JP2017013954A - Sheet discharging device and image forming device comprising the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet discharging device that can prevent a rear end of a sheet member from getting caught when the sheet member is discharged through a sheet discharge port, with a simple structure, and an image forming device comprising the same.SOLUTION: A print sheet discharged from a sheet discharge port of an image forming device is supported on a sheet discharge tray. The sheet discharge tray has a wall part 82, and closer to inside of the device than the wall part 82 are provided a displacing member 90 and a driving transmission mechanism 100. The driving transmission mechanism 100 transmits rotation driving force from a driven roller 25B to the displacing member 90 so as to reciprocate the displacing member 90. The displacing member 90 has a protruding part 92. The protruding part 92 appears and disappears through an opening 83 of the wall part 82 according to movement of the displacing member 90.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a sheet discharge apparatus including a sheet support portion that supports a sheet member discharged after image formation, and an image forming apparatus including the sheet discharge apparatus.

  2. Description of the Related Art Conventionally, image forming apparatuses such as copiers and printers are provided with a sheet discharge device for discharging a sheet member such as a printing sheet on which an image is formed to the outside. The sheet member discharged from the sheet discharge port by the sheet discharge device is held in a sheet tray provided below the sheet discharge port. When a plurality of sheet members are discharged, a plurality of printing sheets are stacked on the sheet tray so as to be stacked in the vertical direction. In such a sheet tray, the rear end of the stacked sheet member may be caught at the joint between the sheet discharge port and the side wall of the sheet tray, and the sheet member may not be stacked correctly. For such a stacking failure, Patent Document 1 discloses a mechanism that improves the stackability of documents by blowing an airflow to the trailing edge of the document.

JP 2004-43131 A

  However, the conventional mechanism described in the above-mentioned patent document requires a mechanism for blowing an air current, which not only makes the structure complicated, but also causes a problem of increasing the cost due to an increase in the number of parts.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to discharge a sheet that can prevent the trailing edge of the sheet member from being caught when the sheet member is discharged from the sheet discharge port with a simple configuration. An apparatus and an image forming apparatus including the same are provided.

  A sheet discharge device according to one aspect of the present invention includes a discharge portion, a sheet support portion, a wall portion, a displacement member, and a drive transmission portion. The discharge unit includes a rotating body that discharges the sheet member to the outside from the sheet discharge port by being rotated in a predetermined positive rotation direction. The sheet support part supports the sheet member discharged from the sheet discharge port. The wall portion extends upward from an end portion of the sheet support portion on the sheet discharge port side toward the sheet discharge port. The displacement member is provided on the inner side of the apparatus with respect to the wall portion, and is buried inside the first position and the outer surface that protrude outward from the outer surface of the wall portion through an opening formed in the wall portion. It can be displaced between the second position. The drive transmission unit operates in conjunction with the rotation of the rotating body in the positive rotation direction, and transmits a driving force for displacing the displacement member between the first position and the second position to the displacement member. To do.

  An image forming apparatus according to another aspect of the present invention includes the sheet discharge device.

  According to the present invention, it is possible to prevent the rear end of the sheet member from being caught when the sheet member is discharged from the sheet discharge port.

FIG. 1 is a diagram illustrating an image forming apparatus according to a first embodiment of the present invention. FIG. 2 is a diagram showing an internal configuration of the image forming apparatus shown in FIG. FIG. 3 is a cross-sectional view showing a peripheral configuration of the sheet discharge device provided in the image forming apparatus of FIG. FIG. 4 is a diagram illustrating a driving mechanism that drives a displacement member included in the sheet discharging apparatus. FIG. 5 is a diagram illustrating an operation state of the displacement member by the drive transmission mechanism of the sheet discharging apparatus. FIG. 6 is a diagram illustrating an operation state of the displacement member by the drive transmission mechanism of the sheet discharging apparatus. FIG. 7 is a diagram illustrating the displacement members disposed at the first position and the second position. FIG. 8 is a diagram showing a second embodiment of the present invention. FIG. 9 is a diagram illustrating a third embodiment of the present invention, and is a diagram illustrating a blocking unit that blocks driving transmission to a displacement member included in the sheet discharge device. FIG. 10 is a diagram illustrating the fourth embodiment of the present invention, and is a diagram illustrating another configuration example of the displacement member and the drive transmission mechanism of the sheet discharging apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The following embodiments are examples embodying the present invention, and do not limit the technical scope of the present invention.

[First Embodiment]
Hereinafter, with reference to the drawings, in each drawing, the image forming apparatus 10 is installed on a flat surface (the state shown in FIG. 1), and the image forming apparatus 10 has a vertical direction 6, a front-rear direction 7, and a horizontal direction. 8 is defined. An image forming apparatus 10 according to a first embodiment of the invention will be described.

