JP5802806B2 - Recording medium discharging apparatus and image forming apparatus having the same - Google Patents

Description

  The present invention relates to a recording medium ejecting apparatus for ejecting a sheet-like recording medium and an image forming apparatus provided with the recording medium ejecting apparatus, which are mounted on an image forming apparatus such as a copying machine, a printer, and a facsimile. The present invention relates to an improvement in the loadability of a recording medium on a recording medium discharge tray to be held and the detectability of a full state of the loaded recording medium.

  In a conventional image forming apparatus, in order to ensure the stacking capacity and good stackability of discharged paper, the length and gradient of the tray surface have predetermined dimensions and predetermined in accordance with the paper size, paper discharge speed, etc. It is set to an angle. In order to prevent the stacked paper from blocking the paper discharge port, a full load detection mechanism is provided for detecting whether or not the amount of paper discharged to the paper discharge tray is a predetermined amount or more.

  By the way, the paper heated and pressed by the fixing unit of the image forming apparatus may be largely curled (rolled) depending on conditions such as the paper thickness and moisture content of the paper and the roller pressure of the pressure roller of the fixing unit. is there. When the paper is locally curled in this way, the alignment and stackability of the paper discharged onto the paper discharge tray are significantly impaired. In addition, when the trailing edge of the sheet discharged onto the sheet discharge tray is curled upward, the trailing edge of the sheet blocks the sheet discharge port before the sheet stacking amount reaches a predetermined amount.

  Therefore, as disclosed in Patent Documents 1 and 2, conventionally, a sheet pressing member is extended from the upper part of the sheet discharge port substantially vertically downward with respect to the sheet discharge direction, and the curled sheet is pressed to press the sheet. Alignment and loadability were improved. For example, Patent Document 1 has a configuration in which the left and right ends of a sheet that is particularly likely to curl are effectively pressed by setting the mounting position of Mylar, which is a pressing means, to an optimal range.

  Further, in Patent Document 2, the sheet pressing member is provided coaxially with the full load detection member, the narrow paper is pressed only by the full load detection member, and the wide paper is pressed by both the sheet press member and the full load detection member. It is configured to press with an appropriate pressing force according to the paper width.

JP 2004-123395 A JP 2005-96964 A

  However, since the pressing means (mylar) of Patent Document 1 and the sheet pressing member of Patent Document 2 are sheet-like or plate-like members for pressing the curls at both ends in the width direction of the paper, the trailing edge of the paper is When curled upward, the curled portion could not be effectively pressed.

  In view of the above problems, an object of the present invention is to provide a recording medium discharge device that can suppress both curl at both ends in the width direction of the recording medium and curl at the rear end, and an image forming apparatus including the recording medium discharge device.

  To achieve the above object, the present invention provides a discharge port for discharging a recording medium, a discharge tray on which the recording medium discharged from the discharge port is loaded, and the vicinity of the downstream side of the discharge port with respect to the recording medium discharge direction. Are supported in a swingable manner in parallel with the discharge direction, and face a side opposite to the discharge port, and protrude from the lower end of the side surface to the downstream side in the recording medium discharge direction, and the rear end of the recording medium discharged from the discharge port And a pressing member having a bottom surface that can press from above, and a corner of the corner where the side surface and the bottom surface intersect is an acute angle.

  According to the present invention, in the recording medium discharging apparatus having the above-described configuration, the corner portion is positioned upstream of the swing shaft of the pressing member in the recording medium discharging direction in a state where the pressing member is stationary due to its own weight. It is characterized by having.

  According to the present invention, in the recording medium discharging apparatus having the above-described configuration, the bottom surface portion is inclined downward toward the downstream side in the discharging direction while the pressing member is stationary due to its own weight.

  According to the present invention, in the recording medium ejecting apparatus having the above-described configuration, the pressing member is disposed so as to protrude from the surface of the corner portion, and has a driven rotating body that is rotatable in the recording medium conveyance direction. .

  According to the present invention, in the recording medium discharging apparatus having the above-described configuration, a plurality of the driven rotators are arranged at positions corresponding to dimensions in the width direction of the recording medium discharged from the discharge port.

  According to the present invention, in the recording medium ejecting apparatus having the above-described configuration, the driven rotating body is disposed over substantially the entire width direction of the pressing member.

  According to the present invention, in the recording medium discharging apparatus having the above-described configuration, the recording medium loaded on the discharge tray from a reference position closest to the discharge tray is arranged near the downstream side in the discharge direction of the pressing member. A full-load detection member that swings in the same direction as the pressing member until a detection position to be detected is provided, and the pressing member contacts the full-load detection member from the upstream side in the discharge direction, thereby causing the full-load detection member to move to the detection position. It is characterized by swinging together with the pressing member.

  Further, the present invention provides the recording medium discharge apparatus having the above-described configuration, wherein a plurality of the full load detection members are provided along the discharge port, and the pressing member is located on the outermost side among the plurality of full load detection members. It is characterized by contacting only the full load detection member.

  According to the present invention, in the recording medium discharging apparatus having the above-described configuration, the full load detection member swings around a swing shaft different from the pressing member.

  The present invention is also an image forming apparatus on which the recording medium discharging apparatus having the above-described configuration is mounted.

