JP2006056672A - Paper guiding device of image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control the attitude of a movable guide without applying a load on paper sheets and installing parts requiring electrical control at a position where two paper carrying routes are converged or branched. <P>SOLUTION: This paper guiding device 70 is installed at the position where a paper carrying passage 20 for carrying paper sheets as a first paper carrying passage is converged to a paper carrying passage 60 for double printing as a second paper carrying passage. A movable guide 71 holds a first attitude supporting the carriage of the paper sheets P passing a paper carrying passage 20 for always passing paper sheets by the action of a tension spring 74. When the paper sheets P passes through the paper carrying passage 60 for double printing, a torsional coiled spring 72 as a clutch element fitted to the shaft part 62a of a carrying roller 62 is rotated according to the carrying roller 62 by the its connecting action with the shaft part 62a by friction. In connection with this rotation, a lever part 73 fitted to the torsional coiled spring 72 changes the attitude of the movable guide 71 to a second attitude for supporting the carriage of the paper sheets P passed through the paper carrying passage 60 for double printing. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sheet guide device for an image forming apparatus represented by a copying machine or a printer.

  In an image forming apparatus such as a copying machine or a printer, components such as a sheet feeding unit, a transfer unit, a fixing unit, and a sheet reversing unit for duplex printing are arranged, and a sheet conveyance path is formed between them. ing. In such an image forming apparatus, when the paper feed unit includes a plurality of stages of paper cassettes, the paper conveyance paths continuing from the respective paper cassettes merge at a certain location to form a single paper conveyance path. To the transfer section for transferring the toner image.

  In addition, some image forming apparatuses having a duplex printing function employ a switchback method in the paper reversing unit to switch the paper transport direction. From the paper transport path to this paper reversing unit, from the paper reversing unit The subsequent paper transport path is branched. The paper conveyance path continuing from the paper reversing unit joins the paper conveyance path between the paper feeding unit and the transfer unit.

As described above, a movable guide is provided at a location where the two paper conveyance paths merge or branch to assist the conveyance of the paper through the two paper conveyance paths. Examples of such a sheet guide device of an image forming apparatus can be seen in Patent Documents 1 and 2.
JP 10-218455 A (page 3-4, FIG. 2) JP 2002-274747 A (page 4-6, FIG. 2)

  In the paper reversing device (paper guiding device) described in Patent Document 1, in the paper reversing unit for performing double-sided printing, the paper conveyance path leading to the reversing unit joins the paper conveyance path continuing from the reversing unit. In addition, a branching claw (movable guide) that is displaced by being pushed and moved by the driving force of the paper is provided at this location. However, with this paper reversing device, the branch claw is displaced by pressing the leading edge of the paper conveyed to the reversing section against the branch claw, so that the paper is burdened, wrinkled, torn, or This can cause paper jams.

  The double-sided paper feeder (paper guide device) described in Patent Document 2 includes a reversing switching claw (movable guide) that is displaced using a solenoid in a paper reversing unit similar to that of Patent Document 1 described above. However, in this double-sided sheet feeding device, a solenoid is used to displace the reversing switching claw, so that there are problems that the cost is increased, the space for installing the solenoid is secured, and electrical control is required.

  The present invention has been made in view of the above points, and places a burden on a sheet at a place where two sheet conveyance paths merge or branch, or is expensive like a solenoid and requires electrical control. It is an object of the present invention to provide a paper guide device for an image forming apparatus that can control the posture of a movable guide without attaching parts and can smoothly transport paper.

  In order to solve the above-described problems, the present invention is provided at a location where the first paper transport path and the second paper transport path merge or branch, and transports the paper through these two paper transport paths. In order to assist, a movable guide that can be changed in posture is provided, and this movable guide always maintains a first posture for assisting conveyance of the sheet passing through the first sheet conveyance path, When the paper is transported through the second paper transport path, the second posture assists the transport of the paper through the second paper transport path in conjunction with the rotation of the transport roller provided in the second paper transport path. The posture was changed.

  Further, in the paper guide device of the image forming apparatus having the above-described configuration, a connecting action with the shaft portion is provided when the transport roller rotates in the paper feed direction and is provided on the shaft portion of the transport roller of the second paper transport path. A clutch element, a lever portion that is attached to the clutch element and engages with the movable guide to change the posture of the movable guide to the second posture, and a bias that biases the movable guide to the first posture Means.

