Sheet discharger, and image forming apparatus

Abstract

To prevent a posture of a sheet discharged to a discharge tray from being disturbed during sheet-discharging in comparison to a case of not providing a plurality of exhaust passages inclined so as to extend toward both ends outer sides in a width direction crossing a discharge direction toward a lower side of a wall face, that are formed on the wall face of the discharge tray.SOLUTION: There are provided a discharge tray for storing a discharged sheet by abutting an end of an upstream side along a discharge direction of the sheet against a wall face; and a plurality of exhaust passages inclined so as to extend toward both ends outer sides along a width direction crossing the discharge direction of the sheet toward a lower side of the wall face, that are formed on the wall face of the discharge tray.SELECTED DRAWING: Figure 5

Description

[Technical field]

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

[0002] Conventionally, techniques relating to sheet discharging devices have already been proposed, for example, as disclosed in Patent Documents 1 to 4.

[0003] Patent document 1 is configured to include an ejection member that ejects paper, a paper stacking section on which the paper ejected by the ejection member is stacked, a trailing end regulating member that regulates the trailing end position of the paper loaded on the paper stacking section, and an exhaust means that exhausts air from a corner facing the reference surface of the trailing end regulating member and the paper stacking surface of the paper stacking section.

[0004] Patent document 2 has a discharge wall portion in which a discharge outlet is formed, discharge rollers for discharging incoming sheets from the discharge outlet, a sheet stacking portion for stacking the sheets that are discharged from the discharge outlet and fall, a suction portion that opens between the discharge outlet and the sheet stacking portion in the discharge wall portion and sucks in air below the sheets discharged from the discharge outlet, and a control portion for controlling the suction operation by the suction portion, and the control portion is configured to control the suction portion so that the suction portion starts its suction operation when the rear end of the sheet discharged from the discharge outlet leaves the discharge outlet and stops the suction operation when a predetermined time has elapsed.

[0005] Patent document 3 discloses a paper output tray having a tray attached to the side of the image forming apparatus body somewhat separated below the paper output means so as to receive and store image-formed paper discharged from the paper output means provided in the image forming apparatus body, and side walls provided along the entire length on both sides of the tray between the top of the tray and a position somewhat above the paper output means, in which the side walls on both sides of the paper output tray are configured to have sawtooth-like irregularities extending vertically and with a greater horizontal width of the slope on the upstream side in the paper output direction than on the downstream side, and air holes are provided in the wall surface along approximately the entire height.

[0006] Patent document 4 describes a full detection member that can move according to the stacking height on an output tray onto which paper is transported and stacked in order to detect the stacking height of paper. The full detection member has a contact surface portion that comes into contact with the leading edge of the transported paper, and a detection portion that is located downstream of the contact surface portion in the transport direction and can come into contact with the top layer of paper stacked on the output tray, and the contact surface portion has a hole formed therein that has an inclined edge that is inclined with respect to the transport direction of the paper. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2009-078873 A [Patent Document 2] JP 2015-212194 A [Patent Document 3] Patent No. 2896245 [Patent Document 4] JP 2020-142915 A Summary of the Invention [Problem to be solved by the invention]

[0008] The object of this invention is to prevent the posture of a sheet discharged onto the discharge tray from being disturbed when the sheet is discharged, compared to a case in which the exhaust passages are not provided on the wall surface of the discharge tray and are inclined so as to widen toward the outside of both ends in the width direction intersecting the sheet discharge direction as they go downward on the wall surface. [Means for solving the problem]

[0009] The invention described in claim 1 is a discharge tray that stores discharged sheets by abutting an upstream end of the discharged sheet against a wall surface; a plurality of exhaust passages provided on a wall surface of the discharge tray, the exhaust passages being inclined so as to widen toward both ends of the wall surface along a width direction intersecting with a discharge direction of the sheet as the exhaust passages go downward; The sheet ejection device is provided with:

[0010] The invention described in claim 2 is the sheet ejection device according to claim 1, wherein the exhaust passages are provided symmetrically with respect to a reference position.

[0011] The invention described in claim 3 is the sheet discharging device according to claim 2, wherein the reference position is a center in a direction intersecting a discharging direction of the sheet.

[0012] The invention described in claim 4 is the sheet discharge device according to claim 2, wherein the plurality of exhaust passages are formed by convex portions or slit portions provided on a wall surface of the discharge tray.

[0013] The invention described in claim 5 is a sheet discharge device described in claim 1, wherein the discharge tray has an inclined surface formed so that the upstream end along the discharge direction of the sheet is the lowest.

[0014] The invention described in claim 6 is a sheet discharge device described in claim 5, in which the sheet is discharged by its own weight along the inclined surface of the discharge tray with the upstream end of the sheet along the discharge direction abutting against the wall surface.

[0015] The invention described in claim 7 includes an image forming means for forming an image on a sheet, a sheet discharge means for discharging the sheet on which the image is formed by the image forming means; Equipped with The image forming apparatus uses the sheet discharging device according to any one of claims 1 to 6 as the sheet discharging means. Effect of the Invention

[0016] According to the invention described in claim 1, it is possible to suppress disturbance of the posture of the sheet discharged onto the discharge tray when the sheet is discharged, compared to a case in which the exhaust passages are not provided on the wall surface of the discharge tray and are inclined so as to widen toward the outside of both ends in the width direction intersecting the sheet discharge direction as they go downward on the wall surface.

[0017] According to the invention recited in claim 2, the plurality of exhaust passages can effectively prevent the seat from being disturbed in position, compared to the case where the plurality of exhaust passages are provided in an asymmetrical shape.