  First, the configuration of the image forming apparatus 10 will be described with reference to FIGS. 1 and 2. As shown in FIG. 1, the image forming apparatus 10 is a so-called in-body discharge type multifunction peripheral, and includes various functions such as a printer, a copier, a FAX apparatus, and a scanner. The image forming apparatus 10 forms an image of the input image on a printing paper P (an example of a sheet member of the present invention) using a printing material such as toner. Note that the image forming apparatus 10 is not limited to a multifunction peripheral, and the present invention can be applied to a printer, a copier, a FAX apparatus, or the like.

  The image forming apparatus 10 includes an image reading unit 12, an image forming unit 14, and a paper discharge unit 30 (an example of a sheet discharge device of the present invention). The image reading unit 12 is provided on the upper part of the image forming apparatus 10. The image reading unit 12 performs processing for reading an image of a document. The image forming unit 14 is provided in the lower part of the image forming apparatus 10. The image forming unit 14 performs a process of forming an image based on the electrophotographic method. The image forming unit 14 includes two paper feeding devices 27 and 28 arranged in two upper and lower stages. The upper sheet feeder 27 is provided integrally with the housing 29 at the lowermost part of the image forming unit 14. The lower sheet feeding device 28 is of an extension type connected as an optional device to the bottom surface of the casing 29 of the image forming unit 14. A paper discharge unit 30 is provided on the right side of the image forming unit 14. The image forming unit 14 is not limited to an electrophotographic type, and may be an inkjet recording type, or may be a recording method or printing method other than that.

  A paper discharge space 21 for discharging the printing paper P is provided above the image forming unit 14. The paper discharge unit 30 is provided so as to connect the image forming unit 14 and the image reading unit 12 while forming a paper discharge space 21 between the image forming unit 14 and the image reading unit 12. As shown in FIG. 1, the front side and the left side of the paper discharge space 21 are open. Further, the rear side and the right side of the paper discharge space 21 are not opened, the rear side is closed, and a paper discharge unit 30 is provided on the right side. A paper discharge tray 80 that holds the discharged print paper P is provided in the paper discharge space 21. The paper discharge tray 80 will be described later.

  As shown in FIG. 2, the image reading unit 12 includes a document cover 24 and an ADF 13. When the image forming apparatus 10 functions as a copying machine, the image reading unit 12 reads image data of a document set on the document table 23 (see FIG. 1) or a document conveyed by the ADF 13. Then, the read image data is sent to the image forming unit 14. In FIG. 1, illustration of the document cover 24 of the image reading unit 12 is omitted.

  The image forming unit 14 forms an image on the printing paper P based on the image data read by the image reading unit 12 or image data input from the outside. The image forming unit 14 performs single-sided printing processing (single-sided image forming processing) for forming an image only on one side of the printing paper P or printing paper according to a preset printing mode (single-sided printing mode or double-sided printing mode). One of double-sided printing processing (double-sided image forming processing) for forming images on both sides of P is performed.

  When the single-sided printing process is performed, the image forming unit 14 discharges the printing paper P on which an image is formed on one side to the paper discharge tray 80 in the paper discharge space 21. On the other hand, when the double-sided printing process is performed, the image forming unit 14 switches back the printing paper P on which the image is formed on one side, sends it to the reverse conveyance path 39, conveys it again to the image forming position, and then reverses. An image is formed on the side surface. Thereafter, the printing paper P on which images are formed on both sides is discharged to the paper discharge tray 80 in the paper discharge space 21. The reverse conveyance path 39 is a conveyance path that branches from a branch point T1 in the middle of a discharge path 26A described later and reaches the junction T2 of the vertical conveyance path 26.

  As shown in FIG. 2, the image forming apparatus 10 mainly includes sheet feeding devices 27 and 28, an image transfer unit 18, a fixing unit 19, a discharge roller pair 25 (an example of a discharge unit of the present invention), and a discharge tray 80. (An example of the sheet support unit of the present invention), a drive transmission mechanism 100 (an example of the drive transmission unit of the present invention), a control unit (not shown) that controls the image forming apparatus 10 in an integrated manner, and the like. The paper feeding devices 27 and 28, the image transfer unit 18, and the fixing unit 19 are provided in the image forming unit 14. The paper discharge tray 80 and the drive transmission mechanism 100 are provided in the paper discharge unit 30. Further, the image forming apparatus 10 includes a transport motor and a discharge motor (both not shown). These are provided inside a casing 29 that constitutes an outer frame cover, an inner frame, and the like of the image forming unit 14 and the paper discharge unit 30.

  The sheet feeding devices 27 and 28 convey the sheet member toward the image transfer unit 18. Each of the paper feeding devices 27 and 28 includes a tray-shaped paper container 22 and a paper feeding mechanism 15. Printing paper P on which an image is formed by the image transfer unit 18 is stacked on the paper storage unit 22. The paper feed mechanism 15 takes out the printing paper P stored in the paper storage unit 22 one by one and transports it to the vertical transport path 26.