  Further, the clutch element is constituted by a torsion coil spring.

  Further, the clutch element is composed of a torque limiter.

  According to the configuration of the present invention, the movable guide provided at the location where the first paper transport path and the second paper transport path merge or branch is always in contact with the paper passing through the first paper transport path. The first posture for assisting the conveyance is maintained, and when conveying the sheet through the second sheet conveyance path, the first posture is interlocked with the rotation of the conveyance roller provided in the second sheet conveyance path. Since the posture is changed to the second posture that assists the conveyance of the paper passing through the second paper conveyance path, only when the paper passes through the second paper conveyance path by using the rotating force of the conveyance roller. The movable guide can be changed in posture to the second posture. Thereby, the posture of the movable guide can be controlled without imposing a burden on the paper or using an electric component such as a solenoid. Therefore, it is possible to smoothly convey the sheet even when the sheet passes through any of the sheet conveying paths at the place where the two sheet conveying paths merge or branch.

  Further, a clutch element is provided at the shaft portion of the transport roller of the second paper transport path, and causes a coupling action with the shaft portion when the transport roller rotates in the paper feed direction, and is attached to the clutch element and is attached to the movable guide. Since the lever portion that engages and changes the posture of the movable guide to the second posture and the urging means that urges the movable guide to the first posture are provided, the second paper transport path is set to the paper. When the clutch passes, the clutch element rotates in accordance with the rotation of the conveying roller, and the movable guide can be changed to the second attitude by using the rotational force of the clutch element. Further, when the conveying roller is not rotating, the connecting action between the shaft portion and the clutch element does not occur, so that the movable guide can be automatically changed to the first posture by the urging means. Therefore, with such a simple mechanism, the posture of the movable guide can be freely controlled in response to the sheet passing through one of the two sheet conveyance paths.

  In addition, since the clutch element is configured by a torsion coil spring, the rotational force of the transport roller can be used with a simpler configuration in order to change the posture of the movable guide. Therefore, it is possible to provide a paper guide device that can further smoothly reduce the cost by using the torsion coil spring and can smoothly transport the paper.

  In addition, since the clutch element is constituted by a torque limiter, as in the case of the torsion coil spring, in order to change the posture of the movable guide, the rotational force of the conveying roller can be used with a simpler configuration. Can do. Therefore, it is possible to provide a paper guide device that can further reduce the cost by using the torque limiter and can smoothly transport the paper.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  First, an outline of the structure of an image forming apparatus using a paper guide apparatus according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a left side view of a schematic vertical section showing a schematic structure of a printer as an example of an image forming apparatus. In FIG. 1, the right side is the front side of the printer, and the left side is the back side.

  As shown in FIG. 1, a paper feeding unit 10 is disposed below the inside of the main body 2 of the printer 1. The paper supply unit 10 includes a paper cassette 11 and a paper supply device 12. In the paper supply unit 10, the paper cassette 11 is provided in two upper and lower stages, and a paper supply device 12 is provided for each of them. Inside the paper cassette 11, paper P is stacked and stored. The paper feeding device 12 is disposed above the downstream portion of the paper cassette 11 in the paper conveyance direction, and feeds the paper P toward the upper right of the paper cassette 11 in FIG. The paper cassette 11 can be pulled out horizontally from the front side of the main body 2, that is, from the right side in FIG.

  A paper feed path 20, a transport roller 3, a registration roller 4, an image forming unit 30, and a transfer unit 40 are disposed downstream of the paper feed unit 10 in the paper transport direction. The image forming unit 30 includes a photosensitive drum 31 as an image carrier at the center thereof. An optical unit 5 is provided above the image forming unit 30, and a laser beam L is emitted from the optical unit 5 toward the photosensitive drum 31. A one-dot chain line in the figure indicates the laser beam L. The transfer unit 40 includes a transfer roller 41 as a transfer member. The transfer roller 41 is pressed against the photosensitive drum 31 from below, and forms a transfer nip portion for transferring the toner image onto the paper P.

  A fixing unit 6, a discharge paper transport path 7, and a paper discharge unit 50 are disposed downstream of the image forming unit 30 and the transfer unit 40 in the paper transport direction. The paper discharge unit 50 includes a discharge roller 51 and a paper receiving tray 52. The paper receiving tray 52 is provided on the upper surface of the main body 2 at a position where the printed paper P can be taken out from the outside.