[0018] According to the invention described in claim 3, it becomes easier to symmetrically regulate the sheet in the width direction, compared to a case where the reference position is other than the center in the direction intersecting the sheet discharge direction.

[0019] According to the invention described in claim 4, the multiple exhaust passages are easier to form than when they are formed by anything other than the convex portions or slit portions provided on the wall surface of the discharge tray.

[0020] According to the invention described in claim 5, the discharge tray can reliably align the sheet by abutting it against the wall surface, compared to a case in which the discharge tray does not have an inclined surface formed so that the upstream end in the discharge direction of the sheet is the lowest.

[0021] According to the invention described in claim 6, the configuration can be simplified compared to a case in which the sheet is struck against the wall surface of the discharge tray by a force other than its own weight.

[0022] According to the invention described in claim 7, it is possible to suppress the posture of the sheet discharged onto the discharge tray from being disturbed when the sheet is discharged, compared to when a sheet discharge device described in any of claims 1 to 6 is not used as a sheet discharge means. [Brief description of the drawings]

[0023] [Figure 1] 1 is an overall configuration diagram showing an image forming apparatus to which a sheet discharging device according to a first embodiment of the present invention is applied; [Diagram 2] 1 is a configuration diagram showing a main part of an image forming apparatus according to a first embodiment of the present invention; [Diagram 3] 1 is a perspective configuration diagram showing a main part of an image forming apparatus according to a first embodiment of the present invention; [Figure 4] FIG. 1 is a configuration diagram showing a conventional sheet discharging device. [Diagram 5] 1 is a perspective configuration diagram showing a sheet discharging device according to a first embodiment of the present invention; [Figure 6] FIG. 4 is a front view showing a wall surface of the sheet ejection device. [Figure 7] FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. [Figure 8] 1 is a perspective configuration diagram illustrating an operation of a sheet discharging device according to a first embodiment of the present invention; [Figure 9] FIG. 11 is a perspective configuration diagram showing a sheet discharging device according to a second embodiment of the present invention. [Figure 10] FIG. 4 is a front view showing a wall surface of the sheet ejection device. [Figure 11] 11 is a cross-sectional view taken along line XI-XI of FIG. 10. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0025] [Embodiment 1] 1 and 2 show an image forming apparatus to which a sheet discharge device according to embodiment 1 is applied. Fig. 1 shows an overview of the entire image forming apparatus, and Fig. 2 shows an enlarged view of the main parts (such as an imaging device) of the image forming apparatus.

[0026] <Overall configuration of image forming apparatus> The image forming apparatus 1 according to the first embodiment is configured as, for example, a color copier. The image forming apparatus 1 is provided with an image reading device 2 that reads an image of an original (not shown) at the upper end of the apparatus main body 1a. In addition to the function of copying the image of the original read by the image reading device 2, the image forming apparatus 1 also functions as a color printer or the like that records image information sent from a host computer (not shown) or the like.

[0027] The image forming apparatus 1 includes, inside the apparatus main body 1a, a plurality of image forming devices 10 that form toner images developed with toner constituting the developer 4, an intermediate transfer device 20 that holds the toner images formed by each image forming device 10 and transports them to a secondary transfer position where they are finally secondarily transferred onto a recording paper 5 as an example of a sheet, a paper feed device 50 that stores and transports the required recording paper 5 to be supplied to the secondary transfer position of the intermediate transfer device 20, and a fixing device 40 that fixes the toner image on the recording paper 5 that has been secondarily transferred by the intermediate transfer device 20. The plurality of image forming devices 10 and the intermediate transfer device 20 constitute an image forming means that forms an image on the recording paper 5. The apparatus main body 1a of the image forming apparatus 1 is formed of a supporting structure member, an exterior cover, etc.

[0028] The imaging device 10 is composed of four imaging devices 10Y, 10M, 10C, and 10K that are dedicated to forming toner images of four colors, yellow (Y), magenta (M), cyan (C), and black (K), respectively. These four imaging devices 10 (Y, M, C, and K) are arranged in a line in an inclined state in the internal space of the device main body 1a. Of the four imaging devices 10 (Y, M, C, and K), the yellow (Y) imaging device 10Y is located relatively high above along the vertical direction Z, and the black (K) imaging device 10K is located relatively low.

[0029] As shown in Figures 1 and 2, each of the yellow (Y), magenta (M), cyan (C) and black (K) image creating devices 10 (Y, M, C, K) is equipped with a rotating photosensitive drum 11 as an example of an image holding means for holding an electrostatic latent image, and around this photosensitive drum 11, various devices as examples of toner image forming means, such as the following, are mainly arranged. The main devices are a charging device 12 that charges the image-forming peripheral surface (image bearing surface) of the photosensitive drum 11 to a required potential, an exposure device 13 that irradiates the charged peripheral surface of the photosensitive drum 11 with light based on image information (signal) to form an electrostatic latent image (for each color) with a potential difference, developing devices 14 (Y, M, C, K) that develop the electrostatic latent image with toner of developer 4 of the corresponding color (Y, M, C, K) to form a toner image, primary transfer devices 15 (Y, M, C, K) that transfer each toner image to an intermediate transfer device 20, and drum cleaning devices 16 (Y, M, C, K) that remove and clean any toner and other deposits that remain on and adhere to the image bearing surface of the photosensitive drum 11 after the primary transfer.

[0030] The photoconductor drum 11 has an image bearing surface formed on the peripheral surface of a grounded cylindrical or columnar substrate, the peripheral surface of which has a photoconductive layer (photosensitive layer) made of a photosensitive material. The photoconductor drum 11 is supported so as to rotate in the direction indicated by the arrow A by power transmitted from a rotation drive device (not shown).

