of the image forming apparatus 1 to perform various operations in response to input operations by a user on the operation unit, etc.

[0022] The image forming section 30 includes an exposure unit 31, a developing unit 32, a photosensitive drum 33, a cleaner unit 34, a charger 35, an intermediate transfer belt unit 36, a secondary transfer roller 38, and a fixing unit 39, and is configured to form an image on a sheet P fed from a paper feed cassette 41 or a manual feed tray 42, etc., and to discharge the sheet P with the image formed thereon to a paper output tray 60.

[0023] The image data for forming an image on the sheet P includes image data read by the image reading device 20, as well as image data transmitted from an external information terminal.

[0024] The image data handled by the image forming apparatus 1 corresponds to a color image of, for example, four colors, black (K), cyan (C), magenta (M) and yellow (Y). For this reason, four of each of the developing device 32, the photoconductor drum 33, the cleaner unit 34 and the charger 35 are provided so as to form four types of latent images corresponding to each color, and these constitute four image stations.

[0025] The photoconductor drum 33 is an electrostatic latent image carrier in which a photosensitive layer is formed on the surface of a cylindrical base body having electrical conductivity. The charger 35 charges the surface of the photoconductor drum 33 to a predetermined potential. The exposure unit 31 is configured as a laser scanning unit (LSU) equipped with a laser emission section and a reflecting mirror, and exposes the charged surface of the photoconductor drum 33 to light, thereby forming an electrostatic latent image on the surface of the photoconductor drum 33 according to image data. The developer 32 visualizes the electrostatic latent image formed on the surface of the photoconductor drum 33 with four-color (YMCK) toners. The cleaner unit 34 removes and collects toner remaining on the surface of the photoconductor drum 33 after development and image transfer.

[0026] The intermediate transfer belt unit 36 ​​includes an intermediate transfer belt 361, a transfer driving roller 362, a transfer driven roller 363, and four intermediate transfer rollers 364, and constitutes an image carrier. The intermediate transfer belt 361 is provided so as to contact each photosensitive drum 33. The intermediate transfer rollers 364 are used to transfer the toner images of each color formed on each photosensitive drum 33 to the intermediate transfer belt 361 in a sequentially overlapping manner, thereby forming a multi-color toner image on the intermediate transfer belt 361. A secondary transfer roller 38 of the transfer section 37 is disposed near the transfer driving roller 362. The toner image formed on the intermediate transfer belt 361 is transferred to the surface of the sheet P by the sheet P passing through a transfer nip portion between the intermediate transfer belt 361 and the secondary transfer roller 38.

[0027] The fixing unit 39 includes a fixing roller 391, a heating roller 392, and a pressure roller 393. The fixing roller 391 is pressed against the pressure roller 393 via a belt suspended between the fixing roller 391 and the heating roller 392. The toner image on the sheet P is heated and fixed by the sheet P being conveyed while being sandwiched in the fixing nip portion between the fixing roller 391 and the pressure roller 393 via the belt.

[0028] The sheet conveying device 10 includes a sheet supply path L1 (an example of another conveying path) and a sheet conveying path L3 (an example of a conveying path after merging), a paper feed roller 49 and a conveying roller 51 for conveying a sheet P placed in a paper feed cassette 41, a pre-registration roller 52, a registration roller 53, a manual paper feed roller 55, and a driven roller 56.

[0029] The manual feed roller 55 conveys the sheet P placed on the manual feed tray 42 toward the pre-registration roller 52. The driven roller 56 rotates in opposition to the manual feed roller 55. The manual feed roller 55 and the driven roller 56 are disposed upstream of the conveying roller 11 described later.

[0030] The sheet transport path L3 is provided with pre-registration rollers 52, registration rollers 53, secondary transfer rollers 38, fixing rollers 391, pressure rollers 393, post-fixing rollers 54 and discharge rollers 57, and is composed of multiple guide members that guide the sheet P passing through.

[0031] The sheet supply path L1 is provided with a paper feed roller 49, a transport roller 51, and the like, and is made up of a plurality of guide members that guide the sheet P passing therethrough.

[0032] The sheet supply path L1 transports the sheet P sent from the paper feed cassette 41. The sheet transport path L3 transports the sheet P sent from a later-described reverse transport path L2 (an example of one transport path), the manual feed tray 42, and the sheet supply path L1. The sheet supply path L1 and the reverse transport path L2 join at a joining point G upstream of the pre-registration rollers 52 disposed upstream of the registration rollers 53 in the sheet transport direction H, and communicate with the sheet transport path L3.

[0033] In detail, rollers on the sheet transport path L3, such as the pre-registration rollers 52, the registration rollers 53, the post-fixing rollers 54, and the paper discharge rollers 57, are provided with respective pairs of driven rollers facing each other and function to sandwich and transport the sheet P. The sheet transport path L3 guides the sheet P transported to the pre-registration rollers 52 to the paper discharge tray 60 via the registration rollers 53, the transfer section 37, the fixing unit 39, the post-fixing rollers 54, and the paper discharge rollers 57.

[0034] A pair of driven rollers such as the conveying roller 51 on the sheet supply path L1 is provided opposite to each other and acts to sandwich and convey the sheet P. The sheet supply path L1 guides the sheet P supplied to the conveying roller 51 by the paper feed roller 49 to the sheet conveying path L3.

[0035] The sheet conveying device 10 further includes a reversing conveying path L2. The reversing conveying path L2 returns the sheet P, which has passed through the fixing unit 39 after the front side printing is completed when performing double-sided printing on the sheet P, to the sheet conveying path L3 upstream of the transfer unit 37 in the sheet conveying direction H.