  According to the first configuration of the present invention, the leading end of the recording medium discharged from the discharge port hits the side surface of the pressing member and enters the discharge tray while swinging the pressing member, and the trailing end angle of the recording medium Since the portions are stacked while being pressed by the bottom surface portion of the pressing member, it is possible to effectively press the curls at both ends in the width direction and the curls at the rear end of the recording medium.

  Further, according to the second configuration of the present invention, in the recording medium ejecting apparatus according to the first configuration, the pressing member has a corner portion where the side surface portion and the bottom surface portion intersect with each other while the holding member is stationary due to its own weight. By being positioned upstream of the rocking shaft of the pressing member with respect to the discharging direction, when the curl at the rear end of the recording medium pushes up the upstream side in the discharging direction of the bottom surface, the pressing member is positioned downstream in the recording medium discharging direction. It becomes difficult to swing, and it becomes difficult to separate the bottom surface portion from the top surface of the recording medium loaded.

  Further, according to the third configuration of the present invention, in the recording medium discharging apparatus according to the second configuration, the pressing member is stationary with its bottom surface inclined downward toward the downstream side in the discharging direction by its own weight. Thus, when the curl at the rear end of the recording medium pushes up the upstream side in the ejection direction of the bottom surface portion, the pressing member becomes more difficult to swing to the downstream side in the recording medium ejection direction.

  Further, according to the fourth configuration of the present invention, in the recording medium ejecting apparatus of the second or third configuration, the driven rotating body that is rotatable in the recording medium conveyance direction is provided at the corner of the pressing member. By disposing the recording medium so as to protrude from the surface, when the recording medium once discharged during double-sided printing is drawn into the image forming apparatus, the end in the width direction of the recording medium is drawn along the corner of the pressing member. Since the driven rotator is provided in the part, the friction between the recording medium and the corner part is reduced. Accordingly, it is possible to effectively suppress the skew of the recording medium and the occurrence of a paper jam.

  According to the fifth configuration of the invention, in the recording medium discharging apparatus having the fourth configuration, a plurality of driven rotating bodies are arranged at positions corresponding to the widthwise dimension of the recording medium discharged from the discharge port. Thus, the friction between the recording medium discharged from the recording medium discharging apparatus and the corners of the pressing member can be effectively reduced.

  Further, according to the sixth configuration of the present invention, in the recording medium ejecting apparatus of the fourth configuration, the driven rotating body is arranged over substantially the entire width direction of the pressing member, thereby removing the recording medium ejecting device. The friction with the corners of the pressing member can be effectively reduced regardless of the width-direction dimension of the discharged recording medium. In addition, the pressing member can be used also among a plurality of types of recording medium ejecting apparatuses having different widthwise dimensions of the recording medium to be used.

  According to the seventh configuration of the present invention, in the recording medium discharging apparatus having any one of the first to sixth configurations, the full load detection member that swings in the same direction as the press member is provided, and the press member is fully loaded. By contacting the detection member from the upstream side in the discharge direction and swinging the full-load detection member together with the pressing member, the load detection by the full-load detection member can be detected even when the pressing member is rotated downstream in the recording medium discharge direction. Therefore, it is possible to notify the user that the discharge port may be blocked by the curl at the rear end of the recording medium.

  According to the eighth configuration of the invention, in the recording medium discharging apparatus according to the seventh configuration, the pressing member is a full load located on the outermost side among a plurality of full load detection members provided along the discharge port. By contacting only the detection member, the curl at the rear end of the recording medium is small, and when a medium or small size recording medium that does not need to be pressed by the pressing member is loaded, only the full detection member is rotated to load the full load. The state can be detected with high accuracy.

  Further, according to the ninth configuration of the present invention, in the recording medium ejecting apparatus of the seventh or eighth configuration, the full load detection member swings around a swing shaft different from the press member, There is no possibility that the member rotates with the full load detection member. Therefore, when a medium-sized or small-sized recording medium that does not contact the pressing member is stacked, the full-load detecting member is not subjected to the rocking load of the pressing member, and even a small-sized recording medium that is relatively weak is discharged. It can be smoothly loaded on the tray. Further, it is possible to detect the full state of the recording medium with high accuracy.

  Further, according to the tenth configuration of the present invention, by mounting the recording medium ejecting apparatus having any one of the first to ninth configurations, curling at both ends in the width direction and the rear end of the recording medium is effective. The image forming apparatus can suppress the occurrence of recording medium stacking failure and ejection failure.