[0031] As shown in Fig. 2, the charging device 12 is composed of a contact-type charging roll 121 arranged in contact with the photoconductor drum 11. A cleaning roll 122 for cleaning the surface of the charging roll 121 is arranged on the rear side of the charging roll 121. A charging voltage is supplied to the charging roll 121 of the charging device 12. When the developing device 14 performs reversal development, the charging voltage is a voltage or current of the same polarity as the charging polarity of the toner supplied from the developing device 14. Note that the charging device 12 may be a non-contact charging device such as a scorotron arranged in a non-contact state with the surface of the photoconductor drum 11.

[0032] The exposure device 13 forms an electrostatic latent image by irradiating the charged peripheral surface of the photoconductor drum 11 with light configured according to image information input to the image forming apparatus 1. When it is time to form a latent image, image information (signals) input to the image forming apparatus 1 by any means is transmitted to the exposure device 13.

[0033] The exposure device 13 is an LED print head that forms an electrostatic latent image by irradiating the photoconductor drum 11 with light corresponding to image information using LEDs (Light Emitting Diodes) as a plurality of light emitting elements arranged along the axial direction of the photoconductor drum 11. Note that the exposure device 13 may be one that deflects and scans laser light configured according to the image information along the axial direction of the photoconductor drum 11.

[0034] Each of the developing devices 14 (Y, M, C, K) is configured by arranging a developing roll 141 that holds the developer and transports it to a developing area facing the photosensitive drum 11 inside a housing 140 in which an opening portion at a position facing the photosensitive drum 11 and a developer storage chamber are formed, an agitation supply member 142 made of a screw auger or the like that supplies the developer while stirring it so that it passes through the developing roll 141, an agitation transport member 143 made of a screw auger or the like that transports the developer to the agitation supply member 142 while stirring it, and a layer thickness regulating member 144 that regulates the amount (layer thickness) of the developer held on the developing roll 141. A developing voltage is supplied from a power supply device (not shown) between the developing roll 141 and the photosensitive drum 11 in this developing device 14. For example, a two-component developer containing a non-magnetic toner and a magnetic carrier is used as the four-color developer.

[0035] The primary transfer device 15 (Y, M, C, K) is a contact type transfer device equipped with a primary transfer roll that rotates in contact with the periphery of the photosensitive drum 11 via the intermediate transfer belt 21 and is supplied with a primary transfer voltage. As the primary transfer voltage, a DC voltage showing a polarity opposite to the charge polarity of the toner is supplied from a power supply device (not shown).

[0036] 2, the drum cleaning device 16 is composed of a container-shaped main body 160 with a portion open, a cleaning plate 161 that is arranged so as to come into contact with the peripheral surface of the photosensitive drum 11 after primary transfer with a required pressure to remove and clean residual toner and other deposits, and a sending member 162 such as a screw auger that collects the toner and other deposits removed by the cleaning plate 161 and conveys them to a collection system (not shown). A plate-shaped member (e.g., a blade) made of a material such as rubber is used as the cleaning plate 161.

[0037] 1, the intermediate transfer device 20 is disposed so as to be located above each of the image forming devices 10 (Y, M, C, K). The intermediate transfer device 20 is mainly composed of an intermediate transfer belt 21 that rotates in the direction indicated by the arrow B while passing through a primary transfer position between the photosensitive drum 11 and the primary transfer device 15 (primary transfer roll), a plurality of belt support rolls 22-25 that support the intermediate transfer belt 21 in a desired state from its inner surface and rotatably, a secondary transfer device 30 as an example of a secondary transfer member that is disposed on the outer peripheral surface (image bearing surface) side of the intermediate transfer belt 21 supported by the belt support roll 25 and secondarily transfers the toner image on the intermediate transfer belt 21 to the recording paper 5, and a belt cleaning device 26 that removes and cleans toner, paper powder, and other deposits that remain and adhere to the outer peripheral surface of the intermediate transfer belt 21 after passing through the secondary transfer device 30.

[0038] An endless belt made of a material in which a resistance adjusting agent such as carbon black is dispersed in a synthetic resin such as polyimide resin or polyamide resin is used as the intermediate transfer belt 21. The belt support roll 22 is configured as a drive roll that is rotated by a drive device (not shown), the belt support roll 23 is configured as a surface finishing roll that maintains the running position of the intermediate transfer belt 21, the belt support roll 24 is configured as a tension applying roll that applies tension to the intermediate transfer belt 21, and the belt support roll 25 is configured as a backup roll for secondary transfer.

[0039] 1, the secondary transfer device 30 is a contact type transfer device including a secondary transfer roll 31 that rotates in contact with the circumferential surface of the intermediate transfer belt 21 and is supplied with a secondary transfer voltage at a secondary transfer position, which is the outer circumferential surface portion of the intermediate transfer belt 21 supported by the belt support roll 25 in the intermediate transfer device 20. A DC voltage having the same polarity as or opposite to the charge polarity of the toner is supplied as the secondary transfer voltage to the secondary transfer roll 31 or the belt support roll 25 of the intermediate transfer device 20.

[0040] 2, the belt cleaning device 26 is composed of a container-shaped main body 260 with a portion open, a cleaning plate 261 that is arranged so as to come into contact with the peripheral surface of the intermediate transfer belt 21 after secondary transfer with a required pressure to remove and clean residual toner and other deposits, and a delivery member 262 such as a screw auger that collects the toner and other deposits removed by the cleaning plate 261 and conveys them to a recovery system (not shown). A plate-shaped member (e.g., a blade) made of a material such as rubber is used as the cleaning plate 261.