  As shown in FIG. 2, in the image forming unit 14, a vertical conveyance path 26 is formed upward from the paper feeding mechanism 15 of the paper feeding device 27. The vertical conveyance path 26 is formed on the right side surface inside the housing 29 and extends in the up-down direction 6 along the right side surface. The vertical conveyance path 26 is formed in a section that reaches a sheet discharge port 37 (an example of a sheet discharge port of the present invention) via a junction point T2, a transfer roller 35, a fixing unit 19, and a branch point T1, which will be described later. The printing paper P that has passed through the fixing unit 19 passes through the vertical conveyance path 26 and is discharged to the outside from the paper discharge port 37.

  In the housing 29, a reverse conveyance path 39 is formed on the right side of the vertical conveyance path 26. The reverse conveyance path 39 is a conveyance path that branches from the branch point T1 of the vertical conveyance path 26 and merges again with the vertical conveyance path 26 at the junction T2. Here, the branch point T <b> 1 is a portion where the conveyance path is branched from the outlet on the downstream side of the fixing unit 19 described later in the vertical conveyance path 26 to the reverse conveyance path 39. Further, the junction point T <b> 2 is a portion where the reverse conveyance path 39 joins the vertical conveyance path 26 on the upstream side of the image transfer unit 18 described later in the vertical conveyance path 26.

  An image transfer unit 18 is provided above the paper feeding device 27. The image transfer unit 18 performs an image transfer process on the printing paper P conveyed through the vertical conveyance path 26. Specifically, the image transfer unit 18 transfers the toner image to the printing paper P using a printing material such as toner based on the input image data. As shown in FIG. 3, the image transfer unit 18 includes a photosensitive drum 31, a charging unit 32, a developing unit 33, an LSU (Laser Scanning Unit) 34, a transfer roller 35, and a cleaning unit 36. ing. When the printing paper P passes through the nip portion between the transfer roller 35 and the photosensitive drum 31, the toner image is transferred to the printing paper P by the transfer roller 35. The printing paper P onto which the toner image has been transferred is conveyed to a fixing unit 19 disposed downstream (that is, on the upper side) in the conveying direction of the printing paper P with respect to the image transfer unit 18.

  The fixing unit 19 fixes the toner image transferred to the printing paper P onto the printing paper P by heat. The fixing unit 19 includes a heating roller 41 and a pressure roller 42. The heating roller 41 is heated to a high temperature by a heating device 41A (see FIG. 3) such as a heater during the fixing operation. When the printing paper P passes through the fixing unit 19, the toner is heated and melted by the heating roller 41, and the printing paper P is pressurized by the pressure roller 42. As a result, the toner image is fixed on the printing paper P, and an image is formed on the printing paper P. The fixed printing paper P is conveyed from the fixing unit 19 toward a later-described paper discharge port 37 by the rollers 41 and 42 of the fixing unit 19.

  As shown in FIG. 2, a paper discharge port 37 through which the printing paper P is discharged is formed at the end of the vertical conveyance path 26. Hereinafter, for convenience of explanation, a path from the outlet on the downstream side of the fixing unit 19 to the sheet discharge port 37 in the vertical conveyance path 26 is referred to as a discharge path 26A. That is, the paper discharge port 37 is formed at the end of the discharge path 26A. The paper discharge port 37 is provided on the left side surface 30 </ b> A of the paper discharge unit 30 that forms the side surface of the housing 29. The sheet discharge port 37 is an opening that is elongated in the width direction (a direction that coincides with the front-rear direction 7 in FIG. 1). The left side surface 30 </ b> A of the paper discharge unit 30 is a vertical surface extending in the vertical direction 6. The paper discharge port 37 is exposed to the paper discharge space 21 from the left side surface 30A.

  The discharge path 26 </ b> A is a conveyance path for guiding the printing paper P on which the image is fixed by the fixing unit 19 to the paper discharge port 37. The discharge path 26A is formed in a curved shape that extends upward in the vertical direction from the fixing unit 19 and then curves toward the paper discharge port 37 in the vicinity of the branch point T1 on the way. The discharge path 26A is formed by a plurality of conveyance guides 62 to 65 (see FIG. 3). The conveyance guides 62 and 63 are provided along a straight path from the fixing unit 19 to the branch point T1 in the discharge path 26A (see FIG. 2). The conveyance guides 64 and 65 are provided along the curved path from the branch point T1 to the sheet discharge port 37 in the discharge path 26A. In the present embodiment, the end of the sheet discharge port 37 in the vertical direction 6 is formed by the end of the conveyance guides 64 and 65. In addition, an accommodation portion 64 </ b> A that accommodates a driven roller 25 </ b> B described later is formed at the end portion of the conveyance guide 64.

