Sheet discharge device and image forming apparatus

Abstract

A sheet discharge device and an image forming apparatus are provided, the sheet discharge device including: a discharge tray that accommodates a discharged sheet in such a manner that an end portion of an upstream side in a discharge direction thereof is in contact with a wall surface; and a plurality of exhaust passages provided on the wall surface of the discharge tray and inclined so as to extend toward the outside of both ends in the width direction intersecting the discharge direction of the sheet as the exhaust passages tend below the wall surface.

Description

Technical Field

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

[0002] Conventionally, as a technology related to the sheet discharge device, for example, technologies disclosed in Patent Documents 1 to 4 have been proposed.

[0003] Patent document 1 proposes a sheet discharge device, which comprises: a discharge component that discharges paper; a paper loading portion that loads the paper discharged by the discharge component; a rear end limiting component that limits the rear end position of the paper loaded on the paper loading portion; and an exhaust mechanism that discharges air from a corner of a reference surface facing the rear end limiting component and a paper loading surface of the paper loading portion.

[0004] Patent document 2 proposes a sheet discharge device, which comprises: a discharge wall portion, in which a discharge port is formed; a discharge roller, for discharging the delivered sheet from the discharge port; a sheet loading portion, for loading the sheet discharged and dropped from the discharge port; a suction portion, which opens between the discharge port in the discharge wall portion and the sheet loading portion, and sucks the air under the sheet discharged from the discharge port; and a control portion, for controlling the suction action performed by the suction portion, the control portion controlling the suction portion so that the suction portion starts the suction action at the moment when the rear end of the sheet discharged from the discharge port is separated from the discharge port, and stops the suction action at the moment when a predetermined time has passed.

[0005] Patent document 3 proposes a sheet discharge device, wherein a paper discharge tray comprises: a tray, which is slightly separated downward from the paper discharge mechanism and installed on the side of the image forming device body to receive and store the image-formed paper discharged by the paper discharge mechanism arranged on the image forming device body; and side walls, which are arranged between the upper surface of the tray and a position slightly above the paper discharge mechanism over the entire length of both sides of the tray, in the paper discharge tray, the side walls on both sides of the paper discharge tray are arranged to extend in the vertical direction and have a serrated convex-concave surface with a width in the horizontal direction of the inclined surface being longer on the upstream side in the paper discharge direction than on the downstream side, and air holes are arranged on its wall surface over almost the entire height.

[0006] Patent document 4 proposes a sheet discharge device, wherein a full detection component is capable of moving according to the loading height in order to detect the loading height of the paper on a paper discharge tray on which the paper is conveyed and loaded, and the full detection component has a contact surface portion that is contacted by the front end of the conveyed paper, and a detection portion that is located on the downstream side of the contact surface portion in the conveying direction and can contact the topmost layer of the paper loaded on the paper discharge tray, and a hole having an inclined edge portion inclined relative to the conveying direction of the paper is formed on the contact surface portion.

[0007] Patent Document 1: Japanese Patent Application Publication No. 2009-078873

[0008] Patent Document 2: Japanese Patent Application Publication No. 2015-212194

[0009] Patent Document 3: Japanese Patent No. 2896245

[0010] Patent Document 4: Japanese Patent Application Publication No. 2020-142915 Summary of the invention

[0011] An object of the present invention is to suppress the disorder of the posture of sheets discharged onto a discharge tray when the sheets are discharged, compared to a case where there are no multiple exhaust passages arranged on the wall of the discharge tray and inclined in a manner that expands outwardly at both end portions in the width direction intersecting the discharge direction of the sheets as they approach the bottom of the wall.

[0012] The invention described in claim 1 is a sheet discharging device comprising:

[0013] a discharge tray for accommodating discharged sheets in such a manner that an end portion on the upstream side along the discharge direction thereof abuts against a wall surface; and

[0014] A plurality of exhaust passages are provided on a wall surface of the discharge tray and are inclined so as to expand toward outer sides of both ends along a width direction intersecting with a discharge direction of the sheets as they go downwardly toward the wall surface.

[0015] The invention described in claim 2 is the sheet discharge device described in claim 1, wherein the plurality of exhaust passages are provided in a symmetrical shape with the reference position as the center.

[0016] The invention described in claim 3 is the sheet discharge device described in claim 2, wherein the reference position is a center in a direction intersecting with a discharge direction of the sheet.

[0017] The invention described in claim 4 is the sheet discharge device described in 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.

[0018] The invention described in claim 5 is the sheet discharge device described in claim 1, wherein the discharge tray has an inclined surface whose end portion on the upstream side along the discharge direction of the sheet is formed lowest.

[0019] The invention described in Scheme 6 is a sheet discharge device according to any one of Schemes 1 to 5, wherein the sheet is discharged along the inclined surface of the discharge tray under the action of its own weight in a state in which the end on the upstream side along the discharge direction of the sheet abuts against the wall surface.

[0020] The invention described in claim 7 is an image forming apparatus comprising:

[0021] An image forming mechanism that forms an image on a sheet; and

[0022] a sheet discharging mechanism for discharging the sheet on which the image is formed by the image forming mechanism,

[0023] As the sheet discharging mechanism, the sheet discharging device according to any one of aspects 1 to 6 is used.

[0024] Effects of the Invention

[0025] According to the first scheme of the present invention, compared with a case where there are no multiple exhaust passages arranged on the wall surface of the discharge tray and inclined in a manner that expands toward the outside of both end portions in the width direction intersecting the discharge direction of the sheet as they tend to the bottom of the wall surface, it is possible to suppress the posture disorder of the sheets discharged onto the discharge tray when the sheets are discharged.

[0026] According to the second aspect of the present invention, compared with the case where the plurality of exhaust passages are provided in an asymmetrical shape, it is possible to effectively suppress the posture disorder of the sheet.