[0041] The fixing device 40 is configured by arranging a heating rotor 41 in the form of a drum or belt, which is heated by a heating means so that the surface temperature is maintained at a required temperature, and a pressure rotor 42 in the form of a drum or belt, which rotates in contact with the heating rotor 41 at a specified pressure in a state substantially along the axial direction of the heating rotor 41. An exit roll 43 is provided at the exit portion of the fixing device 40 to transport the recording paper 5 that has been subjected to the fixing process. In this fixing device 40, the contact portion where the heating rotor 41 and the pressure rotor 42 come into contact becomes a fixing processing portion where the required fixing process (heating and pressurization) is performed.

[0042] The paper feeder 50 is disposed so as to be located below the imaging devices 10 (Y, M, C, K) for yellow (Y), magenta (M), cyan (C), and black (K). This paper feeder 50 is mainly composed of a plurality (or a single) paper container 51 that stores recording paper 5 of a desired size, type, etc. in a stacked state, and feeders 52, 53 that feed the recording paper 5 one sheet at a time from the paper container 51. The paper container 51 is attached so that it can be pulled out, for example, from the front side (the side that the user faces during operation) of the main body 1a, or in the illustrated example, from the front side of the paper surface.

[0043] Examples of the recording paper 5 include plain paper, thin paper, and OHP sheets used in electrophotographic copiers, printers, etc. In order to further improve the smoothness of the image surface after fixing, it is preferable that the surface of the recording paper 5 is as smooth as possible, and for example, coated paper in which the surface of plain paper is coated with a resin or the like, or so-called thick paper with a relatively large basis weight such as art paper for printing can be used.

[0044] Between the paper feeder 50 and the secondary transfer device 30, there is provided a paper feed conveying path 56 including a plurality (or a single) of paper conveying roll pairs 54, 55 and a conveying guide (not shown) for conveying the recording paper 5 sent out from the paper feeder 50 to the secondary transfer position. The paper conveying roll pair 55 is configured as, for example, a registration roll for adjusting the conveying timing of the recording paper 5. In addition, at the upper portion along the vertical direction Z of the fixing device 40, there is provided a paper discharge conveying section 58 including first to fourth paper discharge conveying paths 57a to 57d for discharging the recording paper 5 sent out from the exit roll 43 of the fixing device 40 after fixing to a sheet discharge device 60 as an example of a sheet discharge means provided at the upper portion of the device main body 1a.

[0045] The sheet discharge device 60 includes first and second discharge trays 61 and 62 of a so-called internal discharge type provided on the upper portion of the device main body 1a, and a third discharge tray 63 provided toward the outside on a side (left side in the drawing) of the paper discharge conveyance section 58. Inside the paper discharge conveyance section 58, there are provided a first paper discharge conveyance path 57a branching off from the second paper discharge conveyance path 57b and including a first paper discharge roll pair 64 for discharging the recording paper 5 to the first discharge tray 61, a third paper discharge conveyance path 57c branching off from the second paper discharge conveyance path 57b and including a second paper discharge roll pair 66 for discharging the recording paper 5 to the second discharge tray 62, and a fourth paper discharge conveyance path 57d branching off from the third paper discharge conveyance path 57c and including a third paper discharge roll pair 67 for discharging the recording paper 5 to the third discharge tray 63.

[0046] 1, reference numeral 68 denotes a pair of paper transport rolls provided in the middle of the second paper discharge transport path 57b, G1 denotes a first switching gate that branches the first paper discharge transport path 57a and the second paper discharge transport path 57b, and G2 denotes a second switching gate that branches the third paper discharge transport path 57c and the fourth paper discharge transport path 57d. The sheet discharge device 60 will be described in detail later.

[0047] Inside the device main body 1a, as shown in FIG. 2, there is provided a double-sided transport path 70 equipped with a paper transport roll pair 69 that flips the recording paper 5 with an image formed on one side thereof and transports it again to the paper transport roll pair 55 by switching the rotation direction of the first paper discharge roll pair 64 from the forward direction to the reverse direction while the recording paper 5 with an image formed on one side is held by the first paper discharge roll pair 64.

[0048] In Figure 1, symbol 71 indicates a manual feed tray that is provided on the side (left side in the figure) of the device body 1a of the image forming device 1 so as to be able to be opened and closed freely, and between the manual feed tray 71 and the pair of paper transport rolls 55, there is provided an output device 72 that sends out the recording paper 5 stored in the manual feed tray 71 one sheet at a time, and a manual feed paper transport path 74 that is composed of a pair of paper transport rolls 73 and a transport guide (not shown), etc.

[0049] In addition, the reference numerals 145 (Y, M, C, K) in FIG. 1 each indicate a toner cartridge arranged in a direction perpendicular to the paper surface, each cartridge containing developer including at least toner to be supplied to the corresponding developing device 14 (Y, M, C, K).

[0050] 1 indicates a control device that comprehensively controls the operation of the image forming apparatus 1. The control device 100 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), or a bus for connecting the CPU, the ROM, etc., a communication interface, etc. (not shown).

[0051] <Operation of the image forming device> Hereinafter, a basic image forming operation by the image forming apparatus 1 will be described.

[0052] Here, an operation of forming a full-color image by combining toner images of four colors (Y, M, C, K) using the four image forming devices 10 (Y, M, C, K) will be described.