[0036] The reverse conveying path L2 is provided with a conveying roller 11 that conveys the sheet P toward the sheet conveying path L3, a driven roller 12 that rotates driven by the conveying roller 11, and a plurality of guide members that guide the sheet P. The reverse conveying path L2 conveys the inverted sheet P toward the pre-registration roller 52 while sandwiching it between the conveying roller 11 and the driven roller 12. The reverse conveying path L2 is provided so as to communicate with the sheet conveying path L3 at the junction G. The reverse conveying path L2 guides the sheet P, which has passed through the image forming unit 30 and has been drawn back into the sheet conveying path L3 by the discharge roller 57, to the image forming unit 30 in a reversed state so that the side on which the toner image is not transferred is the side that contacts the intermediate transfer belt 361.

[0037] The sheet conveying path L3 is provided so as to communicate with the sheet supply path L1 and the reversing conveying path L2 at a junction G.

[0038] FIG. 2 is a schematic diagram showing a structure around a junction G where a sheet supply path L1 and a reverse conveying path L2 join together in a basic configuration of the sheet conveying device 10 according to this embodiment.

[0039] 2, a roller support 70 is disposed between the sheet supply path L1 and the reverse transport path L2 and is disposed in the sheet transport device main body 10a and extends toward the sheet transport path L3. The transport roller 11, the transport roller 51, the driven roller 56, and the like are attached to the roller support 70. The roller support 70 is fixed to the sheet transport device main body 10a (device main body 1a) and supports the rollers (11, 51, 56), with its lower surface forming a component of the sheet supply path L1 and its upper surface forming a component of the reverse transport path L2.

[0040] On the upper surface of roller support 70, manual feed roller 55 and driven roller 56 transport sheet P placed on manual tray 42 upstream of transport roller 11 toward transport roller 11 and driven roller 12, and transport roller 11 and driven roller 12 transport sheet P transported to reversal transport path L2 and sheet P transported from manual tray 42 toward sheet transport path L3. On the lower surface of roller support 70, transport roller 51 and driven roller 50 transport sheet P sent from paper feed cassette 41 along sheet supply path L1 toward sheet transport path L3.

[0041] At the tip of the roller support 70 (the portion located downstream of the conveying roller 11), a tongue-shaped member (with an acute triangular cross section) that thins while extending toward the pre-registration roller 52 is provided as a junction guide member 10A. This junction guide member 10A is a guide member that constitutes the reverse conveying path L2 (one example of one conveying path) at the junction G. The sheet supply path L1 and the reverse conveying path L2 merge with the sheet conveying path L3 via the junction guide member 10A at the junction G upstream of the pre-registration roller 52. In other words, the junction guide member 10A is located upstream of the junction G of the sheet supply path L1 and the reverse conveying path L2, and guides the sheet P conveyed to the sheet supply path L1 and the sheet P conveyed to the reverse conveying path L2 to the junction G.

[0042] A plurality of frame bodies are provided in each of the sheet supply path L1, the reverse conveying path L2, and the sheet conveying path L3. At the junction G, an upper guide member 10B extending from the reverse conveying path L2 side toward the pre-registration roller 52, and a transition guide member 10C (lower guide member) extending from a lower portion of the junction guide member 10A toward the pre-registration roller 52 are provided on the sheet conveying path L3 side.

[0043] As shown in FIG. 2, the reversing conveying path L2 and the sheet conveying path L3 form a curved conveying path in which the traveling direction is changed by a predetermined angle (for example, the maximum angle of the sheet conveying path L3 relative to the reversing conveying path L2 is 15 degrees) or more (for example, turning back at an angle of 180 degrees or more and 220 degrees or less).

[0044] 3A to 3C are schematic diagrams showing a state when a sheet P passes through a junction G in a conventional sheet conveying device.

[0045] In the conventional structure, as shown in Fig. 3A, when the sheet P being conveyed to the reverse conveying path L2 enters the junction G along the upper surface of the junction guide member 10A, the leading edge of the sheet P contacts the transfer guide member 10C where the sheet P transfers, and then, as shown in Fig. 3B, the sheet P changes direction and transfers to the sheet conveying path L3, which increases the conveying load. Furthermore, when the trailing edge of the sheet P leaves the junction guide member 10A as shown in Fig. 3C, it collides with the transfer guide member 10C as if being bounced, which may cause an impact sound or deterioration of image quality due to vibration.

[0046] In other words, when viewed from the reverse conveying path L2 side, there is a portion where the guide of the junction guide member 10A is interrupted (hereinafter, simply referred to as the "interrupted portion of the junction guide member 10A") at the junction G, so a space (the interrupted portion SP of the junction guide member 10A) is formed between the tip of the junction guide member 10A and the transfer guide member 10C. Therefore, the above problem is caused.

[0047] In contrast, the sheet transport device 10 according to the present embodiment is configured such that the junction guide member 10A acts as a movable guide 71 (see FIGS. 4, 5A, and 5B described later) in the basic configuration of the sheet transport device 10 shown in Fig. 2. This makes it possible to reduce or eliminate the interrupted portion SP of the junction guide member 10A when the sheet P transported to the reverse transport path L2 passes through the junction G.

[0048] FIG. 4 is a perspective view showing a part of the roller support 70 provided with the movable guide 71 in this embodiment, as viewed from above the sheet P being conveyed.

[0049] As shown in Fig. 4, the conveying roller 11 is supported by a rotating shaft 13 arranged on a roller support 70 along the surface of the sheet P perpendicular to the sheet conveying direction H, and is provided to rotate in a predetermined rotation direction F1. The conveying roller 11 has four roller portions 111 arranged on the rotating shaft 13 at intervals. The rotating shaft 13 is attached to a roller support 70 fixed to the sheet conveying device main body 10a, and is connected to a driving means (not shown) so as to be driven to rotate. When each roller portion 111 rotates in the rotation direction F1 with the rotation of the rotating shaft 13, the sheet conveying device 10 conveys the sheet P in contact with each roller portion 111 from the reverse conveying path L2 toward the junction G.