[0027] According to the third aspect of the present invention, compared with a case where the reference position is located at a position other than the center in a direction intersecting the sheet discharge direction, it is easier to restrict the sheet symmetrically in the width direction.

[0028] According to the fourth aspect of the present invention, the exhaust passages can be easily formed compared to a case where the plurality of exhaust passages are formed by other than the convex portions or the slit portions provided on the wall surface of the discharge tray.

[0029] According to the fifth aspect of the present invention, compared with a case where the discharge tray does not have a sloped surface formed lowest at the upstream end portion along the sheet discharge direction, the sheets can be reliably aligned by contacting the wall surface.

[0030] According to the sixth aspect of the present invention, the structure can be simplified compared to a case where the sheet comes into contact with the wall surface of the discharge tray due to a force other than its own weight.

[0031] According to the seventh aspect of the present invention, compared with a case where the sheet discharge device described in any one of the first to sixth aspects of the present invention is not used as a sheet discharge mechanism, it is possible to suppress the posture disorder of the sheets discharged onto the discharge tray when discharging the sheets. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Embodiments of the present invention will be described in detail with reference to the following drawings.

[0033] Figure 1 is a diagram showing the overall configuration of an image forming apparatus to which a sheet discharge device according to Embodiment 1 of the present invention is applied;

[0034] Figure 2 is a structural diagram showing a main part of an image forming apparatus according to Embodiment 1 of the present invention;

[0035] Figure 3 is a perspective structural diagram showing a main part of an image forming apparatus according to Embodiment 1 of the present invention;

[0036] Figure 4 is a structural diagram showing a conventional sheet discharging device;

[0037] Figure 5 is a perspective structural diagram showing a sheet discharge device according to Embodiment 1 of the present invention;

[0038] Figure 6 is a front structural diagram showing a wall surface of a sheet discharge device;

[0039] Figure 7 is along Figure 6 A cross-sectional view taken along line VII-VII;

[0040] Figure 8 is a perspective structural diagram showing the function of the sheet discharge device according to the first embodiment of the present invention;

[0041] Fig. 9 is a perspective structural diagram showing a sheet discharge device according to a second embodiment of the present invention;

[0042] Fig.10 is a front structural diagram showing a wall surface of a sheet discharge device;

[0043] Fig.11 is along Fig.10 A cross-sectional view taken along line XI-XI.

[0044] Explanation of symbols

[0045] 1-image forming device, 60-sheet discharge device, 61-first discharge tray, 611-inclined portion, 612-flat portion, 613-wall surface, 80-exhaust passage, 81-rib. DETAILED DESCRIPTION

[0046] Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “embodiment”) will be described with reference to the drawings.

[0047] [Implementation Method 1]

[0048] Figure 1 and Figure 2 This is a diagram showing an image forming apparatus to which the sheet discharge device according to the first embodiment is applied. Figure 1 shows the overall outline of the image forming apparatus, Figure 2The main parts of the image forming apparatus (such as the image generating device) are shown in an enlarged manner.

[0049] <Overall Structure of Image Forming Apparatus>

[0050] The image forming apparatus 1 according to the first embodiment is configured as, for example, a color copier. The image forming apparatus 1 includes an image reading device 2 for reading an image of a document (not shown) at the upper end of an apparatus body 1a. The image forming apparatus 1 not only copies the image of the document read by the image reading device 2, but also functions as a color printer or the like for recording image information sent from a host computer or the like (not shown).

[0051] The image forming apparatus 1 includes, inside the apparatus body 1a, a plurality of image forming apparatuses 10 for forming toner images developed with toner constituting the developer 4; an intermediate transfer apparatus 20 for holding the toner images formed by the respective image forming apparatuses 10 and finally conveying them to a secondary transfer position for secondary transfer to a recording paper 5 as an example of a sheet; a paper feeder 50 for accommodating and conveying the required recording paper 5 to be supplied to the secondary transfer position of the intermediate transfer apparatus 20; and a fixing apparatus 40 for fixing the toner images on the recording paper 5 secondary transferred by the intermediate transfer apparatus 20, etc. The plurality of image forming apparatuses 10 and the intermediate transfer apparatus 20 constitute an image forming mechanism for forming an image on the recording paper 5. In addition, the apparatus body 1a of the image forming apparatus 1 is formed by a supporting structural member, an exterior cover, and the like.

[0052] The image generating device 10 is composed of four image generating devices 10Y, 10M, 10C, and 10K that are specialized in forming toner images of four colors, namely yellow (Y), magenta (M), cyan (C), and black (K). These four image generating devices 10 (Y, M, C, and K) are arranged in a row in an inclined state in the internal space of the device body 1a. Among the four image generating devices 10 (Y, M, C, and K), the image generating device 10Y for yellow (Y) is located at a relatively high position in the upper part along the vertical direction Z, and the image generating device 10K for black (K) is located at a relatively low position.

[0053] like Figure 1 and Figure 2As shown, each image generating device 10 (Y, M, C, K) of yellow (Y), magenta (M), cyan (C) and black (K) has a rotating photosensitive drum 11 as an example of an image holding mechanism for holding an electrostatic latent image, and each device as an example of the following colorant image forming mechanism is mainly arranged around the photosensitive drum 11. The main devices are a charging device 12 for charging the image-forming peripheral surface (image holding surface) of the photosensitive drum 11 to a required potential, an exposure device 13 for irradiating 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) having a potential difference, a developing device 14 (Y, M, C, K) for developing the electrostatic latent image with a toner of a developer 4 of a corresponding color (Y, M, C, K) to form a toner image, a primary transfer device 15 (Y, M, C, K) for transferring each toner image to an intermediate transfer device 20, and a drum cleaning device 16 (Y, M, C, K) for removing and cleaning attachments such as toner remaining on the image holding surface of the photosensitive drum 11 after the primary transfer.