Front sectional view showing the internal configuration of the image forming apparatus 100 on which the paper discharge device 80 of the present invention is mounted. The partial perspective view of the paper discharge apparatus 80 which concerns on 1st Embodiment of this invention. Enlarged view of the vicinity of the sheet pressing member 61 in the sheet discharge device 80 of the first embodiment. An external perspective view of an example of a sheet pressing member 61 used in the sheet discharge device 80 of the first embodiment as viewed from the front side. External perspective view of the paper pressing member 61 used in the paper discharge device 80 of the first embodiment as seen from the back side. Side surface sectional view of the paper discharge device 80 according to the first embodiment showing a state in which large-size paper is stacked on the paper discharge tray 60. The partial perspective view of the paper discharge apparatus 80 of 1st Embodiment which shows the state in which the load amount of the large sized paper on the paper discharge tray 60 increased. 7 is an enlarged view around the sheet pressing member 61 in FIG. The side view which shows the other structural example of the paper pressing member 61 used for the paper discharge apparatus 80 of 1st Embodiment. The partial perspective view which shows a mode that the paper P is switched back by the paper discharge apparatus 80 of 1st Embodiment. Side surface sectional drawing which shows a mode that the paper P is switched back by the paper discharge apparatus 80 of 1st Embodiment. Enlarged view of the vicinity of the sheet pressing member 61 in the sheet discharge apparatus 80 according to the second embodiment of the present invention. External perspective view of the paper pressing member 61 used in the paper discharge device 80 of the second embodiment as seen from the front side. External perspective view of the paper pressing member 61 used in the paper discharge device 80 of the second embodiment as seen from the back side. Side surface sectional drawing which shows a mode that the paper P is switched back by the paper discharge apparatus 80 of 2nd Embodiment. A rear view showing another configuration example of the sheet pressing member 61 used in the sheet discharge device 80 of the second embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a front sectional view showing an internal configuration of an image forming apparatus equipped with a paper discharge device of the present invention. The image forming apparatus 100 of the present invention is a so-called in-cylinder discharge type digital copying machine, and mainly includes an apparatus main body 20 and an image reading unit 21 disposed on the apparatus main body 20. The image reading unit 21 is provided with various mechanisms, which will be described later, for reading an image of a document as an electrical signal. On the other hand, the apparatus body 20 transfers an image to a sheet based on the read electrical signal of the document image. Various mechanisms to be described later are provided.

  In FIG. 1, the apparatus main body 20 is composed of a lower housing 20a and a connecting housing 20b that is positioned along the left side and is connected to the image reading unit 21, and the lower housing 20a has a paper supply. A paper part, an image forming part for forming a toner image on the paper, a fixing part for fixing the toner image on the paper, and the like are provided. On the other hand, the fixed paper is conveyed to the connection housing 20b. A paper discharge device for discharging is provided.

  An in-cylinder discharge space 22 is formed on the right side of the connecting housing 20b immediately below the image reading unit 21 and is open to the right side and the front. A paper discharge tray 60 is provided for receiving and stacking paper discharged in the horizontal direction from the right side surface of the connecting housing 20b. A paper discharge port 53 is provided on the side surface of the connecting housing 20 b so as to communicate with the in-body discharge space 22, and discharges the paper onto the paper discharge tray 60. A leading end regulating member 38 is provided at the downstream end of the paper discharge tray 60 in the discharge direction so that the discharged paper does not slide off the tray surface.

  On the upper surface of the image reading unit 21, a document placing table 25 made of a transparent glass plate and an operation panel 26 exposed on the front side are disposed. Further, above the image reading unit 21, a document press 28 equipped with a document transport device 27 for transporting a document to the image reading position of the document placing table can be opened and closed by a hinge part on the back of the image reading unit 21. It is supported.

  Next, the configuration of the document conveying device 27 will be described. In the document cover 30, document conveyance means including a pickup roller 32, a conveyance roller pair 33, a registration roller pair 34, and a discharge roller pair 35 is provided in order from the upstream side along the document conveyance path d. Among these, the conveyance roller pair 33 includes a driving roller 33a and a separation roller 33b. The separation roller 33b has a built-in torque limiter, and the driving roller 33a and the driven rotation are performed only when the rotational load exceeds a predetermined torque. It is supposed to be.

  Between the registration roller pair 34 and the discharge roller pair 35, a white reference plate 36 for shading correction, which is exposed to face the image reading position R on the document placing table 25, and a white reference plate 36 behind the white reference plate 36 A document pressing portion 36a for pressing the reference plate 36 toward the image reading position R is provided. The document conveyance path d is curved in a U shape so as to be reversed between the conveyance roller pair 33 and the image reading position R.

  A plurality of sensors for detecting the presence or absence of a document are provided at appropriate positions on the document transport path d. For example, a document detection sensor S1 is provided at the center of the document feed tray 29, a paper feed sensor S2 is provided downstream of the transport roller pair 33, and a discharge sensor S3 is provided downstream of the discharge roller pair 35. ing.

  The image reading unit 21 has a sheet-through method in which a document is automatically conveyed and read by a document conveying device 27 with the document retainer 28 closed, and the document retainer 28 is opened and closed each time a document is read. Two types of reading methods are possible: a document fixing method that replaces one by one. In the former sheet-through method, a document reading operation is performed while the optical system provided in the image reading unit 21 is held at a predetermined position without scanning and moving. On the other hand, in the latter document fixing method, A reading operation is performed while the optical system scans and moves.

  Next, the document conveying operation by the sheet-through type document conveying unit 27 will be described with reference to FIG. In the sheet-through type document conveying operation, first, a plurality of documents set with the image surface facing upward on the document feeding tray 29 are set by a set document pressing member 37 biased upward by a spring member 37a. Is pressed against the pickup roller 32 by the pressure of Here, when the copy start button on the operation panel 26 is turned on, the pickup roller 32 and the transport roller pair 33 are rotationally driven by primary paper feed driving means (not shown).