[0050] In this embodiment, the junction guide member 10A in the basic configuration of the sheet conveying device 10 shown in Fig. 2 is configured to act as a movable guide 71 shown in Fig. 4. The movable guide 71 is configured to be able to swing about the swing axis of a swing shaft 73 that is disposed perpendicular to the sheet conveying direction H and along the sheet P surface relative to the roller support 70. Specifically, the movable guide 71 is freely swingable about the swing axis of the swing shaft 73 with the swing shaft 73 (support shaft) as a fulcrum upstream of the rotation shaft 13. The base end of the movable guide 71 is attached to the roller support 70, and the tip end extends toward the junction G.

[0051] The movable guide 71 includes a main body 711 and an end plate 713. The main body 711 is provided with a plurality of guide ribs 712 spaced apart from one another, the guide ribs 712 tapering as they extend toward the junction G along the sheet conveying direction H, and extends in the direction of the oscillation axis K of the oscillation shaft 73 perpendicular to the sheet conveying direction H. The end plate 713 supports the main body 711 from both ends. The movable guide 71 guides the sheet P conveyed by the conveying roller 11 and the driven roller 12 along the upper surface of the main body 711 to the junction G.

[0052] 5A and 5B are cross-sectional views that show a schematic structure of the junction G and the surrounding area of ​​the sheet conveying device 10 according to the present embodiment, and show the movable guide 71 as viewed from the right side of Fig. 4. Fig. 5A shows a state in which the rotating shaft 13 is not rotating and the movable guide 71 is not operating, and Fig. 5B shows a state in which the rotating shaft 13 is rotating and the movable guide 71 is operating.

[0053] 5A and 5B, the sheet conveying device 10 further includes a movable guide operation unit 700. The movable guide operation unit 700 operates the movable guide 71 in response to the operation of the conveying roller 11 that conveys the sheet P from one conveying path (the reverse conveying path L2 in this example) of at least two conveying paths (the sheet supply path L1 and the reverse conveying path L2) to the junction G, so as to reduce or eliminate the interrupted portion SP when the sheet P enters the junction G from the reverse conveying path L2.

[0054] According to the above configuration, when the sheet P heading toward the junction G from one conveying path (L2) passes through the conveying roller 11, the movable guide 71 is operated toward the interrupted portion SP of the junction guide member 10A at the junction G, so that it is possible to make it difficult for the sheet P to resist, and to reduce or eliminate the interrupted portion SP of the junction guide member 10A. In other words, regardless of the hardness (rigidity) of the sheet P, the movable guide 71 can be stably operated to reduce or eliminate the interrupted portion SP of the junction guide member 10A. Therefore, the sheet P can smoothly pass through the junction G, and the stabilization of the sheet conveyance at the junction G can be realized. This is particularly effective when a curved conveying path is configured in which the traveling direction is changed by a predetermined angle or more between the one conveying path (L2) and the conveying path (L3) after the junction of the multiple conveying paths (L1, L2). The same applies to the embodiment 2-3 described later.

[0055] Specifically, the movable guide operating portion 700 is configured to swing the movable guide 71 around the swing axis so as to approach or contact the transfer guide member 10C in conjunction with the rotation of the transport roller 11. This makes it possible, with a simple configuration, to make it difficult for resistance to be applied to the sheet P transported to one transport path (L2) when the sheet P passes through the junction G, and to reduce or eliminate the discontinuous portion SP of the junction guide member 10A, thereby stabilizing the sheet transport.

[0056] In this embodiment, the movable guide 71 includes a pressing member 72 and a biasing member 74 .

[0057] In this example, the roller support 70 is provided with regulating portions 701 and 702 (in this example, the tip of the top plate 70a of the roller support 70 and the tip of the bottom plate 70b of the sheet conveying device main body 10a) for regulating the swing of the movable guide 71 around the swing axis of the swing shaft 73 within a predetermined swing range. Here, the predetermined swing range is a swing range from the original first position (position before swing) of the movable guide 71 to a second position where the tip of the movable guide 71 contacts or approaches the transfer guide member 10C. The regulating portion 701 regulates the movable guide 71 from rotating too far from the first position. The regulating portion 702 regulates the movable guide 71 from rotating too far from the second position. By providing these regulating portions (701 and 702), the sheet P to be conveyed to the sheet supply path L1 can be reliably conveyed to the sheet conveying path L3 when the movable guide 71 is located at the first position. When the movable guide 71 is located at the second position, the sheet P conveyed to the reversing conveying path L2 can be reliably conveyed to the sheet conveying path L3.

[0058] The main body 711 of the movable guide 71 is formed in a slope such that its vertical width gradually decreases from the upstream side to the downstream side in the sheet transport direction H, and a roughly rectangular recess 714 that opens toward the end of the rotating shaft 13 is formed from the center to the upstream end.

[0059] The pressing member 72 is arranged so that one end is connected to the rotating shaft 13 via a torque limiter 715 and the other end is inserted into a recess 714 of an end plate 713 .

[0060] The biasing member 74 biases the movable guide 71 in a first swing direction W1 opposite to the transfer guide member 10C in the swing direction W of the movable guide 71. That is, the biasing member 74 biases the pressing member 72 so that the movable guide 71 moves toward the first position. This allows the movable guide 71 to be positioned at the first position when the rotating shaft 13 is not rotating.

[0061] According to this configuration, as shown in FIG. 5B, when the sheet P heading toward the junction G from one conveying path (L2) passes through the conveying roller 11, the movable guide 71 can be swung in the second swing direction W2 toward the transit guide member 10C side in the swing direction W relative to the roller support 70 by the pressing member 72 in the movable guide operating part 700 in conjunction with the rotation of the conveying roller 11. As a result, the movable guide 71 can be positioned at the second position, that is, can be brought close to or into contact with the transit guide member 10C side. Therefore, the sheet P can be smoothly passed through the junction G. On the other hand, as shown in FIG. 5A, after the sheet P passes through the junction G, the movable guide 71 can be moved away from the transit guide member 10C by the action of the biasing member 74 and returned to the original first position. As a result, a passage for the sheet P entering the junction G from the other conveying path (L1) can be secured. The conveying roller 11 rotates constantly during an image formation (printing) job and stops after the rear end of the sheet P being conveyed (the last sheet P to be conveyed in the case of performing continuous image forming operations) passes through the junction G.