[0054] The photosensitive drum 11 is formed by forming an image holding surface having a photoconductive layer (photosensitive layer) made of a photosensitive material on the circumference of a grounded cylindrical or columnar substrate. The photosensitive drum 11 is supported to rotate in the direction indicated by arrow A by receiving power transmitted from a rotation drive device (not shown).

[0055] like Figure 2 As shown in FIG. 1 , the charging device 12 is composed of a contact type charging roller 121 arranged in a state of contact with the photosensitive drum 11. A cleaning roller 122 for cleaning the surface of the charging roller 121 is arranged on the back of the charging roller 121. A charging voltage is supplied to the charging roller 121 of the charging device 12. As the charging voltage, a voltage or current having the same polarity as the charging polarity of the toner supplied from the developing device 14 is supplied when the developing device 14 performs reverse development. In addition, as the charging device 12, a non-contact type charging device such as a scorotron arranged on the surface of the photosensitive drum 11 in a non-contact state can be used.

[0056] The exposure device 13 irradiates the peripheral surface of the charged photosensitive drum 11 with light according to image information input to the image forming apparatus 1 to form an electrostatic latent image. The image information (signal) input to the image forming apparatus 1 by any mechanism when forming a latent image is transmitted to the exposure device 13.

[0057] The exposure device 13 is composed of an LED print head, which forms an electrostatic latent image by irradiating light corresponding to image information to the photosensitive drum 11 using a plurality of LEDs (Light Emitting Diodes) arranged in the axial direction of the photosensitive drum 11. Alternatively, an exposure device that deflects and scans a laser beam formed according to the image information in the axial direction of the photosensitive drum 11 may be used as the exposure device 13.

[0058] The developing devices 14 (Y, M, C, K) are each configured by arranging a developing roller 141 that holds the developer and conveys it to a developing area that faces the photosensitive drum 11, a stirring and supplying member 142 that is composed of a screw conveyor or the like and supplies the developer while stirring it through the developing roller 141, a stirring and conveying member 143 that is composed of a screw conveyor or the like and conveys the developer to the stirring and supplying member 142 while stirring it, and a layer thickness limiting member 144 that limits the amount (layer thickness) of the developer held by the developing roller 141, etc., inside a frame 140 that is formed with an opening at a position that faces the photosensitive drum 11 and a developer storage chamber. As the developer of four colors, for example, a two-component developer containing a non-magnetic toner and a magnetic carrier is used.

[0059] The primary transfer device 15 (Y, M, C, K) is a contact type transfer device having a primary transfer roller, which rotates while 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 direct current voltage having a polarity opposite to the charging polarity of the toner is supplied from a power supply device (not shown).

[0060] like Figure 2 As shown in the figure, the drum cleaning device 16 is composed of a container-shaped body 160 with a part of the body opened, a cleaning plate 161 configured to contact the peripheral surface of the photosensitive drum 11 after the primary transfer with a required pressure to remove and clean the residual toner and other attached materials, and a delivery member 162 such as an auger that recovers the toner and other attached materials removed by the cleaning plate 161 and delivers them to a recovery system not shown. As the cleaning plate 161, a plate-shaped member (e.g., a scraper) made of a material such as rubber is used.

[0061] like Figure 1As shown, the intermediate transfer device 20 is arranged at a position above each image generating device 10 (Y, M, C, K). The intermediate transfer device 20 mainly includes an intermediate transfer belt 21 that rotates in the direction indicated by arrow B while passing through the primary transfer position between the photosensitive drum 11 and the primary transfer device 15 (primary transfer roller), a plurality of belt support rollers 22 to 25 that rotatably support the intermediate transfer belt 21 while holding it in a desired state from its inner surface, a secondary transfer device 30 that is arranged on the outer peripheral surface (image holding surface) side of the intermediate transfer belt 21 supported by the belt support roller 25 and transfers the toner image on the intermediate transfer belt 21 to the recording paper 5 for secondary transfer, and a belt cleaning device 26 that removes and cleans the toner, paper dust and other attached materials that remain on the outer peripheral surface of the intermediate transfer belt 21 after passing through the secondary transfer device 30.

[0062] As the intermediate transfer belt 21, for example, an endless belt made of a material obtained by dispersing a resistance adjusting agent such as carbon black in a synthetic resin such as a polyimide resin or a polyamide resin is used. The belt support roller 22 is a driving roller that is rotationally driven by a driving device not shown, the belt support roller 23 is a surface-exposed roller (face-out roll) that maintains the moving position of the intermediate transfer belt 21, the belt support roller 24 is a tension-applying roller that applies tension to the intermediate transfer belt 21, and the belt support roller 25 is a support roller for secondary transfer.

[0063] like Figure 1 As shown, the secondary transfer device 30 is a contact type transfer device including a secondary transfer roller 31, which rotates in contact with the peripheral surface of the intermediate transfer belt 21 at a secondary transfer position which is an outer peripheral surface portion of the intermediate transfer belt 21 supported by the belt support roller 25 in the intermediate transfer device 20, and is supplied with a secondary transfer voltage. A direct current voltage showing a polarity opposite to or the same polarity as the charging polarity of the toner is supplied to the secondary transfer roller 31 or the belt support roller 25 of the intermediate transfer device 20 as the secondary transfer voltage.

[0064] like Figure 2 As shown in the figure, the belt cleaning device 26 is composed of a container-shaped main body 260 with a part of the belt opening, a cleaning plate 261 arranged to contact the peripheral surface of the intermediate transfer belt 21 after the secondary transfer with a required pressure to remove and clean the residual toner and other attached materials, and a delivery member 262 such as an auger that recovers the toner and other attached materials removed by the cleaning plate 261 and delivers them to a recovery system (not shown). As the cleaning plate 261, a plate-shaped member (e.g., a scraper) made of a material such as rubber is used.