  A double-sided printing paper conveyance path 60 is disposed below the fixing unit 6 and the transfer unit 40 and between the paper feeding unit 10. The double-sided printing paper conveyance path 60 branches off from the middle of the discharge paper conveyance path 7 and joins the paper supply paper conveyance path 20 immediately before the conveyance roller 3. A paper guiding device 70 is disposed at a location where the paper feeding paper conveyance path 20 and the double-sided printing paper conveyance path 60 merge.

  The printer 1 having the above configuration performs a printing operation as follows.

  The paper P before printing is stored in a stacked state in the paper cassette 11 of the paper supply unit 10, and is fed one by one by the paper supply device 12 from here. The fed paper P is delivered to the transport roller 3 through the paper feed paper transport path 20 and reaches the registration roller 4. The registration roller 4 corrects the oblique feeding of the paper P, measures the timing with the toner image formed by the image forming unit 30, and sends the paper P to the transfer unit 40.

  Image data signals such as characters, graphics, and patterns from an external computer (not shown) are transmitted to the printer 1, and laser light L controlled by the optical unit 5 is irradiated based on the image data. As a result, an electrostatic latent image of the original image is formed on the photosensitive drum 31 in the image forming unit 30, and a toner image is formed on the photosensitive drum 31 from the electrostatic latent image. The toner image is transferred to the paper P sent in synchronization by the registration roller 4 at a transfer nip portion formed by press contact between the photosensitive drum 31 and the transfer roller 41 of the transfer portion 40.

  Thereafter, the paper P carrying the unfixed toner image is sent to the fixing unit 6 and the toner image is fixed by the heat roller. The paper P discharged from the fixing unit 6 is sent upward through the paper transport path 7 for discharge, and is discharged onto a paper receiving tray 52 provided on the upper surface of the main body 2 by a discharge roller 51 of the paper discharge unit 50. Is done.

  Here, the discharge roller 51 that discharges the paper P toward the paper receiving tray 52 also has a function of switching back the paper P in order to perform double-sided printing. When performing duplex printing, the transport direction of the paper P discharged from the fixing unit 6 is switched at the position of the discharge roller 51. Then, the paper P is sent to the double-sided printing paper conveyance path 60, joined by the paper guide device 70 to the paper feeding paper conveyance path 20, and sent again to the transfer unit 40.

  Next, a detailed configuration around the sheet guide device 70 according to the first embodiment of the present invention will be described with reference to FIGS. 2 and 3 in addition to FIG. FIG. 2 is a partially enlarged schematic vertical section showing the periphery of the sheet guide device, and FIG. 3 is a schematic perspective view of the same.

  As described above, the paper guide device 70 is disposed at a location where the paper feeding paper conveyance path 20 that is the first paper conveyance path and the double-sided printing paper conveyance path 60 that is the second paper conveyance path merge. Has been. The paper guide device 70 includes a movable guide 71, a torsion coil spring 72 that is a clutch element, a lever portion 73, and a tension spring 74 that is a biasing means.

  The movable guide 71 is provided between the paper feeding paper conveyance path 20 and the double-sided printing paper conveyance path 60 to be merged, and the inner guide 21 of the paper feeding paper conveyance path 20 and the double-sided printing paper conveyance path 60. It is located on an extension line of the lower guide 61. The inner guide 21 and the lower guide 61 are fixed guides fixed to the main body 2. The movable guide 71 includes a curved guide portion 71a having substantially the same length as that of the paper feeding paper conveyance path 20 and the double-sided printing paper conveyance path 60 in the paper width direction perpendicular to the paper conveyance direction. Side plates 71b are provided at both ends of the guide portion 71a. The side plate 71b is provided with a support shaft 71c protruding in the horizontal direction, and the movable guide 71 is supported by the main body 2 by the support shaft 71c. The movable guide 71 can be changed in posture to assist the conveyance of the paper P passing through the two paper conveyance paths by rotating in the vertical plane around the support shaft 71c. FIG. 2 shows a state in which the movable guide 71 is in a first posture that assists the conveyance of the paper P passing through the paper feeding paper conveyance path 20 that is the first paper conveyance path.

  The torsion coil spring 72 is provided so that the shaft portion 62a of the transport roller 62 provided in the double-sided printing paper transport path 60 passes through the inside of the coil. The inner diameter of the coil of the torsion coil spring 72 is slightly smaller than the outer diameter of the shaft portion 62 a of the transport roller 62, and the coil portion of the torsion coil spring 72 fastens the shaft portion 62 a of the transport roller 62.