[0062] Specifically, the urging member 74 is a kick spring, and with a spring main body inserted into the attachment portion 721, one end is engaged with the pressing member 72 and the other end is anchored to the upper plate 70a of the roller support body 70. The pressing member 72 includes an attachment portion 721 attached to an end of the rotating shaft 13 via a torque limiter 715, and a contact portion 722 formed integrally with the attachment portion 721 and extending from the attachment portion 721 along the radial direction of the rotating shaft 13.

[0063] Torque limiter 715 includes inner ring 715a and outer ring 715b that slides against inner ring 715a while receiving a predetermined frictional resistance. With this, in torque limiter 715, when the load on outer ring 715b is equal to or less than a reference load, outer ring 715b rotates in conjunction with the rotation of inner ring 715a, but when the load on outer ring 715b exceeds the reference load, outer ring 715b does not rotate even if inner ring 715a rotates.

[0064] An attachment portion 721 of the pressing member 72 is fixed to an outer ring 715b of the torque limiter 715, and an end of the rotating shaft 13 is fixed to an inner ring 715a of the torque limiter 715. As a result, the torque limiter 715 is configured such that, when the rotating shaft 13 is rotating, if the load on the pressing member 72 is equal to or less than a reference load, the pressing member 72 rotates together with the rotating shaft 13, and if the load on the pressing member 72 exceeds the reference load, the pressing member 72 does not rotate even if the rotating shaft 13 rotates.

[0065] When the rotating shaft 13 rotates in the rotation direction F1, the contact portion 722 of the pressing member 72 comes into contact with the lower portion 714a of the recessed portion 714, and when the pressing member 72 rotates further, the movable guide 71 moves from the first position to the second position against the biasing force of the biasing member 74 (see FIG. 5B). When the rotating shaft 13 stops rotating, the contact of the contact portion 722 with the lower portion 714a of the recessed portion 714 is released by the biasing force of the biasing member 74, and the movable guide 71 returns from the second position to the first position (see FIG. 5A).

[0066] As described above, in this embodiment, when there is no sheet P entering the junction G from one conveying path (reverse conveying path L2), i.e., when the rotating shaft 13 is not rotating in the rotation direction F1, as shown in FIG. 5A, a space (discontinuous part SP) is secured between the tip of the movable guide 71 and the transfer guide member 10C, and the sheet P conveyed to the sheet supply path L1 passes through this space (SP) and heads toward the pre-registration roller 52 along the transfer guide member 10C, as shown by the dotted arrow.

[0067] On the other hand, when the sheet P enters the junction G from the reverse conveying path L2, that is, when the rotating shaft 13 rotates in the rotation direction F1, as shown in FIG. 5B, when the pressing member 72 rotates in the rotation direction F1 around the rotation axis of the rotating shaft 13 in conjunction with the rotation of the rotating shaft 13 by a predetermined angle, the tip of the abutting portion 722 presses the movable guide 71 downward against the biasing force of the biasing member 74. The pressed movable guide 71 swings in the rotation direction F1 around the swing axis of the swing shaft 73 to be located at the second position, and its tip comes into contact with or approaches (in this example, approaches) the transfer guide member 10C. As a result, the space (SP) between the tip of the movable guide 71 and the transfer guide member 10C can be eliminated or reduced (reduced in this example), and the movable guide 71 and the transfer guide member 10C can be connected or almost connected (almost connected in this example). This allows the sheet P conveyed to the reversing conveying path L2 to smoothly pass through the junction G as indicated by the dotted arrow.

[0068] After the sheet P conveyed to the reversing conveying path L2 passes through the junction G, the rotation of the rotating shaft 13 stops. Then, the rotation torque in the rotation direction F1 applied to the pressing member 72 disappears, and the pressing member 72 returns to its original position by the action of the biasing member 74. In response to this, the movable guide 71 swings in a direction away from the transfer guide member 10C and returns to the first position shown in FIG. 5A. Then, the sheet P conveyed to the sheet supply path L1 can reliably pass through the space (SP) between the tip of the movable guide 71 and the transfer guide member 10C while suppressing the interference of the sheet P moving from the upstream side of the sheet supply path L1 toward the junction G with the movable guide 71.

[0069] <Embodiment 2> The second embodiment of the present disclosure differs from the first embodiment described above only in the structures of the movable guide 81 and the movable guide action portion 800, so next, the movable guide 81 and the movable guide action portion 800 will be mainly described.

[0070] 6A and 6B are cross-sectional views that show schematic views of a peripheral structure of the junction G in another example of the sheet conveying device 10 of the present embodiment. Fig. 6A shows a state in which the rotating shaft 13 is not rotating and the movable guide 81 is not operating, and Fig. 6B shows a state in which the rotating shaft 13 is rotating and the movable guide 81 is operating.

[0071] The sheet transporting device 10 according to this embodiment is configured such that a movable guide 81 shown in FIGS. 6A and 6B is provided on a junction guide member 10A in the basic configuration of the sheet transporting device 10 shown in FIG.

[0072] Specifically, the movable guide 81 is installed at a position upstream of the junction G, and is configured to move in a movement direction M along the sheet conveying direction H relative to the junction guide member 10A. The movable guide operating unit 800 is configured to move the movable guide 81 in the movement direction M in conjunction with the rotation of the conveying roller 11 so as to approach or contact (in this example, contact) the transfer guide member 10C to which the sheet P passing through the junction G from the first conveying path (L2) will transfer. This makes it possible to make it difficult for resistance to be applied to the sheet P conveyed to the first conveying path (L2) when the sheet P passes through the junction G, despite the simple configuration, and to reduce or eliminate the interrupted portion SP of the junction guide member 10A, thereby stabilizing the sheet conveyance.