[0065] The fixing device 40 is configured by arranging a drum-shaped or belt-shaped heating rotating body 41 heated by a heating mechanism so that the surface temperature is maintained at a desired temperature, and a drum-shaped or belt-shaped pressing rotating body 42 that rotates with a predetermined pressure in contact with the heating rotating body 41 in a state substantially along the axial direction of the heating rotating body 41. An exit roller 43 for conveying the recording paper 5 subjected to the fixing process is provided at the exit portion of the fixing device 40. In the fixing device 40, the contact portion where the heating rotating body 41 and the pressing rotating body 42 come into contact becomes a fixing process portion where the desired fixing process (heating and pressing) is performed.

[0066] The paper feed device 50 is disposed at a position below the image generating devices 10 (Y, M, C, K) of yellow (Y), magenta (M), cyan (C), and black (K). The paper feed device 50 is mainly composed of a plurality of (or a single) paper containers 51 that contain recording paper 5 of a desired size, type, etc., and feeding devices 52 and 53 that feed the recording paper 5 one by one from the paper container 51. The paper container 51 is installed, for example, to be pulled out toward the front side (the side facing when operated by the user) of the device body 1a, and toward the front side of the paper surface in the illustrated example.

[0067] Examples of the recording paper 5 include plain paper, thin paper, and OHP sheets used in electrophotographic copiers and printers. In order to further improve the smoothness of the image surface after fixing, it is preferred that the surface of the recording paper 5 is as smooth as possible. For example, coated paper obtained by coating the surface of plain paper with a resin or the like, and so-called thick paper with a relatively large basis weight such as coated paper for printing can be used.

[0068] A paper feeding and conveying path 56 is provided between the paper feeding device 50 and the secondary transfer device 30. The paper conveying roller pair 54, 55 or a conveying guide device (not shown) for conveying the recording paper 5 fed from the paper feeding device 50 to the secondary transfer position. The paper conveying roller pair 55 is configured as, for example, a registration roller for adjusting the conveying timing of the recording paper 5. In addition, a paper discharge conveying section 58 having first to fourth paper discharge conveying paths 57a to 57d is provided at the upper portion of the fixing device 40 along the vertical direction Z. The first to fourth paper discharge conveying paths 57a to 57d are used to discharge the fixed recording paper 5 fed from the outlet roller 43 of the fixing device 40 to a sheet discharge device 60 as an example of a sheet discharge mechanism provided at the upper portion of the device body 1a.

[0069] The sheet discharge device 60 includes a first discharge tray 61 and a second discharge tray 62 of a so-called cylindrical discharge type provided at the upper portion of the device body 1a, and a third discharge tray 63 provided on the side (left side in the figure) of the paper discharge conveying section 58 so as to face outward. Inside the paper discharge conveying section 58, a first paper discharge conveying path 57a branching from the second paper discharge conveying path 57b and provided with a first paper discharge roller pair 64 for discharging the recording paper 5 onto the first discharge tray 61, a third paper discharge conveying path 57c branching from the second paper discharge conveying path 57b and provided with a second paper discharge roller pair 66 for discharging the recording paper 5 onto the second discharge tray 62, and a fourth paper discharge conveying path 57d branching from the third paper discharge conveying path 57c and provided with a third paper discharge roller pair 67 for discharging the recording paper 5 onto the third discharge tray 63 are provided.

[0070] In addition, Figure 1 In the figure, reference numeral 68 indicates a pair of paper conveying rollers provided in the middle of the second paper discharge conveying path 57b, G1 indicates a first switching gate branching between the first paper discharge conveying path 57a and the second paper discharge conveying path 57b, and G2 indicates a second switching gate branching between the third paper discharge conveying path 57c and the fourth paper discharge conveying path 57d. The sheet discharge device 60 will be described in detail later.

[0071] And, if Figure 2 As shown, a double-sided transport path 70 having a paper transport roller pair 69 is provided inside the device body 1a. While the recording paper 5 having an image formed on one side is held by the first paper discharge roller pair 64, the paper transport roller pair 69 switches the rotation direction of the first paper discharge roller pair 64 from the forward direction to the reverse direction, thereby reversing the front and back sides of the recording paper 5 and transporting it to the paper transport roller pair 55 again.

[0072] exist Figure 1 In the figure, symbol 71 indicates a manual tray which is freely opened and closed and is provided on the side (the left side in the figure) of the device body 1a of the image forming device 1, and between the manual tray 71 and the paper conveying roller pair 55, there are provided a feeding device 72 for feeding out the recording paper 5 contained in the manual tray 71 one by one, and a manual paper feeding and conveying path 74 which is composed of a paper conveying roller pair 73 and a conveying guide device not shown.

[0073] And, in Figure 1 In the figure, reference numeral 145 (Y, M, C, K) respectively denotes a plurality of toner boxes arranged in a direction perpendicular to the paper surface and containing developers containing at least toner to be supplied to the corresponding developing devices 14 (Y, M, C, K).

[0074] And, in Figure 1 In the figure, reference numeral 100 denotes a control device that centrally controls the operation of the image forming apparatus 1. The control device 100 includes a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), or a bus or communication interface that connects the CPU and ROM, etc. (not shown).

[0075] <Operation of Image Forming Apparatus>

[0076] Hereinafter, a basic image forming operation by the image forming apparatus 1 will be described.

[0077] Here, an operation of forming a full-color image composed of a combination of toner images of four colors (Y, M, C, K) using the four image generating devices 10 (Y, M, C, K) will be described.