  The discharge roller pair 25 is provided in the vicinity of the paper discharge port 37. The discharge roller pair 25 discharges the printing paper P from the paper discharge port 37 to the external paper discharge tray 80 by rotating in a predetermined later-described normal rotation direction. The discharge roller pair 25 is a pair of rollers configured by a driving roller 25A and a driven roller 25B (an example of the rotating body of the present invention) that are pressed against each other.

  The drive roller 25 </ b> A is pivotally supported by the conveyance guide 65. Bidirectional rotational driving force from the discharging motor (not shown) is transmitted to the driving roller 25A. For this reason, the driving roller 25 </ b> A can rotate in the rotation direction according to the input rotational driving force.

  The driven roller 25 </ b> B is pivotally supported by the conveyance guide 64. The driven roller 25 </ b> B is pivotally supported in a state of being housed in a housing portion 64 </ b> A formed at the terminal portion of the conveyance guide 64. The driven roller 25B is urged toward the driving roller 25A by an elastic member (not shown) such as a coil spring. Thereby, the driven roller 25B is always pressed against the surface of the driving roller 25A with an appropriate elastic biasing force. Therefore, when the driving roller 25A is rotationally driven, the driven roller 25B is also driven by contact friction.

  Here, in the present embodiment, the following forward rotation direction and reverse rotation direction are defined as the rotation directions of the driving roller 25A and the driven roller 25B. That is, the positive rotation direction is a direction in which the printing paper P is rotated when the printing paper P is discharged by the discharge roller pair 25. In addition, the reverse rotation direction is a rotation direction opposite to the normal rotation direction, and is a direction rotated when the printing paper P is transported in the reverse transport direction returning to the reverse transport path 39 during duplex printing. .

  Also, as shown in FIG. 4, two discharge roller pairs 25 are provided along the width direction of the paper discharge port 37 at a predetermined interval. In FIG. 4, the drive roller 25A is indicated by a two-dot chain line.

  By controlling the rotation direction of the discharge motor (not shown), the two discharge roller pairs 25 print in either the discharge direction toward the discharge space 21 or the reverse feed direction toward a branch point T1 described later. The paper P is conveyed. For example, the printing paper P passing through the fixing unit 19 and transported to the discharge path 26A is transported in the discharge direction by the discharge roller pair 25 rotated in the normal rotation direction by the discharge motor. Further, the printing paper P is conveyed in the reverse feed direction by the discharge roller pair 25 rotated in the reverse rotation direction by the discharge motor.

  As shown in FIGS. 2 and 3, the paper discharge tray 80 supports the print paper P discharged from the paper discharge port 37. The paper discharge tray 80 is provided below the paper discharge port 37 in the paper discharge space 21. Therefore, the print paper P discharged from the paper discharge port 37 falls downward due to its own weight in the process of being discharged and is supported by the paper discharge tray 80. The paper discharge tray 80 is configured as a separate member from the casing 29 and the paper discharge unit 30. The paper discharge tray 80 is attached to the housing 29, the paper discharge unit 30, and the like with a fixing tool such as a screw.

  As shown in FIG. 3, the paper discharge tray 80 includes a support portion 81 that forms a support surface for supporting the printing paper P, and an end portion 86 (right end portion on the paper discharge port 37 side) of the support portion 81. ) And a wall 82 extending upward along the left side surface 30A. The support portion 81 is formed in a tray shape, and supports and stacks the printing paper P on the support surface 81A on the upper surface thereof. The support surface 81A of the support portion 81 is gently inclined downward on the paper discharge port 37 side. And the wall part 82 is formed so that it may continue upwards from the edge part 86 of the inclination direction. The upper end 82A of the wall portion 82 reaches the bottom surface 64B of the accommodating portion 64A.

  An opening 83 is formed in the wall portion 82. The opening 83 is formed on the upper end side of the wall portion 82, and specifically, is a narrow notch groove cut downward from the upper end 82 </ b> A of the wall portion 82. Three openings 83 are formed in the wall portion 82. One opening 83 is formed in the center of the wall portion 82 in the width direction (front-rear direction 7), and the other two openings 83 are outward from the center of the wall portion 82 in the width direction (front-rear direction 7). They are formed at positions that are equally spaced apart. Each opening 83 is a portion through which a protrusion 92 of a displacement member 90 described later is inserted.

  Three slits 85 are formed on the left side surface 30 </ b> A of the paper discharge unit 30. Each slit 85 is formed at a position corresponding to the opening 83. The upper end of the slit 85 reaches the bottom surface 64B of the accommodating portion 64A. Therefore, a through space by the opening 83 and the slit 85 is formed between the paper discharge space 21 and the inside of the paper discharge unit 30.