[0073] In this example, the movable guide 81 is installed in the junction guide member 10A. The roller support 70 is provided with regulating portions 84a and 84b that regulate the movement of the movable guide 81 along the movement direction M within a predetermined movement range. Here, the predetermined movement range is the movement range from the original first position of the movable guide 81 (the position before movement) to the second position where the tip of the movable guide 81 contacts or is close to the transfer guide member 10C. The regulating portion 84a regulates the movable guide 81 from moving too far out of the first position. The regulating portion 84b regulates the movable guide 81 from moving too far out of the second position.

[0074] The movable guide operation unit 800 includes a drive transmission mechanism 82 and an urging member 83. The drive transmission mechanism 82 has a drive input side connected to the rotating shaft 13 of the conveying roller 11 via a torque limiter 715, and a drive output side connected to the movable guide 81. The urging member 83 urges the movable guide 81 toward the second moving direction M2 opposite to the transit guide member 10C in the moving direction M. This allows the movable guide 81 to be positioned at the first position when the rotating shaft 13 is not rotating. The drive transmission mechanism 82 converts the rotational drive from the conveying roller 11 into a moving drive in the first moving direction M1 toward the transit guide member 10C in the moving direction M, and transmits it to the movable guide 81.

[0075] According to this configuration, as shown in FIG. 6B, when the sheet P heading toward the junction G from one conveying path (L2) passes through the conveying roller 11, the movable guide 81 can be moved in the second moving direction M2 toward the transit guide member 10C side in the moving direction M relative to the roller support 70 by the drive transmission mechanism 82 in the movable guide operating part 800 in conjunction with the rotation of the conveying roller 11. This allows the movable guide 81 to be moved to the second position, that is, to approach or contact the transit guide member 10C side. Therefore, the sheet P can be smoothly passed through the junction G. On the other hand, as shown in FIG. 6A, after the sheet P passes through the junction G, the movable guide 81 can be separated from the transit guide member 10C by the action of the biasing member 83 and returned to the original first position. This allows a passage for the sheet P entering the junction G from the other conveying path (L1).

[0076] Specifically, the movable guide 81 includes an expandable piece 81a that can move from the lower portion of the junction guide member 10A toward the transfer guide member 10C, and a support portion 81b that supports the expandable piece 81a. The expandable piece 81a is a thin plate-like member made of a film material or the like. The drive transmission mechanism 82 uses the rotational driving force of the conveying roller 11 to move the expandable piece 81a in a moving direction M along the sheet conveying direction H relative to the junction guide member 10A.

[0077] The drive transmission mechanism 82 includes a rack gear 82 a , a drive gear 82 b , a driven gear 82 c , and a biasing member 83 .

[0078] The rack gear 82a is provided at the upper end of the support portion 81b of the movable guide 81. The drive gear 82b is connected to the rotation shaft 13 of the conveying roller 11 via a torque limiter 715. The driven gear 82c meshes with the drive gear 82b and also meshes with the rack gear 82a. In this example, the urging member 83 is a coil spring, one end of which is connected to the roller support 70 and the other end of which is connected to the upstream end of the support portion 81b.

[0079] The drive gear 82b, the driven gear 82c and the rack gear 82a are configured to convert the rotational drive from the rotating shaft 13 of the conveying roller 11 into a movement drive in the second movement direction M2 toward the transfer guide member 10C in the movement direction M, and transmit it to the movable guide 81.

[0080] In this example, the junction guide member 10A of the roller support 70 is provided with restricting portions 84a and 84b for restricting the movement of the movable guide 81 along the movement direction M to a predetermined movement range. Here, the predetermined movement range is a distance range from the original first position (position before movement) of the movable guide 81 to a second position immediately before the tip contacts the transit guide member 10C. By providing the restricting portions 84a and 84b, it is possible to prevent the movable guide 81 from colliding with the transit guide member 10C, and it is also possible to effectively prevent the movable guide 81 from being retracted too far by the biasing member 83.

[0081] The torque limiter 715 is the same as that used in the first embodiment, and a description thereof will be omitted here.

[0082] The drive gear 82b of the drive transmission mechanism 82 is fixed to an outer ring 715b of the torque limiter 715, and an end of the rotating shaft 13 is fixed to an inner ring 715a of the torque limiter 715. The torque limiter 715 is configured such that, when the rotating shaft 13 is rotating, if the load on the drive gear 82b is equal to or less than a reference load, the drive gear 82b rotates together with the rotating shaft 13, and if the load on the drive gear 82b exceeds the reference load, the drive gear 82b does not rotate even if the rotating shaft 13 rotates.

[0083] When the rotating shaft 13 rotates in the rotation direction F1 and the driving gear 82b is driven to rotate in the rotation direction F1, the driven gear 82c is driven to rotate in the reverse rotation direction F2 opposite to the rotation direction F1. Then, the rack gear 82a, i.e., the movable guide 81 moves from the first position to the second position in the first moving direction M1 on the transfer guide member 10C side in the moving direction M against the biasing force of the biasing member 83 (see FIG. 6B). When the rotation of the rotating shaft 13 stops, the driving rotation of the driving gear 82b is released, and the movable guide 81 returns from the second position to the first position by the biasing force of the biasing member 83 (see FIG. 6A).

[0084] As described above, in this embodiment, when there is no sheet P entering the junction G from one conveying path (reverse conveying path L2), that is, when the rotating shaft 13 is not rotating in the rotation direction F1, the tip end (extendable piece 81a) of the movable guide 81 is retracted to the bottom of the junction guide member 10A as shown in Fig. 6A. In this case, a space (SP) is secured between the tip end (extendable piece 81a) of the movable guide 81 and the transit guide member 10C, and the sheet P conveyed to the sheet supply path L1 passes through this space (SP) and heads toward the pre-registration roller 52 along the transit guide member 10C.