[0078] When the control device 100 receives command information requesting an image forming operation (printing), the image forming apparatus 1 activates the four image generating devices 10 (Y, M, C, K), the intermediate transfer device 20, the secondary transfer device 30, the fixing device 40, and the like.

[0079] Then, in each image forming device 10 (Y, M, C, K), first, each photosensitive drum 11 rotates in the direction indicated by arrow A, and each charging device 12 charges the surface of each photosensitive drum 11 to a desired polarity (negative polarity in Embodiment 1) and potential. Next, the exposure device 13 irradiates light onto the surface of the charged photosensitive drum 11, and forms an electrostatic latent image of each color component composed of a desired potential difference on the surface. The light is emitted based on an image signal obtained by converting the image information input to the image forming device 1 into each color component (Y, M, C, K).

[0080] Next, each image generating device 10 (Y, M, C, K) supplies the toner of the corresponding color (Y, M, C, K) charged to the required polarity (negative polarity) from the developing roller 141 to the electrostatic latent image of each color component formed on the photosensitive drum 11 to electrostatically adhere and develop it. Through this development, the electrostatic latent image of each color component formed on each photosensitive drum 11 is visualized as a toner image of four colors (Y, M, C, K) developed by the toner of the corresponding color.

[0081] Next, if the toner images of each color formed on the photosensitive drum 11 of each image generating device 10 (Y, M, C, K) are transmitted to the primary transfer position, the primary transfer device 15 (Y, M, C, K) transfers the toner images of each color once in a state of sequentially overlapping with the intermediate transfer belt 21 of the intermediate transfer device 20 rotating in the direction indicated by the arrow B.

[0082] In each image generating device 10 (Y, M, C, K) where primary transfer has been completed, the drum cleaning device 16 scrapes away the attached matter to clean the surface of the photosensitive drum 11. Thus, each image generating device 10 (Y, M, C, K) is ready to perform the next image generating operation.

[0083] Next, in the intermediate transfer device 20, the toner image primarily transferred by the rotation of the intermediate transfer belt 21 is held and transported to the secondary transfer position. On the other hand, in the paper feeding device 50, the required recording paper 5 is fed to the paper feeding transport path 56 in coordination with the image generation operation. On the paper feeding transport path 56, the paper feeding roller pair 55 as the registration roller feeds the recording paper 5 in coordination with the transfer timing and supplies it to the secondary transfer position.

[0084] At the secondary transfer position, the secondary transfer roller 31 of the secondary transfer device 30 secondary transfers the toner image on the intermediate transfer belt 21 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 toner and other attached materials remaining on the surface of the intermediate transfer belt 21 after the secondary transfer.

[0085] Next, the recording paper 5 to which the toner image is secondarily transferred is peeled off from the intermediate transfer belt 21 and the secondary transfer roller 31 and then conveyed to the fixing device 40. In the fixing device 40, the recording paper 5 after the secondary transfer is introduced into the contact portion between the rotating heating rotating body 41 and the pressing rotating body 42 and passed through, thereby performing a necessary fixing process (heating and pressing) to fix the unfixed toner image on the recording paper 5. Finally, when the image forming operation of forming an image only on one side of the recording paper 5 after the fixing is completed, the recording paper 5 is discharged to any one of the first to third discharge trays 61 to 63 provided on the upper part of the device body 1a via the first to fourth paper discharge conveying paths.

[0086] 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 roller pair 64, but the rotation direction of the first paper discharge roller pair 64 is switched to the reverse direction while the rear end of the recording paper 5 is held by the first paper discharge roller pair 64. The recording paper 5 transported in the reverse direction by the first paper discharge roller pair 64 is transported to the double-sided transport path 70 including the paper transport roller pair 69 and the like, and is transported again to the paper transport roller pair 55 in a state where the front and back sides are reversed. The paper transport roller pair 55 feeds the recording paper 5 to the 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 any one of the first to fourth paper discharge transport paths 57a to 57d to any one of the first to third discharge trays 61 to 63 provided on the upper part of the apparatus main body 1a.

[0087] Through the above operation, the recording paper 5 having a full-color image formed by combining toner images of four colors formed on one side or both sides thereof is output.

[0088] <Structure of sheet discharge device>

[0089] like Figure 2 As shown, the image forming apparatus 1 includes a sheet discharge device 60 on an upper portion of an apparatus body 1 a , and the sheet discharge device 60 discharges recording paper 5 as an example of a sheet having an image formed on one side or both sides thereof.

[0090] The sheet discharge device 60 according to the first embodiment is configured as a so-called in-tube discharge type sheet discharge device that discharges the recording paper 5 into a tube as an upper portion of the apparatus body 1 a of the image forming apparatus 1 .

[0091] like Figure 2 and Figure 3 As shown, the sheet discharge device 60 includes the first to third discharge trays 61 to 63 for accommodating the recording paper 5 on which the image is fixed by the fixing device 40 and discharged so that the end portion on the upstream side along the discharge direction thereof abuts against the wall surface, and the first to third paper discharge roller pairs 64, 66, 67 for discharging the recording paper 5 on which the image is fixed by the fixing device 40 to the first to third discharge trays 61 to 63.

[0092] Here, as the sheet discharge device 60 , in particular, the first discharge tray 61 including the first paper discharge roller pair 64 will be described.

[0093] As described above, the first discharge tray 61 is configured as a so-called in-cylinder discharge type discharge tray that discharges the recording paper 5 into the cylinder of the apparatus main body 1a of the image forming apparatus 1. Figure 2 and Figure 3As shown, the first discharge tray 61 includes: an inclined portion 611 as an example of an inclined surface, which is inclined in such a manner that the end portion on the upstream side along the discharge direction thereof is located inside the device body 1a; a flat portion 612, which is arranged on the downstream side of the inclined portion 611 along the discharge direction and is formed flatly along the horizontal direction X; and a wall surface 613, which is arranged at the end portion on the upstream side of the inclined portion 611 along the discharge direction, is composed of a surface which is slightly inclined in such a manner that the lower end portion along the vertical direction Z is located on the downstream side along the discharge direction, and is aligned with the end portion on the upstream side along the discharge direction of the recording paper 5 discharged onto the first discharge tray 61.