  As shown in FIGS. 3 and 4, a displacement member 90 is provided inside the paper discharge unit 30. The displacement member 90 is provided on the inner side than the left side surface 30A. In other words, the displacement member 90 is provided on the inner side of the paper discharge unit 30 than the wall portion 82. In the present embodiment, the displacement member 90 is disposed in the vicinity of the left side surface 30A, and a first position (position shown in FIGS. 5C and 7B) and a second position (FIG. A) and a position shown in FIG.

  The displacement member 90 has a receiving portion 91 that receives a driving force from a drive transmission mechanism 100 described later. The receiving portion 91 is a plate member that extends in the vertical direction 6 inside the paper discharge portion 30. The receiving portion 91 is provided inside the paper discharge portion 30 so as to face the left side surface 30A. The upper end of the receiving portion 91 reaches the vicinity of the bottom surface 64B of the accommodating portion 64A. Further, the receiving portion 91 extends in the front-rear direction 7. Support shafts 93 are provided at both ends of the receiving portion 91 in the front-rear direction 7. The support shaft 93 is movably supported in a guide groove extending in the left-right direction 8 formed in a frame (not shown) of the paper discharge unit 30, whereby the displacement member 90 is movable in the left-right direction 8.

  Further, the displacement member 90 has three protrusions 92 that are inserted through the slits 85 and the openings 83. The protruding portion 92 is formed integrally with the receiving portion 91. The protruding portion 92 is a left side surface of the receiving portion 91 and is provided on the facing surface 91A that faces the left side surface 30A. More specifically, the protruding portion 92 is provided on the upper end of the facing surface 91A. The protruding portion 92 protrudes leftward from the facing surface 91A. An inclined surface 92 </ b> A is formed at the end of each protruding portion 92 in the protruding direction, and is inclined toward the upper left side. Each protrusion 92 is disposed at a position corresponding to the slit 85 and the opening 83, and is exposed to the paper discharge space 21 from the slit 85 and the opening 83 according to the movement position of the displacement member 90. In the present embodiment, the displacement member 90 is supported by the support shaft 93 so as to be movable between the first position and the second position. The first position is a position where the protruding portion 92 protrudes from the outer surface of the wall portion 82 through the slit 85 and the opening 83 toward the discharge space 21 (that is, the outer side) (see FIGS. 5C and 7B). It is. The second position is a position where the protruding portion 92 is buried inside the wall portion 82 (see FIGS. 5A and 7A). The movement of the displacement member 90 is realized by supplying a driving force by a drive transmission mechanism 100 described later.

  As shown in FIGS. 4 and 5, the drive transmission mechanism 100 is provided inside the paper discharge unit 30. The drive transmission mechanism 100 is provided on each of the front side and the rear side in the front-rear direction 7, and is provided at a position deviated from the transport path of the printing paper P to the front side and the rear side in the discharge path 26A. In FIG. 4, only the drive transmission mechanism 100 on the front side is shown, and the illustration of the drive transmission mechanism 100 on the rear side is omitted. The drive transmission mechanism 100 operates in conjunction with the rotation of the driven roller 25B in the forward rotation direction, and transmits a driving force that moves the displacement member 90 between the first position and the second position to the displacement member 90. To do. The drive transmission mechanism 100 converts the rotational motion of the driven roller 25 </ b> B in the positive rotational direction into a linear motion in the left-right direction 8, and transmits the rotational driving force of the driven roller 25 </ b> B to the displacement member 90.

  As shown in FIG. 5, the drive transmission mechanism 100 includes an input gear 101, intermediate gears 102 to 104, an output gear 105 (an example of the transmission gear of the present invention), and an eccentric cam 106 (the cam mechanism of the present invention). An example) and a tension spring 107 (an example of the holding portion of the present invention).

  The input gear 101 is fixed to the rotating shaft 25C of the driven roller 25B. The input gear 101 is fixed to a front end of the rotary shaft 25C and a position deviating forward from the conveyance path of the printing paper P in the discharge path 26A. This position is a position where the printing paper P does not pass. Since the input gear 101 is fixed at the position, the input gear 101 and the printing paper P do not interfere with each other.

  The intermediate gears 102 to 104 transmit the rotational driving force from the rotary shaft 25 </ b> C to the output gear 105 via the input gear 101. The intermediate gears 102 to 104 are provided in the transmission path from the input gear 101 to the output gear 105. Specifically, the intermediate gear 102 is meshed with the input gear 101. The intermediate gear 103 is meshed with the intermediate gear 102 and the intermediate gear 104. The intermediate gear 104 is meshed with the intermediate gear 103 and the output gear 105.

  Note that the transmission ratio from the input gear 101 to the output gear 105 is determined to be a ratio at which the rotational speed of the rotary shaft 25C is reduced and transmitted to the support shaft 105A.

