Sheet ejection device and image forming apparatus

Abstract

To improve the integrity of the discharged sheets. [Solution] A sheet discharge device comprising: a housing having a discharge opening and an upper surface, the upper surface including an inclined first surface and a second surface provided downstream of the first surface; a first extension tray movable between a first retracted position and a first use position; a second extension tray rotatable between a second retracted position and a second use position, having a fourth surface and an interlocking part configured to move the first extension tray from the first retracted position to the first use position when it rotates from the second retracted position to the second use position; and a discharge roller, wherein at least a portion of the third surface moves upward when the first extension tray moves from the first retracted position to the first use position.

Description

Technical Field

[0001] The present invention relates to a sheet discharging device for discharging sheets and an image forming device for forming an image on a sheet.

Background Art

[0002] Patent Document 1 describes an image forming apparatus including a paper discharge tray formed on the upper surface of a printer main body, and an extension tray disposed on the downstream side of the paper discharge tray and supporting a sheet together with the paper discharge tray in a raised state.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the configuration of the above document, the sheet discharged toward the paper discharge tray and the extension tray may not be able to slide down along the inclination of the paper discharge tray, and the alignment of the sheet may be deteriorated.

[0005] An object of the present invention is to provide a sheet discharging device and an image forming device capable of improving the alignment of the discharged sheet.

Means for Solving the Problems

[0006] One aspect of the present invention is a housing having a discharge opening through which a sheet being discharged in the sheet discharge direction passes, and an upper surface, wherein the upper surface includes a first surface inclined upward toward the downstream direction of the sheet discharge, and a second surface provided downstream of the first surface in the sheet discharge direction, the first surface and the second surface configured to receive the sheet being discharged from the discharge opening, and the angle between the second surface and a horizontal surface being smaller than the angle between the first surface and the horizontal surface, a first extension tray disposed on the upper surface and movable between a first retracted position and a first use position, the first extension tray having a third surface, a second extension tray disposed on the upper surface and rotatable between a second retracted position and a second use position, the second extension tray having a fourth surface, and an interlocking part configured to move the first extension tray from the first retracted position to the first use position when it rotates from the second retracted position to the second use position, and a configuration for discharging the sheet from the discharge opening A discharge roller is provided which is capable of transporting the sheet to a position in contact with the third and fourth surfaces when the first extension tray is in the first use position and the second extension tray is in the second use position, wherein when the first extension tray is in the first use position, at least a portion of the third surface is located downstream of the first surface and above the second surface in the sheet discharge direction and is inclined upward toward the downstream direction of the sheet discharge, and when the second extension tray is in the second use position, at least a portion of the fourth surface is located downstream of the third surface and above the second and third surfaces in the sheet discharge direction and is inclined upward toward the downstream direction of the sheet discharge, and when the first extension tray moves from the first retracted position to the first use position, at least a portion of the third surface moves upward. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a sheet discharge device and an image forming apparatus that can improve the consistency of discharged sheets. [Brief explanation of the drawing]

[0008] [Figure 1] A cross-sectional view showing the image forming apparatus according to Example 1. [Figure 2] A perspective view (a) and a cross-sectional view (b) showing the stored state of the first extension tray and the second extension tray according to Example 1. [Figure 3] A perspective view (a) and a cross-sectional view (b) showing the unfolded state of the first extension tray and the second extension tray according to Example 1. [Figure 4] Diagrams (a, b) illustrating the second extension tray according to Example 1. [Figure 5] Diagrams (a, b) illustrating the first extension tray according to Example 1. [Figure 6] A perspective view (a) and a cross-sectional view (b) showing the storage state of the first extension tray and the second extension tray according to Example 2. [Figure 7] A perspective view (a) and a cross-sectional view (b) showing the unfolded state of the first extension tray and the second extension tray according to Example 2. [Figure 8] Diagrams (a-c) illustrating the first and second extension trays according to Example 2. [Modes for carrying out the invention]

[0009] The embodiments relating to this disclosure will be described below with reference to the drawings.

[0010] Example 1 Figure 1 is a cross-sectional view showing an image forming apparatus 1 according to one embodiment (Embodiment 1) of the present disclosure. The image forming apparatus 1 is an image forming apparatus that forms an image on a sheet S by an electrophotographic process according to image information sent from an external device such as a computer that is communicably connected to the image forming apparatus 1.

[0011] In this disclosure, "image forming apparatus" refers to any apparatus that has the function of forming an image on a sheet, which is a recording material (recording medium). The image forming apparatus may be a single-function printer, a copier, or a multifunction device. The image forming apparatus may be an apparatus that mainly forms color images, or an apparatus that mainly forms monochrome images. Furthermore, the image forming apparatus may be a system (image forming system) in which an image forming apparatus main body that forms an image on a recording material and auxiliary equipment used together with the image forming apparatus main body are connected. Examples of auxiliary equipment include a sheet processing device (finisher) that performs processing such as binding on the sheet on which the image has been formed, a transport device that transports the sheet from the image forming apparatus main body to another device, and a feeder (optional feeder) that feeds the sheet toward the image forming apparatus main body. As the recording material (recording medium) sheet S, a variety of sheet materials of different sizes and materials can be used, such as plain paper and cardboard, sheet materials with surface treatments such as coated paper, sheet materials with special shapes such as envelopes and index paper, plastic film, cloth, etc.

[0012] The image forming apparatus 1 has a main body 1B which includes an image forming unit 1A as an image forming means and a housing 1C which houses the image forming unit 1A. The image forming unit 1A includes a photosensitive drum 8, a charging roller 80, an exposure device 7, a developing unit 81, and a transfer roller 9. The main body 1B has a cassette 2, a feed roller 3, a transport roller pair 4, a registration roller pair 5, a fixing device 10, a discharge roller pair 11 (discharge roller), a discharge tray 12, a main body case (main body frame, main body casing) 18, and a front door 13.

[0013] In the following description and drawings, the vertical direction (direction of gravity) when the image forming apparatus 1 is installed on a horizontal plane is referred to as the Z-axis direction. The direction of the rotation axis of the photosensitive drum 8 provided in the image forming apparatus 1 is referred to as the X-axis direction. The direction that intersects both the X-axis direction and the Z-axis direction is referred to as the Y-axis direction. The X-axis direction, Y-axis direction, and Z-axis direction are preferably orthogonal to each other. In this embodiment, the X-axis direction is the direction of the rotation axis of the discharge roller pair 11. A horizontal plane is a plane parallel to the X-axis direction and the Y-axis direction. The X-axis direction can also be referred to as the width direction of the sheet S. In addition, the direction of the rotation axis of the rotating body that conveys the sheet S (for example, the feeding roller 3, the conveying roller pair 4, the registration roller pair 5, and the discharge roller pair 11 (discharge roller)) is parallel to the X-axis direction.