[0094] Both ends of the inclined portion 611 of the first discharge tray 61 along the width direction (depth direction) Y intersecting the discharge direction of the recording paper 5 are closed by the front and rear side surfaces 1b and 1c constituting the apparatus body 1a. Figure 2 In the figure, reference numeral 1d denotes an air outlet opened on a side surface 1c of the device body 1a.

[0095] like Figure 2 and Figure 3 As shown, at the end portion of the upstream side of the first discharge tray 61 along the discharge direction of the recording paper 5, a first paper discharge roller pair 64 for discharging the recording paper 5 obliquely upward onto the first discharge tray 61 is provided at approximately the same height as the flat portion 612 of the first discharge tray 61.

[0096] In addition, in the sheet discharging device 60 configured as described above, Figure 4 (a) Figure 4 As shown in (b), when the recording paper 5 is discharged to the first discharge tray 61 by the first paper discharge roller pair 64, the two sides of the inclined portion 611 of the first discharge tray 61 along the width direction intersecting the discharge direction are closed by the side surfaces 1b and 1c of the device body 1a, so that as the recording paper 5 is discharged (moved), the air below the recording paper 5 forms a vortex-shaped air accumulation portion 75. In addition, Figure 4 The figure schematically shows an image obtained by photographing the state in which the front cover (not shown) of the image forming apparatus 1 is opened so as to observe the posture of the recording paper 5 discharged onto the first discharge tray 61 .

[0097] Therefore, the recording paper 5 discharged to the first discharge tray 61 does not immediately fall onto the first discharge tray 61 due to the presence of the air reservoir 75, but temporarily floats in the air. Then, the air constituting the air reservoir 75 existing below the recording paper 5 on the first discharge tray 61 moves toward the periphery of the first discharge tray 61, and the recording paper 5 falls onto the surface of the inclined portion 611 of the first discharge tray 61 or the like under the action of its own weight.

[0098] As a result, there is a technical problem as follows: In the sheet discharge device 60 configured as described above, Figure 4 As shown in (b), when the recording paper 5 is discharged onto the first discharge tray 61, due to the influence of the air accumulation portion 75 below the recording paper 5, the posture of the recording paper 5 becomes unstable and disordered, resulting in a state of so-called bank remaining, in which the end of the recording paper 5 on the upstream side along the discharge direction contacts the wall 613 of the first discharge tray 61 midway and remains in a bent state.

[0099] Therefore, the sheet discharge device involved in this embodiment 1 is constructed as follows: it has multiple exhaust passages arranged on the wall surface of the discharge tray and inclined in a manner that expands toward the outside of both end portions along the width direction intersecting the sheet discharge direction as they tend to the bottom of the wall surface, so as to suppress the disorder of the posture of the sheets discharged onto the discharge tray when the sheets are discharged.

[0100] Furthermore, the sheet discharge device according to the first embodiment is configured such that a plurality of exhaust passages are provided in a symmetrical shape with a reference position as a center, and the reference position is, for example, the center in a direction intersecting the sheet discharge direction.

[0101] That is, in the sheet discharge device 60 according to the first embodiment, Figure 5 As shown, a plurality of exhaust passages 80, 80, ... are provided on the wall surface 613 of the first discharge tray 61. Figure 6 and Figure 7 As shown, a plurality of ribs 81, 81, ... are integrally formed on the wall surface 613 of the first discharge tray 61 so as to protrude from the inner side surface of the wall surface 613 toward the inside of the first discharge tray 61 as linear protrusions for forming a plurality of exhaust passages 80, 80, ...

[0102] like Figure 6 As shown, the plurality of ribs 81 , 81 , . . . are provided in a bilaterally symmetrical shape with the reference position C as the center. The reference position after the ribs 81 , 81 . . . are provided is configured as, for example, the center in the width direction intersecting the discharge direction of the recording paper 5 .

[0103] If further explanation is given, Figure 6 and Figure 7 As shown, a plurality of ribs are arranged parallel to each other on the wall 613 of the first discharge tray 61 in a state where they are inclined at an angle θ relative to the vertical direction Z in such a manner that they expand outwardly at both end portions along the width direction intersecting the discharge direction of the recording paper 5 as they approach the bottom of the wall 613, so that they have a left-right symmetrical shape with the center of the width direction intersecting the discharge direction of the recording paper 5, i.e., a reference position C.

[0104] The plurality of ribs 81, 81, ... are formed into elongated convex shapes having a desired width and height with respect to the wall surface 613 of the first discharge tray 61. Then, between the adjacent ribs 81, 81, ... among the plurality of ribs 81, 81, ..., a plurality of exhaust passages 80, 80, ... are provided as spaces partitioned between the adjacent ribs 81, 81, ....

[0105] Similar to the multiple ribs 81 , 81 . . . , the multiple exhaust passages 80 , 80 . . . are arranged in an inclined state so as to expand outwardly toward both ends along the width direction intersecting the discharge direction of the recording paper 5 as they go downward along the vertical direction Z of the wall surface 613 .

[0106] In the plurality of exhaust passages 80, 80 ..., the higher the height of the plurality of ribs 81, 81 ... and the larger the intervals between the plurality of ribs 81, 81 ..., the larger the cross-sectional area of ​​each exhaust passage 80, 80 ... is set. Conversely, in the plurality of exhaust passages 80, 80 ..., the lower the height of the plurality of ribs 81, 81 ... and the smaller the intervals between the plurality of ribs 81, 81 ..., the smaller the cross-sectional area of ​​each exhaust passage 80, 80 ... is set.