  A lever portion 73 is attached to one end of the torsion coil spring 72. The lever portion 73 is configured by linearly extending one end of the torsion coil spring 72. The distal end of the lever portion 73 is engaged with an engagement piece 71d provided on one side plate 71b of the movable guide 71 from below the engagement piece 71d. The tip of the lever portion 73 is bent at a right angle so that it can be easily engaged with the engagement piece 71d.

  The tension spring 74 is attached between the engagement piece 71 d of the movable guide 71 and the main body 2. The tension spring 74 is constituted by a coil spring, and is an urging means that constantly urges the movable guide 71 to the first posture shown in FIG. Since the upper end portion of the movable guide 71 contacts the upper guide 63 of the double-sided printing paper conveyance path 60 fixed to the main body 2, the movable guide 71 rotates counterclockwise beyond the position shown in FIG. Never do.

  Next, the guidance operation of the paper P by the paper guidance device 70 will be described with reference to FIG. 4 in addition to FIG. FIG. 4 is a model vertical cross-sectional partial enlarged view showing the periphery of the sheet guide device similar to FIG. 2, and shows a state in which the movable guide is in the second posture.

  In the printer 1, when the paper P is fed from the paper cassette 11 (see FIG. 1) of the paper feeding unit 10 by the paper feeding device 12, the movable guide 71 of the paper guiding device 70 is shown in FIG. In the first position. Accordingly, the paper P is transported so as to be guided by the surface of the guide 71a of the movable guide 71 on the side of the paper feeding paper transport path 20 and the outer guide 22 of the paper feeding paper transport path 20. It passes through the path 20 and reaches the position of the conveyance roller 3 (arrow A in FIG. 2). While the normal sheet supply operation is performed, the movable guide 71 always maintains the first posture.

  When the printer 1 receives a double-sided printing command from an external computer, the paper P after fixing is switched back by the discharge roller 51 and sent to the paper conveyance path 60 for double-sided printing. As a result, in the double-sided printing paper conveyance path 60, as shown in FIG. 4, the conveyance roller 62 is rotated in the paper feeding direction, that is, counterclockwise by the driving means (not shown) to convey the paper P (arrow in FIG. 4). B). At this time, due to the friction between the inner surface of the coil portion of the torsion coil spring 72 and the outer surface of the shaft portion 62a of the transport roller 62, the torsion coil spring 72 is connected to the shaft portion 62a. According to the rotation of the conveying roller 62, it rotates counterclockwise in FIG.

  When the torsion coil spring 72 rotates in accordance with the conveying roller 62, the lever portion 73 is displaced upward in FIG. 4 in conjunction with this (arrow C in FIG. 4). Thereby, the engaging piece 71d of the movable guide 71 is lifted (same arrow D), and the movable guide 71 rotates clockwise (same arrow E), and double-sided printing which is the second paper conveyance path shown in FIG. The posture is changed to the second posture that assists the conveyance of the paper P passing through the paper conveyance path 60. Accordingly, the sheet P is transported on the duplex printing sheet so that the sheet P is guided by the surface of the guide portion 71a of the movable guide 71 on the duplex transport sheet transport path 60 side and the upper guide 63 of the duplex transport sheet transport path 60. It passes through the path 60 and reaches the position of the transport roller 3 (arrow F).

  Note that the tension spring 74 that constantly biases the movable guide 71 to the first posture does not hinder the lever 71 from lifting the engagement piece 71 and the movable guide 71 from changing the posture to the second posture. Has elasticity.

  Further, the movable guide 71 does not rotate clockwise beyond the position shown in FIG. 4 due to the action of a stopper (not shown). At this time, since the conveyance roller 62 continues to rotate, the torsion coil spring 72 is twisted in the expansion direction due to friction between the shaft portion 62 a of the conveyance roller 62 and the coil portion of the torsion coil spring 72. As a result, the tightening of the torsion coil spring 72 at the shaft portion 62 a of the transport roller 62 becomes loose, the shaft portion 62 a of the transport roller 62 slides inside the coil of the torsion coil spring 72, and the transport roller 62 and the torsion coil spring 72 The connection is released. Therefore, even if the transport roller 62 continues to rotate to transport the paper P, the transport roller 62 and its driving means are not adversely affected.