[0014] The main body case 18 includes a cover member that forms the external surface of the image forming apparatus 1 and a frame member such as sheet metal that forms the frame of the image forming apparatus 1. The main body case 18 and the front door 13 form the housing 1C of the image forming apparatus 1. The front door 13 is an opening / closing member that can move between a closed position that closes an opening OP provided in the main body case 18 and an open position that opens the opening OP. By opening the front door 13, the user can access the inside of the housing 1C through the opening OP and, for example, replace the process cartridge 6, which will be described later. At least a portion of the front door 13, together with the cover member of the main body case 18, forms the external surface of the image forming apparatus 1.

[0015] The main body case 18 includes a discharge opening 11A, an upper surface including the top surface 18A and the discharge tray 12, and wall surfaces 17 (loading wall, alignment wall) (see also Figure 2). The upper surface of the main body case 18, together with the top surface 15 of the front door 13, forms the upper surface of the housing 1C. In other words, the upper surface of the housing 1C in this embodiment includes the top surface 18A and the discharge tray 12 of the main body case 18, and the top surface 15 of the front door 13.

[0016] The top surface 18A of the main body case 18 is a surface that extends in a direction intersecting the Z-axis direction and faces upward. The top surface 18A may be planar and orthogonal to the Z-axis direction. The discharge tray 12 is a surface that extends downstream in the sheet discharge direction D from a position below the discharge opening 11A. The discharge tray 12 is an inclined surface (first surface) that slopes upward toward the downstream in the sheet discharge direction D. In the present embodiment, the downstream end of the discharge tray 12 in the sheet discharge direction D is adjacent to the top surface 15 of the front door 13 and an extension tray portion 14 described later (FIG. 2(a)).

[0017] The top surface 15 of the front door 13 is a surface that extends in a direction intersecting the Z-axis direction and faces upward. The top surface 15 of the front door 13 is a second surface provided downstream of the discharge tray 12 (first surface) in the sheet discharge direction D, and is an example of a second surface of the housing 1C where the angle formed by the second surface and the horizontal plane is smaller than the angle formed by the first surface and the horizontal plane. In other words, the angle formed by the top surface 15 of the front door 13 and the horizontal direction (the inclination angle of the top surface 15 with respect to the horizontal direction) is smaller than the angle formed by the discharge tray 12 and the horizontal direction (the inclination angle of the discharge tray 12 with respect to the horizontal direction). The discharge tray 12 (first surface) and the top surface 15 of the front door 13 (second surface) are configured to receive the sheet S discharged by the discharge roller pair 11.

[0018] In the X-axis direction, at least a part of the discharge tray 12 and at least a part of the discharge opening 11A are located at the same position. That is, in the X-axis direction, the position of the discharge opening 11A and the position of the discharge tray 12 at least partially overlap. Also, in the X-axis direction, at least a part of the top surface 15 and at least a part of the discharge opening 11A are located at the same position. That is, in the X-axis direction, the position of the discharge opening 11A and the position of the top surface 15 at least partially overlap.

[0019] The top surface 15 of the front door 13 may be a plane orthogonal to the Z-axis direction. Without being limited to this, a part or all of the top surface 15 of the front door 13 may be inclined upward or downward toward the downstream in the sheet discharge direction D.

[0020] [[ID=]5] In this embodiment, an example is described in which the discharge tray 12, as the first surface, is provided on the main body case 18, and the top surface 15, as the second surface, is provided on the front door 13 (opening / closing member). In this embodiment, an example is described in which the extension tray section 14 and the extension tray storage section 21 (recess), which will be described later, are provided on the front door 13 (opening / closing member). However, the second surface, the extension tray section 14, and the extension tray storage section 21 (recess) may be provided on the main body case 18. Also, the housing 1C may be configured without a front door 13 (opening / closing member). Furthermore, the discharge tray 12 may be formed by the main body case 18 and the front door 13. For example, the main body case 18 and the front door 13 may be divided in the middle of the discharge tray 12. Also, a part of the upper surface of the front door 13 may be provided with an inclined surface that is inclined with respect to the top surface 15, and the inclined surface of the front door 13 and the discharge tray 12 of the main body case 18 may be configured to receive the sheet S together. In this case, the inclined surface of the front door 13 and the discharge tray 12 of the main body case 18 may form a continuous inclined surface. Alternatively, the main body case 18 and the front door 13 may form the top surface 15.

[0021] The discharge opening 11A is an opening in the housing 1C through which the sheet S, which is discharged in the sheet discharge direction D, passes. The discharge roller pair 11 is configured to discharge the sheet S, which has an image formed on it by the image forming unit 1A, through the discharge opening 11A.

[0022] The wall surface 17 is located upstream of the discharge tray 12 (first surface) in the sheet discharge direction D and below the discharge opening 11A, and extends in the vertical direction. The discharge opening 11A is formed within the wall surface 17, or between the upper end of the wall surface 17 and the top surface 18A of the main body case 18.

[0023] Part or all of the image forming unit 1A may be a cartridge that can be attached to or removed from the apparatus body 1B. In this embodiment, the image forming apparatus 1 includes a process cartridge 6 that can be attached to or removed from the apparatus body 1B. The process cartridge 6 has a photosensitive drum 8, a charging roller 80, and a developing unit 81. The process cartridge 6 can be attached to or removed from the apparatus body 1B through an opening OP by opening the front door 13 of the apparatus body 1B.

[0024] The image forming apparatus 1 may have a drum cartridge and a developer cartridge that are detachable from the apparatus body 1B instead of the process cartridge 6, and the drum cartridge and the developer cartridge may be detachable from each other. In this case, the drum cartridge may have a photosensitive drum 8 and a charging roller 80, and the developer cartridge may have a developer unit 81.

[0025] The photosensitive drum 8 functions as an image carrier that holds a latent image and a developer image (toner image). The photosensitive drum 8 is a drum-type electrophotographic photoreceptor (hereinafter referred to as the photosensitive drum 8). The photosensitive drum 8 is formed by using a photosensitive material such as OPC (organic photoconductive material), amorphous selenium, or amorphous silicon to form a photosensitive layer on the outer circumference of a cylindrical substrate made of aluminum, nickel, or the like. The photosensitive drum 8 is rotatably supported by the main body 1B of the apparatus and is configured to be rotationally driven by a drive source located in the main body 1B. The charging roller 80 is an example of a charger that charges the surface of the photosensitive drum 8. The developing unit 81 includes a toner storage section (developing container) that contains toner as a developer, and a developing roller (developing agent carrier) that carries the toner and supplies it to the photosensitive drum 8.

[0026] The exposure apparatus 7 comprises a laser light source and an optical system that guides the laser light emitted from the laser light source to the photosensitive drum 8. In this embodiment, the exposure apparatus 7 is positioned above the process cartridge 6. The exposure apparatus 7 may also be an LED exposure apparatus equipped with a plurality of LED light sources arranged in the direction of the rotation axis (main scanning direction) of the photosensitive drum 8. The transfer roller 9 faces the photosensitive drum 8 and forms a transfer section (transfer nip) between it and the photosensitive drum 8.