[0107] However, the combined cross-sectional area of ​​the plurality of 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 the exhaust passages 80, 80, ... .

[0108] In the above structure, in the sheet discharge device involved in this embodiment 1, as described below, compared with a case where there are no multiple exhaust passages arranged on the wall surface of the discharge tray and inclined in a manner that expands toward the outer sides of both end portions in the width direction intersecting the sheet discharge direction as they tend to the bottom of the wall surface, it is possible to suppress the posture disorder of the sheets discharged onto the discharge tray when discharging the sheets.

[0109] That is, in the sheet discharge device 60 according to the first embodiment, Figure 1 As shown, the recording paper 5 having an image formed on one side or both sides thereof is discharged onto any one of the first to third discharge trays 61 to 63 .

[0110] At this time, in the sheet discharging device 60, as shown in FIG. Figure 4 As shown in (a), when the recording paper 5 with an image formed on one side or both sides is discharged onto the first discharge tray 61, the recording paper 5 with an image formed on one side or both sides is discharged by the first paper discharge roller pair 64 in a manner substantially parallel to the flat portion 612 of the first discharge tray 61.

[0111] At this time, due to various reasons 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 sometimes produces a downward curl in a convex shape toward the first discharge tray 61 side or an upward curl in a concave shape toward the first discharge tray 61 side.

[0112] In the sheet discharge device 60 , immediately after the recording paper 5 is discharged onto the first discharge tray 61 , an air reservoir 75 where air accumulates exists below the recording paper 5 .

[0113] In addition, in the sheet discharge device 60 according to the first embodiment, Figure 5 As shown, a plurality of exhaust passages 80, 80, ... are provided on a wall surface 613 which is an end portion of the first discharge tray 61 on the upstream side along the discharge direction of the recording paper 5. The plurality of exhaust passages 80, 80, ... are inclined so as to expand outwardly toward both ends in the width direction intersecting the discharge direction of the recording paper 5 as they approach the lower side of the wall surface 613 of the first discharge tray 61.

[0114] Therefore, when the recording paper 5 is discharged onto the first discharge tray 61, Figure 8 As shown, the air constituting the air accumulation portion 75 existing below the recording paper 5 can quickly escape toward the top of the first discharge tray 61 via a plurality of exhaust passages 80, 80, etc. provided at the upstream end of the first discharge tray 61 along the discharge direction of the recording paper 5.

[0115] At this time, the plurality of exhaust passages 80, 80, ... are provided in an inclined state so as to expand toward the outer sides of both ends in the width direction intersecting the discharge direction of the recording paper 5 as they go toward the lower side of 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 as to expand toward the outer sides of both ends in the width direction intersecting the discharge direction along the inclination of the plurality of ribs 81, 81, ... so that the ends on the upstream side along the discharge direction come into contact with the surfaces of the plurality of ribs 81, 81, ...

[0116] As a result, even if the recording paper 5 discharged onto the first discharge tray 61 has a downward curl or an upward curl, the recording paper 5 contacts the plurality of ribs 81, 81, . . . to expand toward both ends along the width direction thereof, and is thus discharged in a state in which the curvature is corrected.

[0117] In this way, in the sheet discharge device 60 involved in the present embodiment 1, compared with the case where there is no plurality of exhaust passages 80, 80... which are arranged on the wall 613 of the first discharge tray 61 and are inclined in a manner that expands toward the outer sides of the two end portions in the width direction intersecting the discharge direction of the recording paper 5 as they tend to the bottom of the wall 613, it is possible to suppress the posture disorder of the recording paper 5 discharged onto the first discharge tray 61 when discharging the recording paper 5.

[0118] Implementation Method 2

[0119] Fig. 9 1 is a perspective view showing the structure of an image forming apparatus to which a sheet discharge apparatus according to Embodiment 2 of the present invention is applied. Components corresponding to those in Embodiment 1 are denoted by the same reference numerals and described below.

[0120] That is, Figures 9 to 11 As shown, the sheet discharge device 60 involved in embodiment 2 is constructed as follows: the multiple exhaust passages 80, 80... are not formed by a convex portion arranged on the wall 613 of the first discharge tray 61, but are formed by a slit portion directly opening on the wall 613 of the first discharge tray 61 in a shape corresponding to the multiple exhaust passages 80, 80...

[0121] A plurality of exhaust passages 80, 80... are provided on the wall surface 613 of the first discharge tray 61, and the plurality of exhaust passages 80, 80... are composed of slit portions inclined in a manner that expands toward the outer sides of both end portions along the width direction intersecting the discharge direction of the recording paper 5 as they tend to be downward in the vertical direction Z of the wall surface 613.

[0122] For example, when molding the member constituting the wall surface 613 of the first discharge tray 61 , the plurality of exhaust passages 80 , 80 . . . are formed by integral molding.

[0123] The area of ​​the wall 613 of the first discharge tray 61 between the multiple exhaust passages 80, 80... can be composed of the same plane as the surface of the wall 613, but in order to reduce the contact resistance with the recording paper 5, it is preferably set to a rib shape protruding from the surface of the wall 613 in the same way as in embodiment 1.

[0124] 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 accumulation portion 75 existing below the recording paper 5 escapes into the inside of the device body 1a through the plurality of exhaust passages 80, 80, ... Therefore, unlike the first embodiment, the air flowing through the plurality of exhaust passages 80, 80, ... does not flow from the lower side to the upper side along the vertical direction Z along the length direction of the plurality of exhaust passages 80, 80, ..., but flows from the surface of the wall surface 613 of the first discharge tray 61 to the back side (inner side) through the plurality of exhaust passages 80, 80, ..., so that the air constituting the air accumulation portion 75 existing below the recording paper 5 can escape more quickly.