  The document set on the document feed tray 29 is normally fed by the pickup roller 32 to a plurality of transport rollers 33 at the upper stage. The plurality of originals sent to the conveyance roller pair 33 are separated by the separation roller 33 b and only the uppermost one is separated and conveyed toward the registration roller pair 34. At that time, after the document is conveyed by a predetermined distance after the leading edge of the document is detected by the sheet feeding sensor S2, the driving roller 33a and the pickup roller of the conveyance roller pair 33 are stopped by the operation of the primary sheet feeding driving unit being stopped. The rotational drive of 32 is stopped and the primary paper feeding is completed. The document that has been primarily fed is stopped with its leading end pressed against the nip portion of the registration roller pair 34 and with its leading end being bent.

  Secondary feeding is started after a lapse of a predetermined time from completion of primary feeding. That is, the registration roller pair 34 is rotationally driven by the operation of the secondary paper feed driving means (not shown). The document is conveyed by the registration roller pair 34 toward the discharge roller pair 35 through the image reading position R, and finally discharged onto the document discharge tray 31 by the discharge roller pair 35. At this time, the completion of image reading of one original is detected by detecting passage of the rear end of the original by the discharge sensor S3.

  Here, the discharge sensor S3 has a counting function that counts the number of documents every time the document feed and conveyance is completed. If the document detection sensor S1 detects a subsequent document, the second and subsequent document conveyance is performed. Will continue as above. When the document passes through the image reading position R, the document is conveyed while being lightly pressed toward the document placing table 25 by the white reference plate 36 and the document pressing portion 36a, and the image of the document is read through the image reading position R. It is supposed to be.

  Next, the configuration in the image reading unit 21 will be described below with reference to FIG. In the image reading unit 21, a lamp 1 that is a light source that irradiates light toward the image surface of the document, a reflector 2 that efficiently applies light from the lamp 1 to the image surface of the document, and document reflection A first mirror 3 that receives and reflects light directly, a second mirror 4 that receives and reflects light reflected from the first mirror 3, and a third mirror that receives and reflects light reflected from the second mirror 4. A mirror 5, and a lens barrel 6 that holds a lens group (not shown) that introduces and collects reflected light from the third mirror 5, and is condensed by the lens group of the lens barrel 6. A photoelectric conversion module (for example, a line type CCD) 7 that receives reflected light from the original and converts it into an electrical signal is disposed on the base plate 10. The optical path of the original reflected light is indicated by a one-dot chain line.

  Here, the lamp 1, the reflector 2 and the first mirror 3 are integrally fixed on the first carriage 8, and the second mirror 4 and the third mirror 5 are integrally fixed on the second carriage 9. The first carriage 8 and the second carriage 9 are independent of each other, but can reciprocate in cooperation. That is, when the document image reading operation is performed by the sheet through method, the first carriage 8 is moved and held immediately below the image reading position R, and the second carriage 9 is held at a predetermined position. On the other hand, in the original fixing method, the first carriage 8 and the second carriage 9 reciprocate (scan) while maintaining the optical path length of the original reflected light constant.

  Under such a configuration, the document reflected light irradiated from the lamp 1 and reflected by the image surface of the document is reflected by the first mirror 3 to the third mirror 5 and introduced into the lens group in the lens barrel 6. The light is condensed by the lens group and imaged on the photoelectric conversion element of the photoelectric conversion module 7. The photoelectric conversion module 7 performs photoelectric conversion processing, and the document image is read as an electric signal.

  Next, the configuration of various mechanisms provided in the apparatus main body 20 for transferring the image to the sheet based on the electric signal of the read document image will be described below with reference to FIG. First, the sheet feeding unit will be described. Under the lower housing 20a, various sizes of sheets (paper, OHP sheets, etc.) are stored, and a paper feed cassette 40 that can be taken in and out from the front is disposed. The size paper P is fed out one by one by the feeding roller 40a. The left side surface of the lower portion of the lower housing 20a is provided with an openable / closable manual feed tray 41 that can be pulled down as necessary. The small-size paper P ′ set in the manual feed tray 41 is fed out. It is sent out one by one by the roller 41a.

  Next, an image forming unit for forming a toner image on a sheet and a fixing unit for fixing the toner image on the sheet will be described. Above the paper feed cassette 40 in the lower housing 20a, a photosensitive drum 42 constituting a main image forming unit, and a charging device 43, a laser exposure unit 44, a developing device 45, around the photosensitive drum 42, A transfer roller 46 and a cleaning device 47 are provided. Further, a fixing device (fixing unit) 48 is disposed above the transfer roller 46 in the lower housing 20a and directly below the connecting housing 20b.

  The photosensitive drum 42 is made of, for example, positively charged amorphous silicon, and rotates clockwise in FIG. 1 at a predetermined peripheral speed when driven. The surface of the photosensitive drum 42 is uniformly charged by corona discharge generated from the charging device 43 to which a high voltage is applied, and then the laser exposure unit 44 based on the electrical signal of the original image from the photoelectric conversion module 7 described above. The electrostatic latent image composed of a predetermined light potential and dark potential portion is formed by the irradiation of the light beam from.