  When the paper P passes through the paper transport path 60 for double-sided printing, the transport roller 62 is disconnected from its driving means. As a result, the transport roller 62 is unconstrained and can freely rotate. Thus, a coupling action occurs between the shaft portion 62 a and the torsion coil spring 72, and at the same time, the lever portion 73 engages with the movable guide 71. The force to lift the combined piece 71d is also weakened. As a result, the movable guide 71 returns to the first posture by the action of the tension spring 74.

  In this way, the movable guide 71 provided at the location where the paper feeding paper conveyance path 20 as the first paper conveyance path and the double-sided printing paper conveyance path 60 as the second paper conveyance path merge. The first posture for assisting the conveyance of the paper P through the paper feeding paper conveyance path 20 is always maintained. When the paper P is conveyed through the double-sided printing paper conveyance path 60, the double-sided printing paper In conjunction with the rotation of the transport roller 62 provided in the transport path 60, the posture is changed to the second posture that assists the transport of the paper P passing through the paper transport path 60 for double-sided printing, so the transport roller 62 rotates. Using the force, the movable guide 71 can be changed to the second posture only when the paper P passes through the double-sided printing paper conveyance path 60. Thus, the posture of the movable guide 71 can be controlled without imposing a burden on the paper P or using an electric component such as a solenoid. Accordingly, the paper P can be smoothly transported at the location where the two paper transport paths meet, regardless of which paper transport path passes through the paper P.

  Also, a clutch that is provided on the shaft portion 62a of the transport roller 62 of the double-sided printing paper transport path 60, which is the second paper transport path, and generates a coupling action with the shaft portion 62a when the transport roller 62 rotates in the paper feed direction. An element, a lever portion 73 that is attached to the clutch element and engages with the movable guide 71 to change the posture of the movable guide 71 to the second posture; and a bias that biases the movable guide 71 to the first posture. When the sheet P passes through the double-sided printing paper conveyance path 60, the clutch element rotates according to the rotation of the conveyance roller 62, and the movable guide 71 uses the rotational force of the clutch element. Can be changed to the second posture. Further, when the conveying roller 62 is not rotating, the coupling action between the shaft portion 62a and the clutch element does not occur, so that the movable guide 71 can be automatically changed to the first posture by the tension spring 74. . Therefore, with such a simple mechanism, the posture of the movable guide 71 can be freely controlled in response to the sheet P passing through one of the two sheet conveyance paths.

  And since the said clutch element is comprised by the torsion coil spring 72, in order to change the attitude | position of the movable guide 71, the rotational force of the conveyance roller 62 can be utilized with a simpler structure. Therefore, it is possible to provide a paper guide device 70 that can further smoothly reduce the cost by using the torsion coil spring 72 and can smoothly transport the paper P.

  Next, a detailed configuration around the sheet guiding apparatus 70 according to the second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a schematic perspective view showing the periphery of the sheet guide device. Since the basic configuration of this embodiment is the same as that of the first embodiment shown in FIGS. 1 to 4, the same components as those of the first embodiment are denoted by the same reference numerals as before, The description will be omitted.

  In the second embodiment, the clutch element provided in the paper guide device 70 is constituted by a torque limiter 75. The torque limiter 75 is disposed between the shaft portion 62a of the transport roller 62 and a lever member 76 attached to the shaft portion 62a so as to coincide with the axis. The lever portion 77 of the lever member 76 extends toward the movable guide 71, and has an engagement pin 78 that engages with an engagement piece 71 d of the movable guide 71 from below at the tip thereof.

  In the printer 1 equipped with the paper guide device 70 configured as described above, when the paper P is fed into the paper transport path 60 for double-sided printing, the transport roller 62 moves in the paper feed direction to transport the paper P as shown in FIG. It rotates (arrow G in FIG. 5). At this time, the torque applied to the lever member 76 does not exceed the set torque of the torque limiter 75, and the lever member 76 rotates in the same direction according to the rotation of the conveying roller 62. Displace upward (same arrow H). As a result, the engaging piece 71d of the movable guide 71 is lifted (same arrow J), and the movable guide 71 rotates (same arrow K), and passes through the double-sided printing paper conveyance path 60, which is the second paper conveyance path. The posture is changed to the second posture that assists the conveyance of P (see FIG. 4).