[0027] Cassette 2 is a storage section in which sheets S are loaded and stored. The feeding roller 3 is an example of a feeding unit that feeds sheets S from cassette 2. The fixing device 10 is a thermal fixing unit (image heating device) and includes, for example, a heating roller, a pressure roller that forms a fixing nip together with the heating roller, and a heat source such as a halogen lamp that heats the heating roller. The discharge roller pair 11 is an example of a discharge unit that discharges sheets S from the inside to the outside of the housing 1C.

[0028] In this embodiment, the direction of movement of the sheet S at the contact point with the discharge roller pair 11 is defined as the sheet discharge direction D. That is, in this embodiment, the sheet discharge direction D is perpendicular to the line connecting the center of one roller of the discharge roller pair 11 and the center of the other roller of the discharge roller pair 11 when viewed in the X-axis direction. In this embodiment, the sheet discharge direction D is along the Y-axis direction. The sheet discharge direction D may be parallel to the Y-axis direction or may intersect with the Y-axis direction. However, the sheet discharge direction D is intersect with the Z-axis direction (vertical direction).

[0029] The discharge tray 12 is provided on the upper surface of the housing 1C. The discharge tray 12 supports the lower surface of the sheet S discharged by the discharge roller pair 11. At least a portion of the discharge tray 12 is inclined vertically upward toward the downstream direction of the sheet discharge direction D.

[0030] (Image formation process) The operation of the image forming apparatus 1 will now be described. When the image forming apparatus 1 receives an instruction to execute an image forming operation (print instruction) containing image information from an external device, for example, it executes an image forming operation, which is a series of operations in which an image is formed on the sheets S while transporting the sheets S one by one.

[0031] In the image forming operation, a toner image is created in the image forming unit 1A. Specifically, the photosensitive drum 8 is rotated by the driving force of the drive source. The surface of the photosensitive drum 8 is uniformly charged to a predetermined polarity and potential by the charging roller 80. The exposure device 7 irradiates the photosensitive drum 8 with light based on the image information to perform exposure and write an electrostatic latent image to the surface of the photosensitive drum 8. The developing unit 81 supplies charged toner to the photosensitive drum 8 and develops the electrostatic latent image into a toner image. This toner image is transported to the transfer unit by the rotation of the photosensitive drum 8.

[0032] Meanwhile, in parallel with the operation of the image forming unit 1A, the sheet S is transported from the cassette 2 to the transfer unit. Specifically, the feed roller 3 feeds the top sheet S from the sheet bundle stored in the cassette 2. The fed sheet S is transported to the registration roller pair 5 via the transport roller pair 4. The registration roller pair 5 transports the sheet S to the transfer unit in time with the arrival of the toner image on the photosensitive drum 8 to the transfer unit. Then, by applying a transfer voltage to the transfer roller 9, the toner image is transferred from the photosensitive drum 8 to the sheet S in the transfer unit.

[0033] The sheet S onto which the toner image has been transferred in the transfer unit is transported to the fuser unit 10. The fuser unit 10 holds the sheet S with a fuser nip and performs a fixing process by heating and pressurizing the toner image on the sheet S while transporting it. The fixing process results in an image fixed to the sheet S. The sheet S that has passed through the fuser unit 10 is discharged to the outside of the housing 1C by the discharge roller pair 11 and loaded onto the discharge tray 12.

[0034] The sheet S, once discharged onto the discharge tray 12, slides down along the slope of the discharge tray 12 towards the upstream side in the sheet discharge direction D. The sheet S then stops either by hitting the wall surface 17 (loading wall, alignment wall) of the housing 1C located at the upstream end of the discharge tray 12 in the sheet discharge direction D, or by receiving frictional force from the discharge tray 12 or other sheets S already loaded on it.

[0035] (Extension tray section) The extension tray section 14 provided in the image forming apparatus 1 will be explained using Figures 1 to 5(b). Figure 2(a) is a perspective view showing the image forming apparatus 1 when the extension tray section 14 is in the retracted state. Figure 2(b) is a cross-sectional view of the extension tray section 14 shown in Figure 2(a) cut by a virtual plane perpendicular to the X-axis direction. Figure 3(a) is a perspective view showing the image forming apparatus 1 when the extension tray section 14 is in the unfolded state. Figure 3(b) is a cross-sectional view of the extension tray section 14 shown in Figure 3(a) cut by a virtual plane perpendicular to the X-axis direction.

[0036] As shown in Figures 1 and 3(a), the extension tray section 14 includes a first extension tray 40 and a second extension tray 30. In the X-axis direction, at least a portion of the extension tray section 14 and at least a portion of the discharge opening 11A are located at the same position. In other words, in the X-axis direction, the position of the discharge opening 11A and the position of the extension tray section 14 (the positions of the first extension tray 40 and the second extension tray 30) overlap at least partially.

[0037] The first extension tray 40 and the second extension tray 30 are positioned on the upper surface of the housing 1C (in this embodiment, the upper surface of the front door 13). The first extension tray 40 is movable (rotatable) between a first retracted position (first storage position, first closed position) shown in Figures 2(a) and 2(b) and a first usage position (first unfolded position, first open position) shown in Figures 3(a) and 3(b). The second extension tray 30 is rotatable between a second retracted position (first storage position, first closed position) shown in Figures 2(a) and 2(b) and a second usage position (first unfolded position, first open position) shown in Figures 3(a) and 3(b). The first extension tray 40 is rotatable around a pivot axis (rotation axis) X1. The second extension tray 30 is rotatable around a pivot axis (rotation axis) X2.

[0038] The state in which the first extension tray 40 is in the first retracted position and the second extension tray 30 is in the second retracted position is called the stored state of the extension tray section 14 (first state). The state in which the first extension tray 40 is in the first use position and the second extension tray 30 is in the second use position is called the deployed state of the extension tray section 14 (second state).

[0039] To move the extension tray 14 from the extended state to the retracted state, the user rotates the second extension tray 30 in the counterclockwise direction as shown in Figure 2(b). To move the extension tray 14 from the extended state to the retracted state, the user rotates the second extension tray 30 in the clockwise direction as shown in Figure 3(b).

[0040] In the extended tray section 14, the first extension tray 40 and the second extension tray 30 can support the sheet S discharged by the discharge roller pair 11 together with the discharge tray 12. On the other hand, in the retracted state of the extended tray section 14, the first extension tray 40 and the second extension tray 30 are retracted downwards compared to the extended state. It is preferable to retract the extended tray section 14 when the user does not use the extended tray section 14 or when transporting the image forming apparatus 1.