  Further, the electrostatic latent image rotates to the developing position by the rotation of the photosensitive drum 42. The developing roller 45a, which is a component of the developing device 45, is made of stainless steel and has a fixed magnet inside. The developing roller 45a is rotatably supported with a predetermined gap from the photosensitive drum 42, and in the same direction as the photosensitive drum 42 when driven. At a predetermined peripheral speed. The developing device 45 is filled with, for example, a positively charged magnetic toner having a volume average particle diameter of 9 μm (median diameter measured by a Coulter counter), and a toner thin film is formed on the surface of the developing roller 45a by a magnetic blade (not shown). A layer is formed. A predetermined developing bias voltage is applied to the developing roller 45a. The toner that has reached the developing region flies from the surface of the developing roller 45a by the developing bias voltage, and is attracted to the electrostatic latent image on the surface of the photosensitive drum 42, whereby a toner image is formed (developed).

  Here, on the paper P (or P ′) that is fed out from the paper feed cassette 40 (or the manual feed tray 41) one by one and reaches the paper feed registration roller pair 49, the toner image on the photosensitive drum 42 is transferred to the transfer roller. In synchronism with approaching 46, the sheet is fed upward while the conveyance timing is adjusted by the pair of paper feeding registration rollers 49, and conveyed between the photosensitive drum 42 and the transfer roller 46 through the conveyance path T <b> 1. . Then, most of the toner in the toner image is transferred onto the paper P when the leading edge of the paper P and the leading edge of the toner image pass through the transfer roller 46.

  The toner remaining on the surface of the photosensitive drum 42 without being transferred onto the paper P is removed from the photosensitive drum 42 by the cleaning device 47. On the other hand, the paper P on which the toner image is transferred is sent to the fixing device 48. The fixing device 48 includes a fixing roller pair including a heat roller 48a and a pressure roller 48b. The toner image on the paper P passing through the nip portion of the fixing roller pair is heated and pressed to fix the toner image. As a result, a fixed transfer image is formed on the paper P.

  The sheet P that has passed through the fixing device 48 is conveyed into the connecting housing 20b along the vertical conveyance path T2 that is directed vertically upward. In this connection housing 20b, a transport roller pair 50 connected to the vertical transport path T2 and a discharge roller pair 51 for discharging the paper P to the paper discharge tray 60 are disposed. The paper P sent out from the transport roller pair 50 reaches the discharge roller pair 51 through the transport path T3 and is discharged from the discharge roller pair 51 to the paper discharge tray 60 through the paper discharge port 53.

  On the other hand, in the case of double-sided printing in which images are formed on both sides of the paper P, the paper P that has passed through the fixing device 48 is once transported in the direction of the discharge roller pair 51, and a part of the paper P is discharged from the paper discharge port 53 to the paper discharge tray. 60 is drawn out. Then, after the rear end of the paper P passes through the branching portion 54, the discharge roller pair 51 is rotated in the reverse direction and the transport direction of the branching portion 54 is switched, so that the paper P is distributed to the reverse transport path T4 (switch) Back), the sheet is re-conveyed to the sheet-feeding resist roller pair 49 with the image surface reversed. Then, the next image formed on the photoconductive drum 42 is transferred to the surface of the paper P where the image is not formed by the transfer roller 46 and conveyed to the fixing device 48 to fix the toner image, and then the discharge roller. The paper is discharged from the pair 51 to the paper discharge tray 60 through the paper discharge port 53.

  2 is a partial perspective view of the paper discharge device 80 according to the first embodiment of the present invention as seen from the back side of FIG. 1, and FIG. 3 is an enlarged view of the vicinity of the paper pressing member 61 in FIG. 2 shows the vicinity of the left end portion of the paper discharge port 53, and FIGS. 2 and 3 show a state in which the image reading unit 21 is removed for convenience of explanation. The sheet discharge device 80 includes at least a sheet discharge port 53, a sheet discharge tray 60, and a sheet pressing member 61.

  In the vicinity of the downstream side of the paper discharge port 53 with respect to the paper discharge direction (the direction of arrow A in FIG. 2), a paper pressing member 61 that presses the rear end of the paper discharged from the paper discharge port 53 is provided. The sheet pressing member 61 is supported at both left and right ends of the sheet discharge port 53 so as to be swingable in the sheet discharge direction with the first swing shaft 63 (see FIG. 6) as a support shaft. Further, the sheet pressing member 61 is disposed so as to overlap with a full load detection member 70a (described later) when viewed from the sheet discharge direction.

  4 and 5 are external perspective views of the paper pressing member 61 used in the paper discharge device 80 of the first embodiment when viewed from the front side and the back side. The sheet pressing member 61 is a member integrally formed of a synthetic resin, and includes a side surface portion 61a that faces the paper discharge port 53 (see FIG. 2), and a bottom surface portion 61b that protrudes downstream from the lower end of the side surface portion 61a in the sheet discharge direction. A bearing portion 61c is formed at the upper end of the side surface portion 61a so as to be slidably fitted to the first oscillating shaft 63.

  In addition, a column portion 61d is formed so as to connect the centers of the side surface portion 61a and the bottom surface portion 61b. The column portion 61d is hollow and opens on the side surface portion 61a side. Splash-shaped irregularities 61e are formed on the end portion of the column portion 61d on the downstream side in the paper discharge direction. The column 61d serves to increase the rigidity of the paper pressing member 61 and to bias the center of gravity of the paper pressing member 61 toward the downstream side in the paper discharge direction. Further, a corner portion 62 is formed at a portion where the side surface portion 61a and the bottom surface portion 61b intersect.