[0085] On the other hand, when the sheet P enters the junction G from the reverse conveying path L2, that is, when the rotating shaft 13 rotates in the rotation direction F1, as shown in FIG. 6B, in the drive transmission mechanism 82, the drive gear 82b rotates in the rotation direction F1 by a predetermined angle in conjunction with the rotation of the rotating shaft 13, and rotates the driven gear 82c in the opposite direction to the rotation direction F1. At this time, the movable guide 81 moves from the lower part of the junction guide member 10A to the second movement direction M2 on the transfer guide member 10C side in the movement direction M against the biasing force of the biasing member 83 together with the rack gear 82a, and stops at a position where it contacts or almost contacts (contacts in this example) with the transfer guide member 10C. As a result, the space (SP) between the tip of the movable guide 81 and the transfer guide member 10C can be closed or almost closed (closed in this example), and the movable guide 81 and the transfer guide member 10C can be connected or almost connected. That is, at the junction G, the discontinuous portion SP of the junction guide member 10A can be eliminated or almost eliminated, and the sheet P transported to the reverse transport path L2 can smoothly pass through the junction G. The transport roller 11 rotates all the time during an image formation (printing) job, and stops after the rear end of the transported sheet P (the last sheet P transported in the case of performing continuous image formation operations) passes through the junction G.

[0086] After the sheet P conveyed to the reversing conveying path L2 passes through the junction G, the rotation of the rotating shaft 13 stops, and the rotational torque in the rotation direction F1 that the end of the rotating shaft 13 applies to the drive gear 82b disappears, and the movable guide 81 moves in a direction away from the transfer guide member 10C by the action of the biasing member 83, and returns to the first return position shown in Fig. 6A. In this way, the sheet P conveyed to the sheet supply path L1 can reliably pass through the space (SP) between the tip of the movable guide 81 and the transfer guide member 10C while suppressing interference with the movable guide 81 by the sheet P moving from the upstream side of the sheet supply path L1 toward the junction G.

[0087] <Embodiment 3> The third embodiment of the present disclosure differs from the first embodiment described above only in the structures of the movable guide 91 and the movable guide action portion 900, and therefore next, the movable guide 91 and the movable guide action portion 900 will be mainly described.

[0088] 7A and 7B are cross-sectional views that show a schematic structure of the junction G in yet another example of the sheet transport device 10 of the present embodiment. Fig. 7A shows a state in which the sheet P has not yet reached the transport rollers 11 and the movable guide 91 is not in operation, and Fig. 7B shows a state in which the sheet P has reached the transport rollers 11 and the movable guide 91 is in operation.

[0089] FIG. 8 is a block diagram showing an example of a system configuration of the movable guide operating unit 900 in the sheet conveying device 10 according to the present embodiment.

[0090] The sheet transporting device 10 according to this embodiment is configured such that the transfer guide member 10C in the basic configuration of the sheet transporting device 10 shown in FIG. 2 acts as the movable guide 91 shown in FIGS. 7A and 7B.

[0091] In detail, the movable guide 91 is installed at a position downstream of the junction G, and is configured to rotate about a rotation axis perpendicular to the sheet conveying direction H and along the surface of the sheet P relative to the sheet conveying device main body 10a. The movable guide operating unit 900 is configured to operate the movable guide 91 so that the sheet P approaches or comes into contact with the junction guide member 10A (in this example, contact) when the sheet P reaches the conveying roller 11. This makes it possible to make it difficult for resistance to be applied to the sheet P conveyed to one conveying path (L2) when the sheet P passes through the junction G, even with a simple configuration, and to reduce or eliminate the interrupted portion SP of the junction guide member 10A, thereby stabilizing the sheet conveyance.

[0092] In this embodiment, the movable guide 91 is installed as a transfer guide member 10C for a sheet P passing through the junction G from one conveying path (L2). The sheet conveying device main body 10a is provided with regulating parts 96a and 96b that regulate the rotation of the movable guide 91 around the rotation axis within a predetermined rotation range. Here, the predetermined rotation range is a rotation range from the original first position (position before rotation) of the movable guide 91 to a second position where the tip of the movable guide 91 contacts or is close to the junction guide member 10A. The regulating part 96a regulates the movable guide 91 from rotating too far from the first position. The regulating part 96b regulates the movable guide 91 from rotating too far from the second position.

[0093] The movable guide operating unit 900 includes a biasing member 92 , a driving unit 93 , a detection unit 94 , and a control unit 95 .

[0094] The biasing member 92 biases the movable guide 91 in a first rotation direction R1 opposite to the junction guide member 10A in the rotation direction R of the movable guide 91. The drive unit 93 rotates the movable guide 91 in a second rotation direction R2 toward the junction guide member 10A side. The detection unit 94 detects that the sheet P has reached the conveying roller 11 (that is, that the sheet P has reached the upstream side of the conveying roller 11 (specifically, the upstream side vicinity)). The control unit 95 operates the drive unit 93 when the detection unit 94 detects that the sheet P has reached the conveying roller 11. Here, rotation refers to a rotation of 360 degrees or more, and rotation refers to a rotation of less than 360 degrees.

[0095] According to this configuration, when the control unit 95 detects that the sheet P heading toward the junction G from one conveying path (L2) has reached the conveying roller 11 by the detection signal of the detection unit 94 (in this example, when the detection signal is received by the detection unit 94), it operates the drive unit 93 to rotate the movable guide 91, which is the transfer guide member 10C, so as to approach or contact (in this example, contact) the roller support 70 against the biasing force of the biasing member 92. This allows the sheet P to pass smoothly through the junction G. On the other hand, after detecting that the sheet P has passed through the junction G (in this example, after a predetermined time has elapsed since the detection signal by the detection unit 94 disappeared), the control unit 95 can cancel the operation of the drive unit 93 and return the movable guide 91 to the original first position by the action of the biasing member 92. This allows a passage for the sheet P entering the junction G from the other conveying path (L1).