[0053] When the control device 100 of the image forming apparatus 1 receives command information requesting an image forming operation (printing), the four image forming devices 10 (Y, M, C, K), the intermediate transfer device 20, the secondary transfer device 30, the fixing device 40, etc. start up.

[0054] In each imaging device 10 (Y, M, C, K), first, each photoconductor drum 11 rotates in the direction indicated by arrow A, and each charging device 12 charges the surface of each photoconductor drum 11 to a required polarity (negative polarity in the first embodiment) and potential. Next, exposure device 13 irradiates the surface of the charged photoconductor drum 11 with light emitted based on an image signal obtained by converting image information input to image forming device 1 into each color component (Y, M, C, K), and forms an electrostatic latent image of each color component composed of a required potential difference on the surface.

[0055] Next, each image forming device 10 (Y, M, C, K) develops the electrostatic latent image of each color component formed on the photoconductor drum 11 by supplying toner of the corresponding color (Y, M, C, K) charged to the required polarity (negative polarity) from the developing roll 141 and electrostatically attaching it to the electrostatic latent image of each color component. Through this development, the electrostatic latent image of each color component formed on each photoconductor drum 11 is visualized as a toner image of four colors (Y, M, C, K) developed with the toner of the corresponding color.

[0056] Next, when the toner images of each color formed on the photosensitive drum 11 of each image creating device 10 (Y, M, C, K) are transported to the primary transfer position, the primary transfer device 15 (Y, M, C, K) performs primary transfer of the toner images of each color in such a manner that they are superimposed in order onto the intermediate transfer belt 21 rotating in the direction indicated by arrow B of the intermediate transfer device 20.

[0057] In addition, in each of the imaging devices 10 (Y, M, C, K) where the primary transfer has been completed, the drum cleaning device 16 scrapes off any adhering matter to clean the surface of the photosensitive drum 11. This makes each of the imaging devices 10 (Y, M, C, K) ready for the next image formation operation.

[0058] Next, the intermediate transfer device 20 conveys the primary transferred toner image to the secondary transfer position by the rotation of the intermediate transfer belt 21. Meanwhile, the paper feeder 50 sends out the required recording paper 5 to the paper feed path 56 in accordance with the image creation operation. In the paper feed path 56, a pair of paper feed rolls 55 as registration rolls sends out and supplies the recording paper 5 to the secondary transfer position in accordance with the transfer timing.

[0059] At the secondary transfer position, the secondary transfer roll 31 of the secondary transfer device 30 performs secondary transfer of the toner images on the intermediate transfer belt 21 all at once onto the recording paper 5. In the intermediate transfer device 20 where the secondary transfer is completed, the belt cleaning device 26 removes and cleans the surface of the intermediate transfer belt 21 to remove any adhering matter such as toner remaining thereon after the secondary transfer.

[0060] Next, the recording paper 5 onto which the toner image has been secondarily transferred is peeled off from the intermediate transfer belt 21 and the secondary transfer roll 31, and then conveyed to the fixing device 40. In the fixing device 40, the recording paper 5 after the secondary transfer is introduced and passed through a contact portion between a rotating heating rotator 41 and a pressure applying rotator 42, whereby the necessary fixing process (heating and pressurizing) is performed to fix the unfixed toner image onto the recording paper 5. Finally, in the case of an image forming operation in which an image is only formed on one side of the recording paper 5 after fixing, the recording paper 5 after fixing is discharged via the first to fourth paper discharge conveying paths to any one of the first to third discharge trays 61 to 63 installed at the top of the device main body 1a.

[0061] When forming an image on both sides of the recording paper 5, the recording paper 5 with an image formed on one side is not discharged to the first discharge tray 61 by the first paper discharge roll pair 64, but the rotation direction of the first paper discharge roll pair 64 is switched to the reverse direction while the first paper discharge roll pair 64 is holding the rear end of the recording paper 5. The recording paper 5 transported in the reverse direction by the first paper discharge roll pair 64 is transported to a double-sided transport path 70 equipped with a paper transport roll pair 69 and the like, and is transported again to the paper transport roll pair 55 in a reversed state. The paper transport roll pair 55 sends out and supplies the recording paper 5 to a secondary transfer position in accordance with the transfer timing, forms an image on the back side of the recording paper 5, and discharges the recording paper 5 with the image fixed on the back side to one of the first to third discharge trays 61 to 63 installed at the top of the device main body 1a via one of the first to fourth paper discharge transport paths 57a to 57d.

[0062] By the above operation, a recording sheet 5 is outputted, on one or both sides of which a full-color image formed by combining four color toner images is formed.

[0063] <Configuration of the sheet ejection device> As shown in FIG. 2, the image forming apparatus 1 is provided with a sheet discharge device 60 for discharging recording paper 5, which is an example of a sheet having an image formed on one or both sides, at an upper portion of the apparatus main body 1a.

[0064] The sheet discharge device 60 according to the first embodiment is configured as a so-called internal discharge type sheet discharge device that discharges the recording paper 5 into the inside of the body, which is the upper part of the device body 1a of the image forming device 1.

[0065] As shown in Figures 2 and 3, the sheet discharge device 60 is equipped with first to third discharge trays 61 to 63 that store the recording paper 5, which has an image fixed by the fixing device 40 and is discharged, by abutting its upstream end in the discharge direction against a wall, and first to third paper discharge roll pairs 64, 66, and 67 that discharge the recording paper 5, which has an image fixed by the fixing device 40, into the first to third discharge trays 61 to 63.

[0066] Here, a first discharge tray 61 having a first paper discharge roll pair 64 will be particularly described as the sheet discharge device 60.