[0041] The first extension tray 40 has a top surface 41 as a third surface. The top surface 41 faces upward when the second extension tray 20 is in the second retracted position (Figure 2(a)(b)) and in the second use position (Figure 3(a)(b)).

[0042] The second extension tray 30 has a first surface 31 (fifth surface), a second surface 37 on the back side of the first surface 31, and ribs 36. The second surface 37 faces upward with respect to the Z-axis direction when the second extension tray 30 is in the second use position (Figure 3(a)(b)). The first surface 31 faces upward with respect to the Z-axis direction when the second extension tray 30 is in the second retracted position (Figure 2(a)(b)).

[0043] The ribs 36 are formed to protrude above the second surface 37 when the second extension tray 30 is in the second usage position (Figure 3(a)(b)). The ribs 36 are provided at both ends of the second surface 37 in the X-axis direction and extend in directions intersecting the X-axis direction. The tip surface 36a of the ribs 36 functions as a fourth surface capable of receiving the sheet S together with the upper surface 41 (third surface) of the first extension tray 40 when the second extension tray 30 is in the second usage position (Figure 3(a)(b)).

[0044] Furthermore, when the second extension tray 30 is in the second operating position (Figure 3(a)(b)), the second surface 37 of the second extension tray 30 extends downstream of the rib 36 in the sheet discharge direction D. Therefore, the second surface 37 can receive the sheet S downstream of the downstream end (36a1) of the rib 36 in the sheet discharge direction D.

[0045] In this embodiment, the first extension tray 40 and the second extension tray 30 are supported by the front door 13. An extension tray storage section 21 is formed on the upper surface of the front door 13 (the upper surface of the housing 1C), which is a recess that is recessed downward compared to the top surface 15 (second surface) of the front door 13. The extension tray storage section 21 forms a space for accommodating the first extension tray 40 in the first retracted position and the second extension tray 30 in the second retracted position.

[0046] In this embodiment, when the extension tray section 14 is stored, the second extension tray 30 and the first extension tray 40 are stored in the extension tray storage section 21 with the second extension tray 30 overlapping the first extension tray 40 (Figure 2(a)(b)). Also, when the extension tray section 14 is stored, the entire first extension tray 40 is covered by the second extension tray 30. In other words, the first extension tray 40 is not exposed when viewed from above in the vertical direction (Figure 2(a)).

[0047] When the extension tray section 14 is stored, the first surface 31, which is the upper surface of the second extension tray 30, forms a surface substantially identical to the top surface 15 of the front door 13. That is, when viewed in a direction perpendicular to both the sheet discharge direction D and the vertical direction (Z-axis direction) (X-axis direction), at least a part of the first surface 31 overlaps with the top surface 15 of the front door 13. When the extension tray section 14 is stored, the first surface 31 of the second extension tray 30 may protrude slightly from the top surface 15 of the front door 13, or it may be slightly recessed from the top surface 15. When the extension tray section 14 is stored, the first surface 31 of the second extension tray 30 may be parallel to the top surface 15 of the front door 13.

[0048] In the retracted state of the extension tray section 14, the first surface 31 of the second extension tray 30 can receive the lower surface of the sheet S together with the top surface 15 of the front door 13. That is, the first surface 31 of the second extension tray 30 is a fifth surface facing the opposite side of the tip surface 36a (fourth surface) of the rib 36, which will be described later, and functions as a fifth surface that receives the sheet discharged by the discharge roller pair 11 when the second extension tray 30 is in the second retracted position. Note that in the retracted state of the extension tray section 14, the tip surface 36a (fourth surface) of the rib 36 faces downward.

[0049] Furthermore, when the extension tray section 14 is in the retracted state, the first surface 31 of the second extension tray 30, together with the top surface 15 of the front door 13, forms the upper surface of the image forming apparatus 1. In this state, the first surface 31 and the upper surface 41 of the first extension tray 40 overlap at least partially when viewed in the direction of gravity. On the other hand, in this embodiment, when the extension tray section 14 is in the retracted state, the entire first extension tray 40 is covered by the second extension tray 30 when viewed in the direction of gravity, and the upper surface 41 of the first extension tray 40 does not come into contact with the sheet S.

[0050] The width Y1 (Figure 2(b)) of the extension tray storage section 21 (recess) in the sheet discharge direction D is shorter than the length Y2 (Figure 3(b)) when the extension tray section 14 is unfolded. The length Y2 is the length from the upstream end of the upper surface 41 (third surface) of the first extension tray 40 to the downstream end of the tip surface 36a (fifth surface) of the rib 36 in the sheet discharge direction D, when the first extension tray 40 is in the first use position and the second extension tray 30 is in the second use position. In this way, the first extension tray 40 and the second extension tray 30 can be housed in the extension tray storage section 21 (recess) with a short width Y1, so the configuration of this embodiment is advantageous for miniaturizing the image forming apparatus 1.

[0051] When the extension tray section 14 is stored, the entire first surface 31 does not necessarily need to form the same surface as the top surface 15 of the front door 13. For example, the upstream end of the first surface 31 in the sheet discharge direction D may be slightly inclined downwards, and the upstream end of the first surface 31 may be located below the top surface 15 of the front door 13. This configuration makes it less likely for the leading edge of the sheet S to get caught on the upstream end of the first surface 31.

[0052] In the unfolded state of the extension tray section 14 shown in Figures 3(a) and 3(b), at least a portion of the upper surface 41 (third surface) of the first extension tray 40 is located downstream of the discharge tray 12 (first surface) in the sheet discharge direction D and protrudes above the top surface 15 (second surface) of the front door 13. Also, in the unfolded state of the extension tray section 14, at least a portion of the upper surface 41 (third surface) of the first extension tray 40 is inclined upward toward the downstream direction D of the sheet discharge direction.

[0053] Furthermore, in the unfolded state of the extension tray section 14, at least a portion of the tip surface 36a (fourth surface) of the rib 36 of the second extension tray 30 protrudes above the discharge tray 12 (first surface) and the upper surface 41 (third surface) of the first extension tray 40. Also, in the unfolded state of the extension tray section 14, at least a portion of the tip surface 36a (fourth surface) of the rib 36 of the second extension tray 30 is located downstream of the upper surface 41 (third surface) of the first extension tray 40 in the sheet discharge direction D. Furthermore, in the unfolded state of the extension tray section 14, at least a portion of the tip surface 36a (fourth surface) of the rib 36 of the second extension tray 30 is inclined upward toward the downstream direction D of the sheet discharge direction D.

[0054] When the second extension tray 30 rotates from the second retracted position to the second use position, the first extension tray 40 is moved from the first retracted position to the first use position by the pressing rib 35 (interlocking part), which will be described later. Also, when the first extension tray 40 moves from the first retracted position to the first use position, at least a portion of the upper surface (third surface) of the first extension tray 40 moves upward. In particular, the downstream end of the upper surface (third surface) of the first extension tray 40 in the sheet discharge direction D moves upward.