  The output gear 105 transmits the rotational driving force transmitted through the input gear 101 and the intermediate gears 102 to 104 to the eccentric cam 106. The output gear 105 includes a support shaft 105A that is rotatably supported by the frame of the paper discharge unit 30 or the like. When the rotational driving force is transmitted to the output gear 105, 105A rotates around the support shaft. In the present embodiment, three intermediate gears 102 to 104 are interposed between the input gear 101 and the output gear 105. Therefore, when the driven roller 25B is rotated in the rotation direction, the output gear 105 is also rotated in the rotation direction. That is, in FIG. 5, when the driven roller 25 </ b> B rotates in the counterclockwise rotation direction that is the positive rotation direction, the output gear 105 also rotates in the counterclockwise rotation direction.

  The eccentric cam 106 converts the rotational driving force of the driven roller 25 </ b> B in the positive rotation direction into a linear driving force and transmits the linear driving force to the displacement member 90. As shown in FIG. 4, the eccentric cam 106 is attached to the support shaft 105 </ b> A of the output gear 105. Specifically, the eccentric cam 106 is fixed to the support shaft 105A so that the output gear 105 and the eccentric cam 106 rotate in conjunction with each other. The degree of eccentricity of the eccentric cam 106 is determined according to the movement range of the displacement member 90. In the present embodiment, the degree of eccentricity (eccentricity) of the eccentric cam 106 is determined such that the displacement member 90 can reciprocate in the range from the first position to the second position. The eccentric cam 106 is an example of a cam mechanism that transmits a force that moves the displacement member 90, and various cams may be used instead of the eccentric cam 106 as long as the force can be transmitted. be able to.

  The tension spring 107 elastically biases the displacement member 90 from the first position to the second position. The tension spring 107 is, for example, a coil spring. As shown in FIG. 5, the left end of the tension spring 107 is connected to the lower part of the displacement member 90. The right end of the tension spring 107 is connected to a support portion 109 provided on the frame of the paper discharge portion 30. As a result, the tension spring 107 constantly biases an elastic force in a direction of pulling the displacement member 90 toward the second position. The tension spring 107 is an example of an elastic member that urges such an elastic force, and various elastic members may be used in place of the tension spring 107 as long as such an elastic force is possible. be able to.

  Hereinafter, operations of the drive transmission mechanism 100 and the displacement member 90 will be described with reference to FIGS. 5 and 6. As shown in FIG. 5A, when the driven roller 25B is rotated in the forward rotation direction (the direction indicated by the arrow Y1 in FIG. 5A), the rotational driving force is applied to the input gear 101 and the intermediate gear. 102 to 104 and the output gear 105 are transmitted to the support shaft 105A. The rotational driving force is transmitted to the eccentric cam 106 from the support shaft 105A. Thereby, the eccentric cam 106 rotates in the same rotation direction as the driven roller 25B. As the eccentric cam 106 rotates, the displacement member 90 moves in the left-right direction 8 and reciprocates between the first position and the second position. For example, the driven roller 25B is rotated when the displacement member 90 is in the second position shown in FIG. Then, the displacement member 90 starts to move from the second position toward the first position against the biasing force of the tension spring 107 by the eccentric cam 106. When the eccentric cam 106 further rotates, the projecting portion 92 projects from the wall portion 82 to the paper discharge space 21 side through the slit 85 and the opening 83 in the process in which the displacement member 90 moves to the first position (see FIG. 5 (B)). When the eccentric cam 106 further rotates, the displacement member 90 reaches the first position shown in FIG. 5C, and the protrusion amount of the protrusion 92 of the displacement member 90 is maximized.

  When the eccentric cam 106 further rotates, the displacement member 90 starts to move from the first position toward the second position by the eccentric cam 106 (see FIG. 6A). At this time, if there is no urging force of the tension spring 107, a gap is generated between the displacement member 90 and the eccentric cam 106. However, since a biasing force in the right direction is applied by the tension spring 107, the displacement member 90 moves from the first position toward the second position. When the eccentric cam 106 further rotates, the displacement member 90 returns to the second position shown in FIG. 6B, and the projecting portion 92 is disposed at a position buried inside the wall portion 82.

  In the present embodiment, the displacement member 90 continues to reciprocate between the first position and the second position rotation while the driven roller 25B continues to rotate in the normal rotation direction. On the other hand, when the rotation of the driven roller 25B is stopped, the reciprocating movement of the displacement member 90 is also stopped.

  When the rotation of the driven roller 25 </ b> B stops, the rotational driving force is not transmitted from the output gear 105 to the eccentric cam 106. In this case, since the eccentric cam 106 does not rotate, the eccentric cam 106 does not apply a force for moving the displacement member 90 to the displacement member 90.