  When the movable guide 71 changes its posture to the second posture, it does not rotate any more due to the action of a stopper (not shown). Therefore, the lever member 76 is applied with a torque greater than the set torque of the torque limiter 75, and the lever member 76 Stops rotating. At this time, the transport roller 62 continues to rotate to transport the paper P, but the transport roller 62 and its driving means are not adversely affected by the action of the torque limiter 75.

  When the paper P passes through the paper transport path 60 for double-sided printing, the transport roller 62 is disconnected from its driving means. As a result, the transport roller 62 and the lever member 76 are released from the restraint and can freely rotate. Therefore, the force by which the lever portion 77 lifts the engaging piece 71d of the movable guide 71 is weakened, and the action of the tension spring 74 The movable guide 71 returns to the first posture.

  In this way, since the clutch element of the paper guiding device 70 is configured by the torque limiter 75, in order to change the posture of the movable guide 71 as in the case of the torsion coil spring 72 in the first embodiment, The rotational force of the transport roller 62 can be used with a simpler configuration. Therefore, it is possible to provide a paper guide device 70 that can further reduce the cost by using the torque limiter 75 and can smoothly transport the paper P.

  The tension spring 74 that constantly biases the movable guide 71 to the first posture is not limited to a coil spring, but biasing means for other springs such as leaf springs and elastic members such as rubber and sponge. You may use as.

  Further, in the present embodiment, an example in which the paper guide device 70 of the present invention is applied to a location where the paper feeding paper conveyance path 20 and the double-sided printing paper conveyance path 60 merge is shown. In the case where a plurality of stages are provided, the sheet guide device 70 is applied to a location (X portion in FIG. 1) where the sheet conveyance path continuing from the lower sheet cassette 11 and the sheet conveyance path continuing from the upper sheet cassette 11 merge. It doesn't matter. Similarly, the paper guide device 70 may be applied to a portion (Y portion in FIG. 1) where the duplex paper transport path 60 branches from the discharge paper transport path 7.

  Although the embodiments of the present invention have been described above, the scope of the present invention is not limited to these embodiments, and various modifications can be made without departing from the spirit of the invention.

  The present invention can be used in all image forming apparatuses in which two paper conveyance paths are joined or branched.

1 is a schematic vertical cross-sectional left side view showing a schematic structure of a printer using a paper guide device according to a first embodiment of the present invention. FIG. 2 is a partially enlarged view of a schematic vertical section showing the periphery of the sheet guide device in FIG. 1. It is a model perspective view which shows the paper guide apparatus periphery of FIG. FIG. 3 is a schematic vertical sectional partial enlarged view showing the periphery of the sheet guide device similar to FIG. 2, showing a state where the movable guide is in the second posture. It is a model perspective view which shows the paper guide apparatus periphery which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

1 Printer (image forming device)
2 Main body 7 Discharge paper transport path 10 Paper feed section 11 Paper cassette 20 Paper feed paper transport path (first paper transport path)
21 Inner guide 50 Paper discharge portion 51 Discharge roller 60 Paper transport path for double-sided printing (second paper transport path)
61 Lower Guide 62 Conveying Roller 63 Upper Guide 62a Shaft Part 70 Paper Guide Device 71 Movable Guide 71a Guide Part 71c Spindle 71d Engagement Piece 72 Torsion Coil Spring (Clutch Element)
73 Lever part 74 Tension spring (biasing means)
75 Torque limiter (clutch element)
76 Lever member 77 Lever part

Claims (4)

  A movable guide that is provided at a location where the first paper transport path and the second paper transport path merge or branch, and whose posture can be changed to assist the transport of the paper through the two paper transport paths. The movable guide always maintains a first posture for assisting conveyance of the sheet passing through the first sheet conveyance path, and when conveying the sheet through the second sheet conveyance path, An image forming apparatus characterized in that the posture is changed to a second posture that assists the conveyance of the sheet passing through the second sheet conveyance path in conjunction with the rotation of the conveyance roller provided in the second sheet conveyance path. Paper guide device.   A clutch element that is provided at a shaft portion of the transport roller of the second paper transport path, and causes a coupling action with the shaft portion when the transport roller rotates in the paper feed direction; 2. A lever portion that engages the first guide member to change the posture of the movable guide to the second posture, and biasing means that biases the movable guide to the first posture. A sheet guide device for the image forming apparatus.   The sheet guide device for an image forming apparatus according to claim 2, wherein the clutch element includes a torsion coil spring.   The sheet guide device for an image forming apparatus according to claim 2, wherein the clutch element includes a torque limiter.

Images