[0096] Specifically, the movable guide 91 has a cross section formed into an approximate right-angled triangle, and is supported rotatably about an axis of a pivot shaft 97 (support shaft) perpendicular to the sheet conveying direction H and along the surface of the sheet P with respect to the sheet conveying device main body 10a (device main body 1a). The surface of the movable guide 91 facing the upper guide member 10B extends toward the pre-registration roller 52 while gently curving from the downstream side to the upstream side of the junction guide member 10A along the sheet conveying direction H. The movable guide 91 guides the sheet P transferring from the junction guide member 10A toward the pre-registration roller 52.

[0097] The rotation shaft 97 is installed in the sheet conveying device main body 10a via a support member (not shown), and supports the movable guide 91 so that the movable guide 91 is rotatable.

[0098] In this example, the biasing member 92 is a coil spring, one end of which is connected to the upstream end of the movable guide 91 and the other end of which is connected to the sheet conveying device main body 10a so that the upstream end of the movable guide 91 is separated from the junction guide member 10A. This allows the movable guide 91 to be positioned in the original first position.

[0099] In this example, the driving unit 93 is an electromagnetic solenoid, and is connected to the downstream end of the movable guide 91 as shown in FIGS. 7A and 7B.

[0100] 8, the driving unit 93 is electrically connected to an output system of the control unit 95. This allows the control unit 95 to control the on (energization) / off (energization stop) of the driving unit 93 based on a signal received from the detection unit 94.

[0101] The control unit 95 has a processing unit (not shown) made up of a computer such as a CPU (Central Processing Unit), and a storage unit (not shown) including a non-volatile memory such as a ROM (Read Only Memory) and a volatile memory such as a RAM (Random Access Memory). The control unit 95 controls the operation of various components by the processing unit loading a control program stored in advance in the ROM of the storage unit onto the RAM of the storage unit and executing it. The control unit 95 may be controlled by a main control unit of the image forming apparatus 1.

[0102] When the drive unit 93 is turned on by a command signal from the control unit 95, the movable guide 91 rotates in the second rotation direction R2 against the biasing force of the biasing member 92. As a result, as shown in FIG. 7B, the movable guide 91 can be positioned at the second position and the upstream end of the movable guide 91 can approach or contact (in this example, contact) the junction guide member 10A. On the other hand, when the drive unit 93 is turned off by a command signal from the control unit 95, the movable guide 91 rotates in the first rotation direction R1 by the biasing force of the biasing member 92. As a result, as shown in FIG. 7A, the movable guide 91 can be positioned at the first position and the upstream end of the movable guide 91 can be separated from the junction guide member 10A.

[0103] The detection unit 94 detects the presence or absence of the sheet P being conveyed, and is installed in the vicinity of the upstream side of the conveying roller 11. In this example, the detection unit 94 is composed of an actuator that swings due to the conveying force of the sheet P, and a transmission type optical sensor that is turned on / off by the swinging of the actuator.

[0104] The detection unit 94 is electrically connected to an input system of the control unit 95. This enables the control unit 95 to detect that the sheet P reaches the conveying rollers 11.

[0105] FIG. 9 is a flowchart showing an example of a process performed by the control unit 95 of the movable guide operating unit 900 in the sheet conveying device 10 according to the present embodiment.

[0106] 9, when there is no sheet P entering the junction G from one conveying path (reverse conveying path L2), the detection unit 94 does not detect a detection signal, and therefore the control unit 95 determines in step S1 that it has not received a detection signal from the detection unit 94, and waits as is. In this case, as shown in FIG. 7A, a space (SP) is secured between the upstream end of the movable guide 91 and the tip of the junction guide member 10A, and the sheet P conveyed from the upstream side of the other conveying path (sheet supply path L1) can pass through this space (SP) and move toward the pre-registration roller 52 along the movable guide 91.

[0107] On the other hand, when the sheet P enters the junction G from one conveying path (L2), when the detection unit 94 detects that the sheet P reaches the conveying roller 11, the control unit 95 determines in step S1 that it has received a detection signal from the detection unit 94, and proceeds to step S2. In step S2, the control unit 95 outputs an ON signal to the drive unit 93 to drive the drive unit 93. When the drive unit 93 is driven, the plunger is attracted to the electromagnet. Then, as shown in FIG. 7B, the movable guide 91 rotates in a second rotation direction R2 in the rotation direction R and is located at the second position. As a result, the upstream end of the movable guide 91 comes into contact with or is close to (in this example, in contact with) the tip of the junction guide member 10A. As a result, the space (SP) between the upstream end of the movable guide 91 and the tip of the junction guide member 10A can be closed or nearly closed, and this makes it possible to connect or nearly connect the upstream end of the movable guide 91 to the tip of the junction guide member 10A. In other words, it is possible to almost completely eliminate the disconnected portion SP of the junction guide member 10A at the junction G, and the sheet P conveyed to the reverse conveying path L2 can smoothly pass through the junction G.

[0108] In step S3, the control unit 95 judges whether or not the detection signal from the detection unit 94 has been received, and if the detection signal has been received, the process returns to step S2, and the driving state of the drive unit 93 continues. On the other hand, when the sheet P entering the junction G from the reverse conveyance path L2 side disappears and the detection signal from the detection unit 94 stops, the control unit 95 proceeds to step S4, and after a predetermined time has elapsed since the control unit 95 detected the rear end of the sheet P, in step S5, the control unit 95 outputs an OFF signal to the drive unit 93 to stop driving the drive unit 93, and returns to the standby state.

[0109] When the drive unit 93 is deactivated, the electromagnetic force acting on the plunger is eliminated by the biasing force of the biasing member 92, and therefore the tension pulling the downstream end of the movable guide 91 is eliminated. Then, as shown in Fig. 7A, the movable guide 91 is pulled by the biasing force of the biasing member 92 to rotate in the first rotation direction R1 in the rotation direction R, and returns to the original first position. As a result, as shown in Fig. 8A, the sheet P conveyed to the sheet supply path L1 can reliably pass through the space (SP) between the tip of the movable guide 81 and the transfer guide member 10C while suppressing interference with the movable guide 81 by the sheet P moving from the upstream side of the sheet supply path L1 toward the junction G.