[0055] In this way, when the extension tray section 14 is deployed, the upper surface 41 (third surface) of the first extension tray 40 and the tip surface 36a (fourth surface) of the rib 36 of the second extension tray 30 each form an inclined surface that, together with the discharge tray 12 (first surface), can receive the lower surface of the sheet S. The discharge roller pair 11 can transport the sheet S to a position where it contacts the upper surface 41 (third surface) of the first extension tray 40 and the tip surface 36a (fourth surface) of the rib 36 of the second extension tray 30 when the extension tray section 14 is deployed.

[0056] When the first extension tray 40 is in the first use position (Figure 3(b)), it is preferable that the position of at least a portion of the upper surface 41 (third surface) in the direction of gravity is higher than the position of the first surface 31 (fifth surface) when the second extension tray 30 is in the second retracted position (Figure 2(b)). In other words, when the extension tray section 14 is unfolded in the stored state, it is preferable that the upper surface 41 of the first extension tray 40 protrudes to a position higher than the position of the first surface 31 of the second extension tray 30, which is the upper surface of the extension tray section 14 in the stored state.

[0057] Furthermore, it is preferable that the second extension tray 30 rotates such that the end 36a1 of the tip surface 36a of the rib 36 that is farther from the rotation axis X2 of the second extension tray 30 straddles the rotation axis X2. In other words, when the second extension tray 30 is in the second retracted position (Figure 2(b)), it is preferable that the end 36a1 of the tip surface 36a (fourth surface) of the rib 36 that is farther from the rotation axis X2 is located upstream of the rotation axis X2 in the sheet discharge direction D. Also, when the second extension tray 30 is in the second use position (Figure 3(b)), it is preferable that the end 36a1 of the tip surface 36a (fourth surface) of the rib 36 is located downstream of the rotation axis X2 in the sheet discharge direction D.

[0058] Furthermore, when the second extension tray 30 is in the second retracted position, it is preferable that the end portion 36a1 of the tip surface 36a (fourth surface) of the rib 36 is located upstream of the downstream end 41a of the upper surface 41 (third surface) of the first extension tray 40 in the sheet discharge direction D (Figure 2(b)).

[0059] As shown in Figure 3(b), when viewed in the X-axis direction, the imaginary straight line drawn along the discharge tray 12 is defined as the extension line 16 of the discharge tray 12. If the inclination angle of the discharge tray 12 with respect to the horizontal plane (angle of inclination in the horizontal direction) is not constant, the extension line 16 refers to the imaginary straight line drawn along the region where the inclination angle of the discharge tray 12 is largest. For example, the discharge tray 12 may include a first inclined section 12a inclined at a first inclination angle with respect to the horizontal plane, and a second inclined section 12b downstream of the first inclined section 12a in the sheet discharge direction D, inclined at a second inclination angle smaller than the first inclination angle with respect to the horizontal plane. In this case, the extension line 16 is the imaginary straight line drawn along the first inclined section 12a.

[0060] Preferably, when the extension tray section 14 is deployed, the inclination angle of the tip surface 36a (fourth surface) of the rib 36 of the second extension tray 30 with respect to the horizontal plane, and the inclination angle of the upper surface 41 (third surface) of the first extension tray 40 with respect to the horizontal plane are close to the inclination angle of the extension line 16 of the discharge tray 12. This allows the sheet S to slide more smoothly along the tip surface 36a (fourth surface) of the rib 36 of the second extension tray 30 and the upper surface 41 (third surface) of the first extension tray 40 when the extension tray section 14 is deployed.

[0061] (Details of each extension tray) The details of the first extension tray 40 and the second extension tray 30 will be further explained using Figures 4(a) to 5(b). Figure 4(a) is an exploded perspective view showing the second extension tray 30 and the extension tray storage section 21. Figure 4(b) is a perspective view of the second extension tray 30 from the side of the second surface 37. Figure 5(a) is an exploded perspective view showing the first extension tray 40 and the extension tray storage section 21. Figure 5(b) is a perspective view of the first extension tray 40 from the back side of the top surface 41.

[0062] (1) Second extension tray As shown in Figures 4(a) and 4(b), the second extension tray 30 has a first surface 31, a second surface 37, a rib 36, a rotating hole 32, a first contact portion 33, a second contact portion 34, and a pressing rib 35.

[0063] The second extension tray 30 in this embodiment has a plate-like portion (tray body) including a first surface 31 and a second surface 37 on its reverse side. The second extension tray 30 in this embodiment also has a first rib 36 provided at one end of the plate-like portion in the direction of the rotation axis X2 of the second extension tray 30 (rotation axis direction), and a second rib 36 provided at the other end of the plate-like portion. Each rib 36 extends in a direction intersecting the rotation axis direction of the second extension tray 30. The number of ribs 36 may be one or two or more.

[0064] The pivot holes 32 are formed on both sides of the second extension tray 30 in the X-axis direction. In this embodiment, the pivot holes 32 are formed in each of the two ribs 36 that form the end face of the second extension tray 30 in the X-axis direction.

[0065] The two pivot holes 32 each engage with a pivot shaft 22 provided in the extension tray storage section 21. The second extension tray 30 is rotatable around a pivot axis X2 (second pivot axis) passing through the center of the pivot shaft 22. The pivot axis X2 of the second extension tray 30 is located downstream of the pivot axis X1 (first pivot axis) of the first extension tray 40. It is preferable that the pivot axis X1 extends along the pivot axis X2, and it is more preferable that the two pivot axes X1 are parallel. The direction of the pivot axis of the first extension tray 40 and the direction of the pivot axis of the second extension tray 30 may be perpendicular to both the sheet discharge direction D and the direction of gravity. A shaft portion may be provided in the second extension tray 30, and pivot holes that engage with the shaft portion may be provided in the extension tray storage section 21.

[0066] The first contact portion 33 and the second contact portion 34 are each formed at positions away from the rotation axis X2 of the second extension tray 30. In this embodiment, the first contact portion 33 is formed at one end of the second surface 37 in a direction intersecting the rotation axis X2, and the second contact portion 34 is formed at the other end of the second surface 37 in a direction intersecting the rotation axis X2. The first contact portion 33 can come into contact with the first contacted portion 23 provided on the extension tray storage portion 21. The second contact portion 34 can come into contact with the second contacted portion 24 provided on the extension tray storage portion 21.

[0067] In the stored state of the extension tray section 14 (Figure 2(b)), the second extension tray 30 is positioned by the contact between the first contact portion 33 and the first contacted portion 23. Specifically, the center of gravity of the second extension tray 30 in the second retracted position shown in Figure 2(b) is located upstream of the rotation axis X2 in the sheet discharge direction D. Therefore, a clockwise moment acts on the second extension tray 30 around the rotation axis X2 in Figure 2(b) due to its own weight. Against this moment, the first contacted portion 23 of the extension tray storage section 21 supports the first contact portion 33 of the second extension tray 30, thereby holding the second extension tray 30 in the second retracted position.