  Since the sheet pressing member 61 is disposed at both ends of the sheet discharge port 53, the small-sized sheet is discharged onto the sheet discharge tray 60 without contacting the sheet pressing member 61. However, since the small-size paper is unlikely to curl at both ends and the rear end in the width direction, there is a possibility that the paper is stably stacked on the paper discharge tray 60 without the paper pressing member 61 and the paper discharge port 53 may be blocked. There is no problem because there is no.

  2 and 3, in the immediate vicinity of the downstream side of the sheet pressing member 61, a plurality of (here, 3) rocks in parallel with the sheet discharge direction according to the amount of sheets stacked on the sheet discharge tray 60. Book) full load detection members 70a, 70b, and 70c. The full load detection members 70a to 70c are fixed to a second swing shaft 71 that is swingably supported by the connecting housing 20b. Of the three full load detection members 70a to 70c, the full load detection member 70a located on the outermost side in the paper width direction is a large size (for example, A3 size) paper, and the central full load detection member 70b is a medium size (for example, A4 size). The full-sheet detecting member 70c located on the innermost side is disposed at a position where it can contact a small-size (for example, B5 size) paper.

  A light shielding plate 67 for switching the upper surface detection sensor 65 between ON and OFF is fixed to one end of the second swing shaft 71. The light shielding plate 67 reciprocates from the lowest position to the highest position of the guide groove 69 along the guide groove 69 formed on the inner wall surface of the connection housing 20b according to the swing of the full load detection members 70a to 70c.

  The upper surface detection sensor 65 is a PI (photo interrupter) sensor in which a detection unit including a light emitting unit and a light receiving unit is provided on the opposing inner surfaces of a U-shape in plan view. When the light shielding plate 67 moves to the uppermost part of the guide groove 69 and blocks the optical path of the detection unit, the light reception signal level of the detection unit is switched from HIGH to LOW, and the upper surface of the paper stacked on the paper discharge tray 60 The position, that is, the sheet stacking amount can be detected. When it is detected that the sheets on the sheet discharge tray 60 are full, for example, a message is displayed on the liquid crystal display unit of the operation panel 26 (see FIG. 1) to notify the user.

  Next, a paper discharge operation in the paper discharge device of the present embodiment will be described. 2 and 3 show a state before discharging the paper (default state). Since the center of gravity of the paper pressing member 61 is biased to the downstream side in the paper discharging direction, the bottom surface portion 61b remains stationary due to its own weight. Is inclined downward toward the downstream side in the paper discharge direction. Further, the full load detection members 70 a to 70 c are also disposed at a position (reference position) that is closest to the sheet discharge tray 60 by its own weight, and the light shielding plate 67 is positioned at the lowest position of the guide groove 69.

  FIG. 6 is a side cross-sectional view showing a state in which a large size paper is stacked on the paper discharge tray 60 in the paper discharge device 80 of the present embodiment. The leading end of a large size (for example, A3 size) paper P discharged from the discharge roller pair 51 through the paper discharge port 53 hits the side surface portion 61a of the paper pressing member 61, and the paper pressing member 61 is downstream in the paper discharging direction. Are sequentially stacked on the paper discharge tray 60 along the bottom surface portion 61b inclined downward toward the downstream side in the paper discharge direction.

  Since the rear end of the paper P is stacked in a state of being submerged below the bottom surface portion 61b of the paper pressing member 61, the rear end of the paper P discharged from the paper discharge port 53 is pressed from above by the bottom surface portion 61b. Here, as shown in FIGS. 4 and 5, the bottom surface portion 61 b of the sheet pressing member 61 has a rectangular shape that extends in the sheet discharge direction and the sheet width direction, and therefore presses the curls at both ends in the width direction of the sheet P. At the same time, the curl at the rear end of the paper P can also be pressed.

  When the sheet pressing member 61 is stationary due to its own weight, the bottom surface portion 61b is inclined downward toward the downstream side in the sheet discharge direction, and the corner portion 62 (FIG. 4) intersects the side surface portion 61a and the bottom surface portion 61b. 5) is located upstream of the first swing shaft 63 with respect to the paper discharge direction. Therefore, when the upstream side in the discharge direction of the bottom surface portion 61b is pushed up by the curl of the rear end of the paper P, a force acts to swing the paper pressing member 61 to the upstream side in the discharge direction. Accordingly, the sheet pressing member 61 does not swing to the downstream side in the sheet discharge direction, and is difficult to be separated from the upper surface of the sheet P on which the bottom surface portion 61b is stacked.

  When the loading amount of the paper P on the paper discharge tray 60 increases, the paper pressing member 61 is pushed by the upper surface of the paper P and gradually rotates downstream in the paper discharging direction. Move downstream in the paper discharge direction. For this reason, the trailing edge of the paper P cannot be sufficiently pressed. In particular, when the curling of the trailing edge of the paper P is large, the paper discharge port 53 is blocked before the paper P on the paper discharge tray 60 becomes full. There is a fear.

  7 shows the periphery of the left end portion of the paper discharge port 53 when the large-size paper stacking amount on the paper discharge tray 60 increases from the back side of FIG. FIG. 8 is a partial perspective view, and FIG. 8 is an enlarged view of the vicinity of the sheet pressing member 61 in FIG. For convenience of explanation, the description of paper is omitted in FIGS. 7 and 8. In the present embodiment, as described above, the sheet pressing member 61 is disposed so as to overlap the full load detection member 70a when viewed from the sheet discharge direction, and therefore the swinging trajectory of the sheet pressing member 61 and the full load detection member 70a also overlap. doing.