[0067] As described above, the first discharge tray 61 is configured as a so-called internal discharge type discharge tray that discharges the recording paper 5 into the body of the device body 1a of the image forming device 1. As shown in Fig. 2 and Fig. 3, the first discharge tray 61 includes an inclined portion 611 as an example of an inclined surface inclined so that its upstream end along the discharge direction is located inside the device body 1a, a flat portion 612 arranged on the downstream side of the inclined portion 611 along the discharge direction and formed flat along the horizontal direction X, and a wall surface 613 arranged on the upstream end of the inclined portion 611 along the discharge direction and slightly inclined so that its lower end along the vertical direction Z is located downstream along the discharge direction, against which the upstream end along the discharge direction of the recording paper 5 discharged to the first discharge tray 61 abuts and is aligned.

[0068] The first discharge tray 61 has both ends of its inclined portion 611 in a width direction (depth direction) Y that intersects with the discharge direction of the recording paper 5, and is closed by front and rear side surfaces 1b and 1c that constitute the device body 1a. In Fig. 2, reference numeral 1d denotes an air outlet that opens in the side surface 1c of the device body 1a.

[0069] At the upstream end of the first discharge tray 61 in the discharge direction of the recording paper 5, as shown in Figures 2 and 3, a first paper discharge roll pair 64 is provided at a height approximately equal to the flat portion 612 of the first discharge tray 61, which discharges the recording paper 5 diagonally upward onto the first discharge tray 61.

[0070] In the sheet discharge device 60 configured as described above, as shown in Figures 4(a) and (b), when the recording paper 5 is discharged onto the first discharge tray 61 by the first paper discharge roll pair 64, both sides of the inclined portion 611 of the first discharge tray 61 along the width direction intersecting with the discharge direction are blocked by the sides 1b and 1c of the device main body 1a, so that as the recording paper 5 is discharged (moved), air located below the recording paper 5 exists as a spiral air pocket 75. Note that Figure 4 is a schematic view of an image taken with the front cover (not shown) of the image forming apparatus 1 open in order to observe the attitude of the recording paper 5 discharged onto the first discharge tray 61.

[0071] Therefore, due to the presence of the air pocket 75, the recording paper 5 discharged onto the first discharge tray 61 does not immediately fall onto the first discharge tray 61 but temporarily floats in mid-air. Then, in the first discharge tray 61, the air constituting the air pocket 75 below the recording paper 5 moves to the periphery of the first discharge tray 61, causing the recording paper 5 to fall onto the surface of the inclined portion 611 of the first discharge tray 61 under its own weight.

[0072] As a result, in the conventional sheet discharge device 60 configured as described above, as shown in FIG. 4(b), when the recording paper 5 is discharged to the first discharge tray 61, the posture of the recording paper 5 becomes unstable and disturbed due to the influence of the air pocket 75 present below the recording paper 5, and the upstream end of the recording paper 5 in the discharge direction comes into contact with the wall surface 613 of the first discharge tray 61 and remains in a curved state, a condition known as a "bank residue."

[0073] Therefore, in order to prevent the posture of the sheet discharged onto the discharge tray from being disturbed when the sheet is discharged, the sheet discharge device of this embodiment 1 is configured to have a plurality of exhaust passages provided on the wall of the discharge tray and inclined so as to widen outwardly toward both ends along the width direction intersecting with the sheet discharge direction as it moves downward on the wall.

[0074] Furthermore, in the sheet discharge device according to the first embodiment, a plurality of exhaust passages are provided symmetrically with respect to a reference position, and the reference position is configured to be, for example, the center of a direction intersecting with the sheet discharge direction.

[0075] That is, in the sheet discharge device 60 according to the first embodiment, as shown in Fig. 5, a plurality of exhaust passages 80, 80... are provided on a wall surface 613 of a first discharge tray 61. As shown in Figs. 6 and 7, a plurality of ribs 81, 81... which are linear convex portions for forming the plurality of exhaust passages 80, 80... are integrally formed on the wall surface 613 of the first discharge tray 61 so as to protrude from the inner surface of the wall surface 613 toward the inside of the first discharge tray 61.

[0076] 6, the multiple ribs 81, 81... are provided symmetrically with respect to a reference position C. The reference position for providing the ribs 81, 81... is configured to be, for example, the center of the width direction intersecting with the discharge direction of the recording paper 5.

[0077] To explain further, as shown in Figures 6 and 7, the multiple ribs are arranged parallel to each other on the wall surface 613 of the first discharge tray 61, with a reference position C that is the center of the width direction intersecting the discharge direction of the recording paper 5 as a reference, so that they have a left-right symmetrical shape, and are inclined at an angle θ with respect to the vertical direction Z so that they spread outward toward both ends in the width direction intersecting the discharge direction of the recording paper 5 as they go downward along the wall surface 613.

[0078] The multiple ribs 81, 81... are formed in an elongated convex shape having a required width and height relative to the wall surface 613 of the first discharge tray 61. Among the multiple ribs 81, 81..., a multiple number of exhaust passages 80, 80... are provided between adjacent ribs 81, 81... as spaces separated between the adjacent ribs 81, 81....

[0079] The multiple exhaust passages 80, 80..., like the multiple ribs 81, 81..., are arranged at an incline so that they widen outward toward both ends along the width direction that intersects with the discharge direction of the recording paper 5 as they proceed downward along the vertical direction Z of the wall surface 613.