  On the other hand, as described above, the tension spring 107 constantly urges the displacement member 90 toward the second position. This urging force is transmitted to the eccentric cam 106 via the displacement member 90 and acts in the direction in which the eccentric cam 106 is rotated. By providing the drive transmission mechanism 100 with a one-way clutch that transmits the drive force to the eccentric cam 106 only when the driven roller 25B rotates in the forward rotation direction, for example, as shown in FIG. Even if the driven roller 25 </ b> B stops in a state where the displacement member 90 is at the position to be displaced, the eccentric cam 106 rotates by receiving the biasing force of the tension spring 107 from the displacement member 90. As a result, the displacement member 90 moves in the pulling direction of the tension spring 107, moves to the second position shown in FIG. 5A, and is held at that position. Of course, without providing a one-way clutch in the drive transmission mechanism 100, a mechanism for releasing the pressure contact between the driven roller 25B and the drive roller 25A when the discharge roller pair 25 is stopped is provided, or a stop torque is used as the discharge motor. It is also possible to use a motor that does not have a motor. Also in this case, when the discharge roller pair 25 is stopped, the displacement member 90 moves in the pulling direction of the tension spring 107 and is held at the second position shown in FIG.

  As described above, the displacement member 90 is provided in the paper discharge unit 30, and the displacement member 90 reciprocates between the first position and the second position by the drive transmission mechanism 100. For this reason, as shown in FIG. 7A, even when the print paper P is discharged from the paper discharge port 37, even if the rear end of the print paper P is caught by the upper end 82A of the wall portion 82, the displacement member When the 90 moves back and forth, the protrusion 92 pushes the rear end of the printing paper P outward. Thereby, the rear end of the printing paper P is removed from the upper end 82A. Further, the protruding portion 92 is immersed in the wall portion 82 after the printing paper P is pushed out. Therefore, the rear end of the pushed printing paper P falls to the support surface 81A of the support portion 81 without being caught by the protruding portion 92 and is supported by the paper discharge tray 80. Further, even when the trailing edge of the printing paper P is caught, the catching is immediately removed, so that a stacking failure in the paper discharge tray 80 can be prevented.

  In addition, since the protruding portion 92 appears and disappears with respect to the opening 83 formed on the upper end side of the wall portion 82, the printing paper does not interfere with the plurality of printing papers P previously stacked on the paper discharge tray 80. The rear end of P can be removed.

  Further, since the rotational driving force of the driven roller 25B is transmitted to the eccentric cam 106 by the drive transmission mechanism 100 to move the displacement member 90, the displacement member 90 can be moved with a simple configuration without requiring a new drive source. Can be realized.

  In addition, since the inclined surface 92A is formed at the end of the protruding portion 92 in the protruding direction, the upper end of the inclined surface 92A can easily come into contact with the rear end of the printing paper P.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described. About the structure which is common in the above-mentioned 1st Embodiment, the description is abbreviate | omitted by attaching | subjecting the same code | symbol and showing. The same applies to the following embodiments. In the above-described first embodiment, the example in which the upper end of the slit 85 on the left side surface 30A is formed up to the bottom surface 64B of the accommodating portion 64A has been described. However, in the paper discharge unit 30 and the image forming apparatus 10, the slit 85 is As shown in FIG. 4, the shape may be a shape extending further upward beyond the bottom surface 64B. In this case, the slit 85 is formed on the left side surface 30A between the driving roller 25A and the driven roller 25B in a top view. Further, the opening 83 is formed between the driving roller 25A and the driven roller 25B in the wall portion 82 in a top view. Further, the upper end of the slit 85 reaches a position that does not exceed the nip portion between the driving roller 25A and the driven roller 25B. With respect to such a slit 85, the protruding portion 92 of the displacement member 90 protrudes upward from the upper end of the receiving portion 91, and the upper end thereof is arranged to reach the upper end of the slit 85. 8A and 8B, as the displacement member 90 reciprocates, the protrusion 92 causes the rear end of the printing paper P to be left on the inclined surface 92A. Can be pushed in the direction of pushing out. Further, since the inclined surface 92A is inclined to the upper left, the rear end of the printing paper P is pushed obliquely downward to the left. For this reason, after the catch is removed, the printing paper P easily falls to the support surface 81A of the paper discharge tray 80.

[Third Embodiment]
Hereinafter, a third embodiment of the present invention will be described. In addition to the configuration of the first embodiment described above, the paper discharge unit 30 and the image forming apparatus 10 include a one-way clutch 128 as an example of a blocking unit of the present invention, as shown in FIG. Also good. The one-way clutch 128 blocks transmission of the rotational driving force of the driven roller 25B by the drive transmission mechanism 100 when the driven roller 25B is rotated in the reverse rotation direction opposite to the normal rotation direction.