[0110] The above-described embodiments are illustrative in all respects and are not intended to be limiting. Therefore, the technical scope of the present disclosure is not interpreted solely by the above-described embodiments, but is defined based on the claims. Also, all modifications within the scope and meaning equivalent to the claims are included. [Industrial Applicability]

[0111] The present disclosure can achieve stabilization of sheet transport at a junction where multiple transport paths join, and is therefore applicable to sheet transport devices and image forming devices equipped with the same, such as copiers, multifunction devices, printers, and facsimile machines. [Explanation of symbols]

[0112] 1. Image forming device 10 Sheet transport device 10a Sheet conveying device body 11 Transport roller 12 Driven roller 13 Rotation axis 1a Device body G confluence 10A Junction guide member 10B Upper guide member 10C Transfer guide material 70 Roller support 700 Movable guide operating part 701 Regulatory Department 702 Regulatory Department 70a Top plate 70b bottom plate 71 Movable guide 711 Main body 712 Guide Rib 713 End plate 714 Recess 715 Torque limiter 715a Inner circle 715b Outer ring 72 Pressing member 721 Mounting part 722 Contact part 73 Swing Axis 74 Pressing member 800 Movable guide operating part 81 Movable guide 81a Telescopic piece 81b Support part 82 Drive transmission mechanism 82a Rack gear 82b Drive gear 82c Driven gear 83 Pressing member 84a Regulatory Department 84b Regulatory Department 900 Movable guide operating part 91 Movable guide 92 Pressing member 93 Drive unit 94 Detection unit 95 Control Unit 96a Regulatory Department 96b Regulatory Department F1 Rotation direction F2 Reverse rotation direction H Sheet transport direction K Swing axis direction L1 Sheet supply path (an example of another transport path) L2 Reversing conveying path (an example of one conveying path) L3 Sheet transport path (an example of a transport path after merging) M Movement direction M1 1st movement direction M2 2nd movement direction P-sheet R Rotation direction R1 1st rotation direction R2 Second rotation direction SP Interrupted part W Swing direction W1 First swing direction W2 Second oscillation direction

Claims

1. A sheet conveying device including a plurality of conveying paths for conveying a sheet, at least two of the plurality of conveying paths joining together at a joining portion, a movable guide that moves toward a portion where a guide of a guide member that configures one of the at least two transport paths at the junction is discontinued; a movable guide operating unit that operates the movable guide in response to the operation of a conveying roller that conveys the sheet from the first conveying path to the junction, so as to reduce or eliminate any interruptions in the guide when the sheet enters the junction from the first conveying path.

2. 2. The sheet transport device according to claim 1, wherein the first transport path and the transport path resulting from the merging of the plurality of transport paths form a curved transport path in which a travel direction is changed by at least a predetermined angle.

3. the movable guide is installed at a position upstream of the junction, and is configured to swing about a swing axis perpendicular to the sheet conveying direction and along the sheet surface with respect to a roller support to which the conveying roller is attached, The sheet conveying device of claim 1, characterized in that the movable guide operating portion is configured to oscillate the movable guide around the oscillating axis in conjunction with the rotation of the conveying roller so that the sheet passing through the junction from the one conveying path approaches or contacts a transfer guide member to which the sheet will transfer.

4. the movable guide is provided as a guide member that constitutes the one transport path at the junction, The sheet conveying device of claim 3, characterized in that the movable guide operating portion comprises a pressing member having one end connected to the rotating shaft of the conveying roller via a torque limiter and the other end pressing the movable guide toward the transfer guide member, and a biasing member biasing the movable guide toward the opposite side to the transfer guide member in the swinging direction of the movable guide.

5. the movable guide is disposed at a position upstream of the junction and configured to move in a moving direction along a sheet conveying direction relative to a guide member constituting the one conveying path at the junction, The sheet transport device of claim 1, characterized in that the movable guide operating portion is configured to move the movable guide in the moving direction in conjunction with the rotation of the transport roller so as to approach or contact a transfer guide member through which a sheet passing through the junction from the one transport path transfers.

6. The movable guide is installed in a guide member located upstream of the junction, the movable guide operation unit includes a drive transmission mechanism having a drive input side connected to a rotation shaft of the conveying roller via a torque limiter and a drive output side connected to the movable guide, and a biasing member that biases the movable guide toward an opposite side to the transfer guide member in the movement direction, 6. The sheet transport device according to claim 5, wherein the drive transmission mechanism converts the rotational drive from the transport roller into a moving drive toward the transfer guide member in the moving direction and transmits the moving drive to the movable guide.

7. the movable guide is disposed at a position downstream of the junction and configured to rotate about a rotation axis perpendicular to a sheet conveying direction and along a sheet surface with respect to a sheet conveying device body; 2. The sheet transport device according to claim 1, characterized in that, when the sheet reaches the transport roller, the movable guide operating portion operates the movable guide so that the sheet approaches or comes into contact with a guide member that constitutes the one transport path at the junction.

8. The movable guide is installed as a transfer guide member through which a sheet passing through the junction portion from the first conveying path transfers, The sheet transport device of claim 7, characterized in that the movable guide operating unit includes a biasing member that biases the movable guide in the direction of rotation toward the opposite side to the guide member that constitutes the first transport path at the junction, a drive unit that rotates the movable guide toward the guide member that constitutes the first transport path at the junction, a detection unit that detects that the sheet has reached the transport roller, and a control unit that operates the drive unit when the detection unit detects that the sheet has reached the transport roller.

9. 9. An image forming apparatus comprising the sheet conveying device according to claim 1.

Images