[0080] The multiple exhaust passages 80, 80... are set so that the cross-sectional area of ​​each exhaust passage 80, 80... is larger as the height of the multiple ribs 81, 81... is higher and the spacing between the multiple ribs 81, 81... is larger. Conversely, the multiple exhaust passages 80, 80... are set so that the cross-sectional area of ​​each exhaust passage 80, 80... is smaller as the height of the multiple ribs 81, 81... is lower and the spacing between the multiple ribs 81, 81... is smaller.

[0081] However, the combined cross-sectional area of ​​the multiple exhaust passages 80, 80... is determined by the product of the cross-sectional area of ​​each exhaust passage 80, 80... and the total number of exhaust passages 80, 80....

[0082] In the above-described configuration, the sheet discharge device of embodiment 1 is capable of preventing the posture of the sheet discharged onto the discharge tray from being disturbed when the sheet is discharged, compared to a case in which the device does not have multiple exhaust passages that are provided on the wall surface of the discharge tray and inclined so as to widen toward the outside of both ends in the width direction intersecting the sheet discharge direction as they go downward on the wall surface, as follows.

[0083] That is, in the sheet discharge device 60 according to the first embodiment, as shown in FIG. 1, the recording paper 5 having an image formed on one or both sides is discharged to one of the first to third discharge trays 61 to 63.

[0084] At this time, in the sheet discharge device 60, as shown in Figure 4 (a), when the recording paper 5 with an image formed on one or both sides is discharged to the first discharge tray 61, the recording paper 5 with an image formed on one or both sides is discharged by the first paper discharge roll pair 64 so that it is approximately parallel to the flat portion 612 of the first discharge tray 61.

[0085] At that time, depending on various factors such as the fixing characteristics of the fixing device 40, the water absorption characteristics of the recording paper 5, or the state of the image formed on the recording paper 5, the recording paper 5 may develop a curve such as a down curl in a convex shape toward the first discharge tray 61, or an upper curl in a concave shape toward the first discharge tray 61.

[0086] In the sheet discharge device 60, immediately after the recording paper 5 is discharged onto the first discharge tray 61, an air pocket 75 in which air remains is present below the recording paper 5.

[0087] 5, in the sheet discharge device 60 according to the first embodiment, a plurality of exhaust passages 80, 80... are provided on a wall surface 613 that is an end portion on the upstream side along the discharge direction of the recording paper 5 of the first discharge tray 61. The plurality of exhaust passages 80, 80... are inclined so as to widen outwardly toward both ends in the width direction intersecting with the discharge direction of the recording paper 5 as they approach downward of the wall surface 613 of the first discharge tray 61.

[0088] Therefore, when the recording paper 5 is discharged onto the first discharge tray 61, as shown in Figure 8, the air that constitutes the air pocket 75 below the recording paper 5 can quickly escape toward the top of the first discharge tray 61 through multiple exhaust passages 80, 80... provided at the upstream end of the first discharge tray 61 in the discharge direction of the recording paper 5.

[0089] At this time, the multiple exhaust passages 80, 80... are provided in an inclined state so as to widen toward the outside of both ends in the width direction intersecting with the discharge direction of the recording paper 5 as they go downwardly below the wall surface 613 of the first discharge tray 61. Therefore, the recording paper 5 discharged onto the first discharge tray 61 is guided so that its upstream end along the discharge direction comes into contact with the surfaces of the multiple ribs 81, 81... and widens toward the outside of both ends in the width direction intersecting with the discharge direction along the inclination of the multiple ribs 81, 81...

[0090] As a result, even if the recording paper 5 discharged onto the first discharge tray 61 has a curve such as a down curl or an upper curl, the recording paper 5 comes into contact with the multiple ribs 81, 81, etc. so as to expand toward both ends along its width direction, and is discharged with the curve corrected.

[0091] In this way, in the sheet discharge device 60 of this embodiment 1, it is possible to prevent the posture of the recording paper 5 discharged into the first discharge tray 61 from being disturbed when the recording paper 5 is discharged, compared to a case where the sheet discharge device 60 does not have multiple exhaust passages 80, 80..., which are provided on the wall surface 613 of the first discharge tray 61 and are inclined so as to widen toward the outside of both ends in the width direction intersecting the discharge direction of the recording paper 5 as they go downward of the wall surface 613.

[0092] Embodiment 2 9 is a perspective view showing an image forming apparatus to which a sheet discharge device according to the second embodiment of the present invention is applied. In addition, the same reference numerals are used to designate members corresponding to those in the first embodiment.

[0093] That is, as shown in Figures 9 to 11, the sheet discharge device 60 of embodiment 2 is configured so that the multiple exhaust passages 80, 80... are not formed by protrusions provided on the wall surface 613 of the first discharge tray 61, but by slit portions that are directly opened in the wall surface 613 of the first discharge tray 61 in a shape corresponding to the multiple exhaust passages 80, 80....

[0094] The wall surface 613 of the first discharge tray 61 is provided with a plurality of exhaust passages 80, 80... consisting of inclined slit portions which widen outwardly toward both ends along the width direction which intersects with the discharge direction of the recording paper 5 as they go downward in the vertical direction Z of the wall surface 613.

[0095] The plurality of exhaust passages 80, 80... are formed, for example, by integral molding when molding the member that constitutes the wall surface 613 of the first discharge tray 61.

[0096] The area of ​​the wall surface 613 of the first discharge tray 61 existing between the multiple exhaust passages 80, 80... may be configured to be flush with the surface of the wall surface 613, but in order to reduce the contact resistance with the recording paper 5, it is desirable to make it have a rib shape protruding from the surface of the wall surface 613, as in embodiment 1.