[0068] In the deployed state of the extension tray section 14 (Figure 3(b)), the second extension tray 30 is positioned by the contact between the second contact section 34 and the second contacted section 24. Specifically, the center of gravity of the second extension tray 30 in the second usage position shown in Figure 3(b) is located downstream of the rotation axis X2 in the sheet discharge direction D. Therefore, a counterclockwise moment acts on the second extension tray 30 around the rotation axis X2 in Figure 3(b) due to its own weight. Against this moment, the second contacted section 24 of the extension tray storage section 21 supports the second contact section 34 of the second extension tray 30, thereby holding the second extension tray 30 in the second usage position.

[0069] The pressing rib 35 protrudes from the plate-like portion of the second extension tray 30 in a direction intersecting the rotation axis X2 of the second extension tray 30 (upward in Figure 4). The pressing rib 35 rotates around the rotation axis X2 of the second extension tray 30 as the second extension tray 30 rotates. The pressing rib 35 functions as an interlocking part that moves the first extension tray 40 in conjunction with the rotation of the second extension tray 30.

[0070] In this embodiment, the pressing ribs 35 are arranged one on each side of the center of the second surface 37 in the direction of the rotation axis X2 of the second extension tray 30. In addition, in this embodiment, the two pressing ribs 35 are arranged between the two ribs 36 (the first rib and the second rib) in the direction of the rotation axis X2 of the second extension tray 30.

[0071] (2) First extension tray As shown in Figures 5(a) and 5(b), the first extension tray 40 has a top surface 41, a pivot shaft 42, a first contact portion 43, a pressed portion 44, a second contact portion 45, and a hook portion 46.

[0072] The pivot shafts 42 are formed on both sides of the first extension tray 40 in the X-axis direction. Each of the two pivot shafts 42 engages with a pivot hole 25 provided in the extension tray storage section 21. The first extension tray 40 is rotatable around a pivot axis X1 (first pivot axis) that passes through the center of the pivot shafts 42. Alternatively, a pivot hole may be provided in the first extension tray 40, and a pivot shaft that engages with the pivot hole may be provided in the extension tray storage section 21.

[0073] The pressed portion 44 is a force-receiving portion that receives force from the pressing rib 35 (interlocking portion) of the second extension tray 30. The pressed portion 44 is positioned downstream of the rotation axis X1 of the first extension tray 40 in the sheet discharge direction D. The first extension tray 40 is configured to move from a first retracted position to a first use position when the pressed portion 44 is pressed upward by the pressing rib 35 of the second extension tray 30 (Figure 3(b)). In other words, the first extension tray 40 has a force-receiving portion (pressed portion 44) positioned downstream of the rotation axis X1 (first rotation axis) in the sheet discharge direction D. The first extension tray 40 is configured to move from a first retracted position to a first use position when the force-receiving portion (pressed portion 44) receives an upward force from the interlocking portion (pressing rib 35).

[0074] Furthermore, when the second extension tray 30 is rotated from the second usage position toward the second retracted position, the pressing rib 35 moves downward and the pressure on the pressed portion 44 is released, so the first extension tray 40 moves from the first usage position toward the first retracted position by its own weight.

[0075] The first contact portion 43 and the second contact portion 45 are each formed at positions away from the rotation axis X1 of the first extension tray 40. In this embodiment, the first contact portion 43 is formed at one end of the upper surface 41 in a direction intersecting the rotation axis X1, and the second contact portion 45 is formed at the other end of the upper surface 41 in a direction intersecting the rotation axis X1. The first contact portion 43 can come into contact with the third contact portion 26 provided on the extension tray storage portion 21. The second contact portion 45 can come into contact with the fourth contact portion 27 provided on the extension tray storage portion 21.

[0076] In the stored state of the extension tray section 14 (Figure 2(b)), the first extension tray 40 is positioned by the contact between the first contact portion 43 and the third contacted portion 26. Specifically, the center of gravity of the first extension tray 40 in the first retracted position shown in Figure 2(b) is located downstream of the rotation axis X1 in the sheet discharge direction D. Therefore, a counterclockwise moment acts on the first extension tray 40 around the rotation axis X1 in Figure 2(b) due to its own weight. Against this moment, the third contacted portion 26 of the extension tray storage section 21 supports the first contact portion 43 of the first extension tray 40, thereby holding the first extension tray 40 in the first retracted position.

[0077] In the deployed state of the extension tray section 14 (Figure 3(b)), the first extension tray 40 is positioned by the contact between the pressing rib 35 and the pressed portion 44. Specifically, the center of gravity of the first extension tray 40 in the first use position shown in Figure 3(b) is located downstream of the rotation axis X1 in the sheet discharge direction D. Therefore, a counterclockwise moment acts on the first extension tray 40 around the rotation axis X1 in Figure 3(b) due to its own weight. Against this moment, the pressing rib 35 of the second extension tray 30 supports the pressed portion 44 of the first extension tray 40, thereby holding the first extension tray 40 in the first use position.

[0078] Furthermore, in the deployed state of the extension tray section 14 (Figure 3(b)), the second contact portion 45 of the first extension tray 40 faces the fourth contact portion 27 of the extension tray storage section 21. Suppose that in the deployed state of the extension tray section 14, an external force acts on the first extension tray 40 in a clockwise direction around the rotation axis X1 in Figure 3(b). Even in this case, the rotation of the first extension tray 40 is prevented by the second contact portion 45 of the first extension tray 40 contacting the fourth contact portion 27 of the extension tray storage section 21. In other words, the second contact portion 45 of the first extension tray 40 and the fourth contact portion 27 of the extension tray storage section 21 can prevent the first extension tray 40 from moving unintentionally (the posture of the first extension tray 40 from being disturbed) in the deployed state of the extension tray section 14.

[0079] The hook portion 46 protrudes from the surface of the first extension tray 40 opposite to the upper surface 41 (Figure 5(b)). The tip of the hook portion 46 is bent in a hook shape. The hook portion 46 can engage with a hook receiving projection 28 provided on the extension tray storage portion 21 (Figure 2(b)). The bending direction of the tip of the hook portion 46 and the protruding direction of the hook receiving projection 28 intersect with an arc centered on the rotation axis X1.

[0080] When the first extension tray 40 moves between the first retracted position (Figure 2(b)) and the first use position (Figure 3(b)), the hook portion 46 moves while elastically deforming, so that the tip of the hook portion 46 moves over the hook receiving projection 28. At this time, the resistance force that the hook portion 46 receives from the hook receiving projection 28 can provide a click sensation to the operation of the extension tray portion 14, thereby improving the operability of the extension tray portion 14. Here, the click sensation refers to, for example, when the user grasps the second extension tray 30 and rotates it from the second retracted position toward the second use position, the operating load felt by the user temporarily increases, and then the operating load decreases by the time the second extension tray 30 reaches the second use position.