  With this configuration, the paper pressing member 61 pressed by the discharged paper contacts the full load detection member 70 a from the upstream side in the paper discharge direction, and the full load detection member 70 a swings upward together with the paper press member 61. As the full load detection member 70 a swings, the second swing shaft 71 also rotates, and the light shielding plate 67 moves upward along the guide groove 69. When the full load detection member 70a swings to a predetermined position (detection position), the light shielding plate 67 reaches the uppermost position of the guide groove 69 that shields the detection portion of the upper surface detection sensor 65, and the paper discharge tray 60 is fully loaded. And a warning message is displayed on the operation panel 26.

  Therefore, even if the upper surface of the paper P stacked on the paper discharge tray 60 does not directly contact the full load detection member 70a, the paper pressing member 61 that contacts the upper surface of the paper P rotates downstream in the paper discharge direction. Since the full load detection member 70a is pushed upward and the load amount can be detected by the full load detection member 70a and the upper surface detection sensor 65, the rear end of the paper P before the paper P on the paper discharge tray 60 becomes full. It is possible to notify the user in advance that the paper discharge port 53 may be blocked by the curl.

  Further, the sheet pressing member 61 is disposed so as to contact only the full load detection member 70a located on the outermost side in the paper width direction, and does not contact the full load detection members 70b and 70c. For this reason, when medium-sized or small-sized sheets are stacked on the sheet discharge tray 60, the full load detection member 70b or 70c is rotated to move the light shielding plate 67 from the reference position to the detection position. Detected.

  Here, since the full load detection members 70a to 70c swing around the second swing shaft 71 different from the first swing shaft 63 of the paper press member 61, the paper press member 61 together with the full load detection members 70b and 70c. There is no risk of going around. Therefore, when ejecting a small-size paper that is weaker than a large-size paper, the paper pressing member 61 is not subjected to a rocking load, and can be smoothly stacked on the paper discharge tray 60. Further, it is possible to detect the full state of the paper with high accuracy.

  In the default state shown in FIGS. 2 and 3, the sheet pressing member 61 may be in contact with the full load detection member 70a, or may be disposed at a predetermined interval from the full load detection member 70a. When there is a gap between the sheet pressing member 61 and the full load detection member 70a, the full load detection member 70a contacts the full load detection member 70a when the sheet pressing member 61 swings by a predetermined angle. And swings upward.

  As described above, the paper discharge device 80 according to the first embodiment of the present invention can accurately detect the full state of the paper discharge tray 60 regardless of the size of the discharged paper, and can further detect both ends of the paper in the width direction. In the case of discharging a large-sized sheet that easily curls at the rear end, the user can detect a full state before the curl at the rear end blocks the paper discharge port 53 and notify the user.

  The sheet pressing member 61 is not limited to the shape shown in FIGS. 4 and 5, and the side surface portion 61 a faces the leading edge of the paper discharged from the paper discharge port 53, and the downstream side in the paper discharge direction from the lower end of the side surface portion 61 a. If it is the structure which has the bottom face part 61b which protrudes in FIG. 9, the sheet | seat pressing member 61 of L shape seen from the side as shown in FIG. 9 can also be used.

  By the way, in the paper discharge device 80 of the first embodiment described above, in order to perform double-sided printing, the paper P once discharged from the paper discharge port 53 is switched back by the reverse rotation of the discharge roller pair 51 and the reverse conveying path T4. When sorting (see FIG. 1), as shown in FIG. 10, the sheet pressing member 61 is moved in the arrow C direction by friction between the upper surface and the bottom surface portion 61b of the sheet P drawn in the direction of the sheet discharge port 53 (arrow B direction). To the default state (see FIGS. 2 and 3).

  As a result, as shown in FIG. 11, the end in the width direction of the paper P is greatly bent between the upstream end (corner portion 62) of the paper pressing member 61 in the discharge direction and the nip portion of the discharge roller pair 51. A strong twist occurs in P. Due to the twisting of the paper P, the conveyance load at the end in the width direction of the paper P is rapidly increased, and the skew of the paper P is generated. The skew of the paper P causes a paper jam (jam) in the reverse conveyance path T4. The above-mentioned problem is particularly noticeable when the paper P is transported with only the edge in the width direction of the paper P contacting the paper pressing member 61 and the stiffness is weak.

  FIG. 12 is a side cross-sectional view of the vicinity of the sheet pressing member 61 of the sheet discharge apparatus 80 according to the second embodiment of the present invention. FIGS. 13 and 14 are sheets used in the sheet discharge apparatus 80 of the second embodiment. It is the external appearance perspective view which looked at the pressing member 61 from the front side and the back side. In the sheet pressing member 61 used in the present embodiment, a roller 73 is rotatably attached to a corner portion 62 where the side surface portion 61a and the bottom surface portion 61b intersect. The configuration of the other part of the sheet pressing member 61 and the configuration of the other part of the sheet discharge device 80 including the full load detection members 70a to 70c are the same as those in the first embodiment.