  When the one-way clutch 128 is not provided, when the driven roller 25B is rotated in the reverse rotation direction, the rotational driving force is transmitted to the eccentric cam 106 via the drive transmission mechanism 100, and the eccentric cam 106 is rotated. Let At this time, the displacement member 90 is reciprocated. However, when the driven roller 25B is rotated in the reverse rotation direction, the printing paper P is conveyed to the reverse conveyance path 39, and in this case, it is not necessary to move the displacement member 90. Therefore, in this embodiment, when the driven roller 25B is rotated in the reverse rotation direction, the one-way clutch 128 (see FIG. 9) is interposed between the driven roller 25B and the eccentric cam 106 in order to cut off the drive transmission. Reference) is provided. The one-way clutch 128 is attached to a bearing portion of the output gear 105, for example. Thereby, only the rotation of the driven roller 25 </ b> B in the positive rotation direction can be transmitted to the eccentric cam 106. That is, the eccentric cam 106 can transmit the force to the displacement member 90 and move the displacement member 90 only when the driven roller 25B rotates in the positive rotation direction. As a result, when the printing paper P is transported to the reverse transport path 39, the eccentric cam 106 and the displacement member 90 do not operate wastefully, so that wear of each member is prevented and sound generated during operation is reduced. .

[Fourth Embodiment]
The fourth embodiment of the present invention will be described below. In the first embodiment described above, the configuration in which the drive transmission mechanism 100 has a plurality of gears has been described. However, as shown in FIG. 11, the drive transmission mechanism 100 is provided with eccentric cams 106 at both ends of the rotating shaft 25C. It may be a configured. The eccentric cam 106 receives the rotational driving force of the driven roller 25B directly from the rotary shaft 25C and transmits it to the displacement member 90. In this case, the eccentric cam 106 is an example of the drive transmission mechanism of the present invention. Even with such a configuration, the displacement member 90 can be reciprocated to the first position and the second position.

  In each of the above-described embodiments, the mechanism for transmitting the rotational driving force of the driven roller 25B to the displacement member 90 has been described. However, the drive transmission mechanism 100 transmits the rotational driving force of the driving roller 25A to the displacement member 90. It may be.

  Further, the protruding end portion of the protruding portion 92 of the displacement member 90 may have an inclined surface 92A, or may have an inclined surface inclined in the opposite direction. Of course, the shape of the protruding end portion may be any shape as long as the printing paper P can be extruded.

10: image forming apparatus 14: image forming unit 25: discharge roller pair 30: paper discharge unit 37: paper discharge ports 62 to 65: conveyance guide 80: paper discharge tray 81: support unit 82: wall 90: displacement member 100: Drive transmission mechanism

Claims (10)

A discharge unit having a rotating body for discharging the sheet member to the outside from the sheet discharge port by being rotated in a predetermined positive rotation direction;
A sheet support portion for supporting the sheet member discharged from the sheet discharge port;
A wall portion extending upward from the end portion on the sheet discharge port side of the sheet support portion toward the sheet discharge port;
Provided on the inner side of the apparatus with respect to the wall portion, can protrude from the outer surface of the wall portion to the outside through an opening formed in the wall portion, and can press the rear end of the sheet member discharged from the sheet discharge port A displacement member displaceable between a first position and a second position buried inside the outer surface;
A drive transmission unit that operates in conjunction with the rotation of the rotating body in the positive rotation direction and transmits a driving force for displacing the displacement member between the first position and the second position to the displacement member; A sheet discharging apparatus comprising: The opening is formed on the upper end side of the wall portion,
The displacement member includes a receiving portion that receives the driving force transmitted by the drive transmission portion, and protrudes outward from the opening when disposed at the first position, and the opening when disposed at the second position. The sheet discharging apparatus according to claim 1, further comprising: a protruding portion that is immersed therein.   The sheet discharging apparatus according to claim 1, wherein the drive transmission unit includes a cam mechanism that transmits a rotational force of the rotating body in the positive rotation direction to the displacement member.   The drive transmission unit includes a transmission gear that transmits the driving force from a rotation shaft of the rotating body to the cam mechanism, and the cam mechanism is an eccentric cam attached to a support shaft of the transmission gear. The sheet discharging apparatus according to 3.   The sheet discharging apparatus according to claim 3, wherein the cam mechanism is an eccentric cam attached to a rotation shaft of the rotating body.   The cutoff part which interrupts | blocks transmission of the said driving force by the said drive transmission part when the said rotary body rotates in the reverse rotation direction opposite to the said normal rotation direction is provided in any one of Claim 3-5. Sheet ejector.   The sheet discharging apparatus according to claim 6, wherein the blocking unit is a one-way clutch that is provided between the rotating body and the cam mechanism and transmits only the rotation in the forward rotation direction.   The sheet discharging apparatus according to claim 1, further comprising a holding portion that holds the displacement member at the second position when the rotating body is stopped.   The sheet discharging apparatus according to claim 8, wherein the holding portion is an elastic member that elastically biases the displacement member from the first position toward the second position.   An image forming apparatus comprising the sheet discharge device according to claim 1.

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