[0081] (Summary of this example) In the unfolded state of the extension tray section 14, the upper surface 41 (third surface) of the first extension tray 40 and the tip surface 36a (fourth surface) of the rib 36 of the second extension tray 30 each form an inclined surface. The sheet S, which has been conveyed toward the discharge tray 12 and the extension tray section 14 by the discharge roller pair 11, comes into contact with the discharge tray 12 (first surface), the upper surface 41 (third surface) of the first extension tray 40, and the tip surface 36a (fourth surface) of the rib 36 of the second extension tray 30. Then, following the inclination of the discharge tray 12 (first surface), the upper surface 41 (third surface) of the first extension tray 40, and the tip surface 36a (fourth surface) of the rib 36 of the second extension tray 30, the sheet slides down toward the upstream side in the sheet discharge direction D.

[0082] Therefore, according to this embodiment, it is possible to provide a sheet discharge device and an image forming apparatus that can improve the consistency of the discharged sheets.

[0083] If the first extension tray 40 is not provided, the top surface of the housing 1C (the top surface 15 of the front door 13) and the sheet S will come into contact between the discharge tray 12 and the second extension tray 30. In that case, the sheet S will not slide down easily to the upstream side in the sheet discharge direction D, and the consistency of the sheet S in the discharge tray 12 may decrease. This obstruction of the movement of the sheet S along the slope of the discharge tray 12 is called sheet S leaning.

[0084] In this embodiment, when the extension tray section 14 is deployed, the upper surface 41 of the first extension tray 40 forms an inclined surface downstream of the discharge tray 12 and upstream of the tip surface 36a of the rib 36 of the second extension tray 30. This makes it less likely for the sheet S to lean and improves the consistency of the sheet S.

[0085] Furthermore, according to this embodiment, the pressing rib 35 (interlocking part) moves the first extension tray 40 from the first retracted position to the first use position in conjunction with the rotation of the second extension tray 30 from the second retracted position to the second use position. Therefore, both the first extension tray 40 and the second extension tray 30 can be moved from the retracted position to the use position by a simple operation of rotating the second extension tray 30, thereby improving usability.

[0086] Example 2 Another embodiment of the present disclosure (Embodiment 2) will be described with reference to Figures 6(a) to 8(c). In this embodiment, the configuration of the extension tray 50 differs from that of the extension tray 14 in Embodiment 1. Hereinafter, elements with reference numerals common to Embodiment 1 will have basically the same configuration and function as those described in Embodiment 1 unless otherwise specified, and the differences from Embodiment 1 will be mainly described.

[0087] Figure 6(a) is a perspective view showing the image forming apparatus 1 when the extension tray section 50 is in the retracted state. Figure 6(b) is a cross-sectional view of the extension tray section 50 shown in Figure 6(a) cut by a virtual plane perpendicular to the X-axis direction. Figure 7(a) is a perspective view showing the image forming apparatus 1 when the extension tray section 50 is in the unfolded state. Figure 7(b) is a cross-sectional view of the extension tray section 50 shown in Figure 7(a) cut by a virtual plane perpendicular to the X-axis direction. Figure 8(a) is an exploded perspective view showing the first extension tray 70, the second extension tray 60, and the extension tray storage section 51. Figure 8(b) is a perspective view of the second extension tray 60 viewed from the side of the second surface 67. Figure 8(c) is a perspective view of the first extension tray 70 viewed from the back side of the top surface 71.

[0088] As shown in Figures 6(a) to 7(b), the extension tray section 50 includes a first extension tray 70 and a second extension tray 60. The first extension tray 70 and the second extension tray 60 are positioned on the upper surface of the housing 1C (in this embodiment, the upper surface of the front door 13). The first extension tray 70 is movable (rotatable) between a first retracted position (first storage position, first closed position) shown in Figures 6(a) and 6(b) and a first usage position (first unfolded position, first open position) shown in Figures 7(a) and 7(b). The second extension tray 60 is rotatable between a second retracted position (first storage position, first closed position) shown in Figures 6(a) and 6(b) and a second usage position (first unfolded position, first open position) shown in Figures 7(a) and 7(b).

[0089] The state in which the first extension tray 70 is in the first retracted position and the second extension tray 60 is in the second retracted position is called the stored state of the extension tray section 50 (first state). The state in which the first extension tray 70 is in the first use position and the second extension tray 60 is in the second use position is called the deployed state of the extension tray section 50 (second state).

[0090] As shown in Figures 8(a) and 8(c), the first extension tray 70 has a top surface 71 as a third surface, a pivot shaft 72, a first contact portion 73, a pivot hole 74, a pressed portion 75 (force receiving portion), and a connecting portion 78.

[0091] As shown in Figures 8(a) and 8(b), the second extension tray 60 has a first surface 61 (fifth surface), a second surface 67 on the back side of the first surface 61, a pivot shaft 62, a groove 63, a second contact portion 64, a pressing rib 65 (interlocking portion), and a rib 66.

[0092] The pivot shaft 72 of the first extension tray 70 engages with the pivot hole 52 of the extension tray storage section 51. The first extension tray 70 rotates around the pivot axis X1 (first pivot axis) passing through the center of the pivot shaft 72. In other words, the first extension tray 70 is rotatably supported by the housing 1C. Alternatively, the first extension tray 70 may have a pivot hole, and the extension tray storage section 51 may have a pivot shaft that engages with the pivot hole.

[0093] The pivot shaft 62 of the second extension tray 60 engages with the pivot hole 74 of the first extension tray 70. The second extension tray 60 rotates around the pivot axis X2 (second pivot axis) passing through the center of the pivot shaft 62. In other words, the second extension tray 60 is rotatably supported by the first extension tray 70. The pivot axis X2 of the second extension tray 60 is movable (revolves) around the pivot axis X2 of the first extension tray 70. Alternatively, a pivot hole may be provided in the second extension tray 60, and a pivot shaft that engages with the pivot hole may be provided in the first extension tray 70.

[0094] In this embodiment, the first extension tray 70 and the second extension tray 60 are supported by the front door 13. An extension tray storage section 51 is formed on the upper surface of the front door 13 (the upper surface of the housing 1C), which is a recess that is recessed downward compared to the top surface 15 (second surface) of the front door 13. The extension tray storage section 51 forms a space for accommodating the first extension tray 70 in the first retracted position and the second extension tray 60 in the second retracted position.