  FIG. 15 is a side cross-sectional view illustrating a state in which the paper P is drawn using the paper discharge device 80 of the second embodiment. As shown in FIG. 15, the end in the width direction of the paper P is drawn into the image forming apparatus 100 while contacting the corner 62 of the paper pressing member 61. Here, since the corners 62 are provided with the rollers 73, the friction between the paper P and the corners 62 is reduced.

  Therefore, the phenomenon that the sheet pressing member 61 is pulled to the default state due to friction with the sheet P can be suppressed, and the upstream end portion (corner portion 62) of the sheet pressing member 61 in the discharge direction and the nip portion of the discharge roller pair 51. No twisting occurs at the end in the width direction of the paper P. As a result, there is no increase in the conveyance load at the end in the width direction of the paper P, and therefore it is effective to generate skew (skew) when the paper P is switched back and paper jam (jam) in the reverse conveyance path T4. Can be suppressed.

  In the paper discharge device 80 of the present embodiment, the roller 73 is provided at the substantially central portion of the corner portion 62 in the width direction. However, as shown in FIG. An elongated cylindrical roller 73 may be provided. By doing so, the paper P1 having a paper width (for example, A3 size) substantially equal to the paper discharge port 53, the paper P2 having a paper width (for example, B4 size) slightly smaller than the width of the paper discharge port 53, or an intermediate size thereof. The friction between the plurality of sizes of paper and the corner 62 of the paper pressing member 61 can be effectively reduced regardless of the paper width. Further, the sheet pressing member 61 can also be used with the sheet discharge device 80 having a different sheet width.

  In addition, when the size of the paper P discharged from the paper discharge device 80 is determined, the roller 73 may be provided at a position corresponding to the paper width to be used. For example, when discharging A3 size paper P1 and B4 size paper P2, as shown in FIG. 16 (b), the paper P1 and P2 can be contacted at two corners 62 of the paper pressing member 61. A roller 73 may be provided.

  In addition, this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the meaning of this invention. For example, in each of the above-described embodiments, the paper discharge device used in the in-cylinder discharge type image forming apparatus has been described. The present invention can also be applied to a paper discharge device that is transported to the original reading unit by the apparatus and used to discharge the original after the original image has been read.

  INDUSTRIAL APPLICABILITY The present invention can be used in a recording medium discharge device that discharges a sheet-like recording medium onto a discharge tray, and is supported so as to be swingable in parallel with the discharge direction in the vicinity of the discharge port downstream in the discharge direction. A side part facing the front end of the discharged recording medium, a bottom part protruding from the lower end of the side part to the downstream side in the recording medium discharge direction and capable of pressing the rear end of the recording medium discharged from the discharge port from above, A holding member having

  Accordingly, it is possible to provide a recording medium discharge device that can effectively suppress the occurrence of curling at both ends in the width direction of the recording medium and curling at the rear end with a simple configuration.

DESCRIPTION OF SYMBOLS 20 Apparatus main body 20a Lower housing 20b Connection housing 21 Image reading part 22 In-cylinder discharge space 53 Paper discharge port 60 Paper discharge tray 61 Paper pressing member 61a Side face part 61b Bottom face part 61c Bearing part 61d Strut part 61e Concavity and convexity part 62 Corner part 63 First swing shaft 65 Upper surface detection sensor 67 Light shielding plate 69 Guide groove 70a to 70c Full load detection member 71 Second swing shaft 73 Roller (driven rotor)
80 Paper discharge device 100 Image forming device P Paper (recording medium)

Claims (7)

A discharge port for discharging the recording medium;
A discharge tray on which the recording medium discharged from the discharge port is loaded;
A side portion that is swingably supported in parallel with the discharge direction in the vicinity of the downstream side of the discharge port with respect to the recording medium discharge direction, and that is downstream of the lower end of the side portion with respect to the recording medium discharge direction. A pressing member having a bottom surface portion that protrudes from above and can press the rear end of the recording medium discharged from the discharge port from above,
With
The pressing member, Ri angle acute der the corner between the side surface portion and the bottom portion intersect, while still under its own weight, the swing axis of the pressing member and the corner portion with respect to the recording medium discharge direction recording medium discharge device that is located upstream of the. 2. The recording medium discharging apparatus according to claim 1, wherein the pressing member is stationary by its own weight, and the bottom surface portion is inclined downward toward the downstream side in the discharging direction . The recording medium discharging apparatus according to claim 1 , wherein the pressing member includes a driven rotating body that is disposed so as to protrude from a surface of the corner portion and is rotatable in a recording medium conveyance direction. . The same direction as the pressing member from the reference position closest to the discharge tray to the detection position for detecting the full load of the recording media stacked on the discharge tray is arranged in the vicinity of the downstream side of the pressing member in the discharging direction. includes a full load detecting member swings, the pressing member according to claim 1, wherein the swinging together with the pressing member of the full load detection member by abutting the discharge direction upstream side relative to the full load detecting member to the recording medium discharge apparatus according to claim 3. The full load detection member is provided in a plurality along the discharge port, and the pressing member contacts only the full load detection member located on the outermost side among the multiple full load detection members. recording medium discharge apparatus according to 4. 6. The recording medium ejecting apparatus according to claim 4 , wherein the full load detecting member swings about a swing shaft different from that of the pressing member . An image forming apparatus on which the recording medium discharging apparatus according to claim 1 is mounted .

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