[0125] The other structures and functions are the same as those in the first embodiment, so the description thereof will be omitted.

[0126] In addition, in the above-described embodiment, a full-color image forming device is described, but the sheet discharge device involved in the present invention is not limited thereto and can of course be similarly applied to a monochrome image forming device. In addition to the image forming device, it can of course be similarly applied to a trimmer that performs binding or punching operations on sheets, etc.

[0127] (Note) (1)

[0129] A sheet discharging device comprising:

[0130] a discharge tray for accommodating discharged sheets in such a manner that an end portion on the upstream side along the discharge direction thereof abuts against a wall surface; and

[0131] A plurality of exhaust passages are provided on a wall surface of the discharge tray and are inclined so as to expand toward outer sides of both ends along a width direction intersecting with a discharge direction of the sheets as they go downwardly toward the wall surface. (2)

[0133] The sheet discharging device according to (1), wherein:

[0134] The plurality of exhaust passages are provided in a symmetrical shape with a reference position as a center. (3)

[0136] The sheet discharging device according to (2), wherein:

[0137] The reference position is the center of a direction intersecting with a discharge direction of the sheet. (4)

[0139] The sheet discharging device according to (2), wherein:

[0140] The plurality of exhaust passages are formed by protrusions or slits provided on a wall surface of the discharge tray. (5)

[0142] The sheet discharging device according to (1), wherein:

[0143] The discharge tray has an inclined surface whose end portion on the upstream side along the discharge direction of the sheet is formed lowest. (6)

[0145] The sheet discharge device according to any one of (1) to (5), wherein:

[0146] The sheet is discharged along the inclined surface of the discharge tray under its own weight in a state where an end portion on the upstream side along the discharge direction of the sheet abuts against the wall surface. (7)

[0148] An image forming device comprising:

[0149] An image forming mechanism that forms an image on a sheet; and

[0150] a sheet discharging mechanism for discharging the sheet on which the image is formed by the image forming mechanism,

[0151] As the sheet discharging mechanism, the sheet discharging device described in any one of (1) to (6) is used.

[0152] According to the sheet discharge device involved in (1), compared with a case where there are no multiple exhaust passages arranged on the wall surface of the discharge tray and inclined in a manner that expands toward the outside of both end portions in the width direction intersecting the sheet discharge direction as they tend to the bottom of the wall surface, it is possible to suppress the posture disorder of the sheets discharged onto the discharge tray when the sheets are discharged.

[0153] According to the sheet discharge device according to (2), compared with a case where a plurality of exhaust passages are provided in an asymmetrical shape, it is possible to effectively suppress the posture disorder of the sheet.

[0154] According to the sheet discharge device of (3), it is easier to restrict the sheet symmetrically in the width direction than when the reference position is located at a position other than the center in the direction intersecting the sheet discharge direction.

[0155] According to the sheet discharge device according to (4), the plurality of exhaust passages can be easily formed compared to a case where the plurality of exhaust passages are formed by other than the convex portion or the slit portion provided on the wall surface of the discharge tray.

[0156] According to the sheet discharge device of (5), compared with a case where the discharge tray does not have a sloped surface formed lowest at the upstream end portion along the sheet discharge direction, the sheets can be reliably aligned by contacting the wall surface.

[0157] According to the sheet discharge device according to (6), the structure can be simplified compared to a case where the sheet comes into contact with the wall surface of the discharge tray due to a force other than its own weight.

[0158] According to the image forming apparatus of (7), compared with a case where the sheet discharge device described in any one of (1) to (6) is not used as the sheet discharge mechanism, it is possible to suppress the posture of the sheet discharged onto the discharge tray from being disturbed when the sheet is discharged.

[0159] The above-mentioned embodiments of the present invention are provided for the purpose of illustration and description. In addition, the embodiments of the present invention do not fully and exhaustively include the present invention, and do not limit the present invention to the disclosed methods. Obviously, various modifications and changes are self-evident to those skilled in the art to which the present invention belongs. The present embodiment is selected and described in order to most easily understand the principles of the present invention and its application. Thus, other technicians in the art can understand the present invention through various variations optimized for specific uses assumed to be various embodiments. The scope of the present invention is defined by the above claims and their equivalents.

Claims

1. A sheet discharging device comprising: a discharge tray for accommodating discharged sheets in such a manner that an end portion on the upstream side along the discharge direction thereof abuts against a wall surface; and A plurality of exhaust passages are provided on a wall surface of the discharge tray and are inclined so as to expand toward outer sides of both ends along a width direction intersecting with a discharge direction of the sheets as they go downwardly toward the wall surface.

2. The sheet discharge device according to claim 1, wherein: The plurality of exhaust passages are provided in a symmetrical shape with a reference position as a center.

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

4. The sheet discharging device according to claim 2, wherein: The plurality of exhaust passages are formed by protrusions or slits provided on a wall surface of the discharge tray.

5. The sheet discharging device according to claim 1, wherein: The discharge tray has an inclined surface whose end portion on the upstream side along the discharge direction of the sheet is formed lowest.

6. The sheet discharge device according to any one of claims 1 to 5, wherein: The sheet is discharged along the inclined surface of the discharge tray under its own weight in a state where an end portion on the upstream side along the discharge direction of the sheet abuts against the wall surface.

7. An image forming apparatus comprising: An image forming mechanism that forms an image on a sheet; and a sheet discharging mechanism for discharging the sheet on which the image is formed by the image forming mechanism, As the sheet discharging mechanism, the sheet discharging device according to any one of claims 1 to 6 is used.

Images