[0097] In the sheet discharge device 60 according to the second embodiment, when the recording paper 5 is discharged onto the first discharge tray 61, the air constituting the air pocket 75 below the recording paper 5 escapes to the inside of the device body 1a via the multiple exhaust passages 80, 80.... Therefore, unlike the first embodiment, the air flowing through the multiple exhaust passages 80, 80... does not flow from below to above in the vertical direction Z along the longitudinal direction of the multiple exhaust passages 80, 80..., but flows from the front surface to the back surface (inner surface) of the wall surface 613 of the first discharge tray 61 via the multiple exhaust passages 80, 80..., making it possible to more quickly release the air constituting the air pocket 75 below the recording paper 5.

[0098] The other configurations and operations are the same as those of the first embodiment, and therefore the description thereof will be omitted.

[0099] In the above embodiment, a full-color image forming apparatus has been described; however, the sheet discharge device of the present invention is not limited to this, and can of course be similarly applied to monochrome image forming apparatuses, and can also be similarly applied to finishers that bind sheets or perform punching processes, etc., other than image forming apparatuses.

[0100] (Additional Note) (((1))) a discharge tray that stores the discharged sheet by abutting an upstream end of the discharged sheet against a wall surface; a plurality of exhaust passages provided on a wall surface of the discharge tray, the exhaust passages being inclined so as to widen toward both ends of the wall surface along a width direction intersecting with a discharge direction of the sheet as the exhaust passages go downward; A sheet ejection device comprising: (((2))) The sheet ejection device according to (((1))), wherein the plurality of exhaust passages are provided symmetrically with respect to a reference position. (((3))) The sheet discharging device according to (((2))), wherein the reference position is the center in a direction intersecting a discharging direction of the sheet. (((4))) The sheet discharge device according to (((2))), wherein the plurality of exhaust passages are formed by a convex portion or a slit portion provided on a wall surface of the discharge tray. (((5))) The sheet ejection device according to (((1))), wherein the ejection tray has an inclined surface formed so that the end portion on the upstream side in the ejection direction of the sheets is the lowest. (((6))) A sheet discharge device described in any one of (((1))) to (((5))), in which the sheet is discharged by its own weight along the inclined surface of the discharge tray with the upstream end of the sheet in the discharge direction abutting against the wall surface. (((7))) an image forming means for forming an image on a sheet; a sheet discharge means for discharging the sheet on which the image is formed by the image forming means; Equipped with An image forming apparatus using the sheet discharging device according to any one of ((1)) to (((6))) as the sheet discharging means.

[0101] The sheet discharge device according to (((1))) can prevent the posture of the sheet discharged onto the discharge tray from being disturbed when the sheet is discharged, compared to a case in which the device does not have multiple exhaust passages that are provided on the wall surface of the discharge tray and inclined so as to widen toward the outside of both ends in the width direction that intersects with the sheet discharge direction as they go downward on the wall surface. According to the sheet discharge device of (((2))), the multiple exhaust passages can effectively prevent the sheet from being out of position, compared to a case in which the multiple exhaust passages are provided in an asymmetric shape. According to the sheet discharge device of (((3))), it becomes easier to symmetrically regulate the sheet in the width direction, compared to when the reference position is other than the center in the direction intersecting the sheet discharge direction. According to the sheet discharge device of (((4))), the formation of the multiple exhaust passages is easier than when the exhaust passages are formed from anything other than the convex portions or slit portions provided on the wall surface of the discharge tray. According to the sheet discharge device of (((5))), the discharge tray can abut the sheet against the wall surface and reliably align it, compared to a case in which the discharge tray does not have an inclined surface with the upstream end in the discharge direction of the sheet formed at the lowest position. According to the sheet discharge device of (((6))), the structure can be simplified compared to a case in which the sheet is struck against the wall of the discharge tray by a force other than its own weight. According to the image forming apparatus of (((7))), it is possible to prevent the posture of the sheet discharged onto the discharge tray from being disturbed when the sheet is discharged, compared to a case in which a sheet discharge device described in any of (((1))) to (((6))) is not used as a sheet discharge means. [Explanation of symbols]

[0102] 1...Image forming device 60...Sheet ejection device 61…First output tray 611…Slope part 612...Flat area 613…Wall 80…Exhaust passage 81...Rib

Claims

1. a discharge tray that stores the discharged sheet by abutting an upstream end of the discharged sheet against a wall surface; a plurality of exhaust passages provided on a wall surface of the discharge tray, the exhaust passages being inclined so as to widen toward both ends of the wall surface along a width direction intersecting with a discharge direction of the sheet as the exhaust passages go downward; A sheet ejection device comprising:

2. 2. The sheet ejection device according to claim 1, wherein the plurality of exhaust passages are provided symmetrically with respect to a reference position.

3. The sheet discharging device according to claim 2 , wherein the reference position is a center in a direction intersecting a discharging direction of the sheet.

4. The sheet ejection device according to claim 2 , wherein the plurality of exhaust passages are formed by convex portions or slit portions provided on a wall surface of the ejection tray.

5. 2. The sheet ejection device according to claim 1, wherein the ejection tray has an inclined surface formed so that an end portion on an upstream side in the ejection direction of the sheets is the lowest.

6. The sheet ejection device according to claim 5 , wherein the sheet is ejected by its own weight along the inclined surface of the ejection tray in a state where an upstream end of the sheet in the ejection direction abuts against the wall surface.

7. an image forming means for forming an image on a sheet; a sheet discharge means for discharging the sheet on which the image is formed by the image forming means; Equipped with 7. An image forming apparatus using the sheet discharging device according to claim 1 as said sheet discharging means.

Images