[0095] In this embodiment, when the extension tray section 50 is stored, the second extension tray 60 and the first extension tray 70 are stored in the extension tray storage section 51 with the upper surface 71 of the first extension tray 70 aligned side-by-side with the first surface 61 of the second extension tray 60 (Figure 6(a)(b)). That is, when the first extension tray 70 is in the first retracted position and the second extension tray 60 is in the second retracted position, at least a portion of the upper surface 71 (third surface) of the first extension tray 70 is exposed to the outside of the second extension tray 60. In this state, the upper surface 71 (third surface) of the first extension tray 70, together with the first surface 61 (fifth surface) of the second extension tray 60, can receive the sheet S. Note that when the extension tray section 50 is stored, the tip surface 66a (fourth surface) of the rib 66 faces downward.

[0096] In the stored state, the upper surface 71 of the first extension tray 70 and the upper surface (first surface 61) of the second extension tray 60 form substantially the same surface as the top surface 15 of the front door 13. That is, when viewed in a direction perpendicular to both the sheet discharge direction D and the vertical direction (Z-axis direction) (X-axis direction), at least a portion of the upper surface 71 and at least a portion of the first surface 61 overlap with the top surface 15 of the front door 13. In the stored state of the extension tray section 50, the upper surface 71 of the first extension tray 70 and the upper surface (first surface 61) of the second extension tray 60 may protrude slightly from the top surface 15 of the front door 13, or may be slightly recessed from the top surface 15.

[0097] In this embodiment, the upper surface 71 of the first extension tray 70 is divided into two regions 71a and 71b that are separated in the X-axis direction (Figure 8(a)). The two regions 71a and 71b are connected by a connecting portion 78 that extends in the X-axis direction. When the extension tray 50 is stored, the connecting portion 78 of the first extension tray 70 is covered by the second extension tray 60, but the two regions 71a and 71b of the upper surface 71 are exposed from the second extension tray 60.

[0098] The width of the extension tray storage section 51 (recess) in the sheet discharge direction D is shorter than the length of the extension tray section 50 when it is unfolded. The length of the extension tray section 50 when it is unfolded is the length from the upstream end of the upper surface 71 (third surface) of the first extension tray 70 to the downstream end of the tip surface 66a (fifth surface) of the rib 66 in the sheet discharge direction D, when the first extension tray 70 is in the first use position and the second extension tray 60 is in the second use position.

[0099] When the extension tray section 50 is in the stored position, the first contact portion 73 of the first extension tray 70 contacts the first contact portion 53 (Figure 8(a)) of the extension tray storage section 51, thereby holding the first extension tray 70 in the first retracted position. Also, when the extension tray section 50 is in the stored position, the rib 66 of the second extension tray 60 contacts the connecting portion 78 of the first extension tray 70, thereby holding the second extension tray 60 in the second retracted position.

[0100] In the unfolded state of the extension tray section 50 shown in Figures 7(a) and 7(b), at least a portion of the upper surface 71 (third surface) of the first extension tray 70 is located downstream of the discharge tray 12 (first surface) in the sheet discharge direction D and protrudes above the top surface 15 (second surface) of the front door 13. Furthermore, in the unfolded state of the extension tray section 50, at least a portion of the upper surface 71 (third surface) of the first extension tray 70 is inclined upward toward the downstream direction D of the sheet discharge direction.

[0101] Furthermore, in the unfolded state of the extension tray section 50, at least a portion of the tip surface 66a (fourth surface) of the rib 66 of the second extension tray 60 protrudes above the discharge tray 12 (first surface) and the upper surface 71 (third surface) of the first extension tray 70. Also, in the unfolded state of the extension tray section 50, at least a portion of the tip surface 66a (fourth surface) of the rib 66 of the second extension tray 60 is located downstream of the upper surface 71 (third surface) of the first extension tray 70 in the sheet discharge direction D. Furthermore, in the unfolded state of the extension tray section 50, at least a portion of the tip surface 66a (fourth surface) of the rib 66 of the second extension tray 60 is inclined upward toward the downstream direction D of the sheet discharge direction D.

[0102] The user can rotate the second extension tray 60 from the second retracted position to the second usable position by placing their fingers in the groove 63 of the second extension tray 60, thereby extending the extension tray section 50 from the stored state to the deployed state.

[0103] When the second extension tray 60 rotates from the second retracted position to the second use position, the first extension tray 70 is moved from the first retracted position to the first use position by the pressing rib 65 (interlocking part), which will be described later. Also, when the first extension tray 70 moves from the first retracted position to the first use position, at least a portion of the upper surface (third surface) of the first extension tray 70 moves upward.

[0104] Specifically, when the second extension tray 60 rotates toward the second use position, the pressing rib 65 of the second extension tray 60 presses upward against the pressed portion 75 provided on the connecting portion 78 of the first extension tray 70, causing the first extension tray 70 to move toward the first use position. In other words, the first extension tray 70 has a force-receiving portion (pressed portion 75) located downstream of the rotation axis X1 (first rotation axis) in the sheet discharge direction D. The first extension tray 70 is configured to move from the first retracted position to the first use position when the force-receiving portion receives an upward force from the interlocking portion (pressing rib 65).

[0105] As the first extension tray 70 moves, the pivot axis X2 of the second extension tray 60 moves upward. The second extension tray 60 also rotates while sliding against the guide rib 54 of the extension tray storage section 51 at the second contact portion 64. The rotation of the second extension tray 60 stops when the second contact portion 64 abuts against the abutment portion 55 of the extension tray storage section 51, and is held in the second operating position by the abutment portion 55 (Figure 7(b)).

[0106] In this embodiment, the first extension tray 70 is rotatable around the pivot axis X1 relative to the housing 1C, and the second extension tray 60 is rotatable around the pivot axis X2 relative to the first extension tray 70. Therefore, in the deployed state of the extension tray section 50 (Figure 7(b)), the second contact section 64 of the second extension tray 60 abuts against the abutment section 55 to position it, thereby determining the orientation of both the first extension tray 70 and the second extension tray 60.

[0107] In the unfolded state of the extension tray section 50, the upper surface 71 (third surface) of the first extension tray 70 and the tip surface 66a (fourth surface) of the rib 66 of the second extension tray 60 each form an inclined surface that, together with the discharge tray 12 (first surface), can receive the lower surface of the sheet S. The discharge roller pair 11 can transport the sheet S to a position where it contacts the upper surface 71 (third surface) of the first extension tray 70 and the tip surface 66a (fourth surface) of the rib 66 of the second extension tray 60 in the unfolded state of the extension tray section 50.

[0108] When the first extension tray 70 is in the first use position (Figure 7(b)), it is preferable that the position of at least a portion of the upper surface 71 (third surface) in the direction of gravity is higher than the position of the first surface 61 (fifth surface) when the second extension tray 60 is in the second retracted position (Figure 6(b)). In other words, when the extension tray section 50 is unfolded in the stored state, it is preferable that the upper surface 71 of the first extension tray 70 protrudes to a position higher than the position of the first surface 61 of the second extension tray 60 and the upper surface 71 of the first extension tray 70, which are the upper surfaces of the extension tray section 50 in the stored state.

[0109] Furthermore, it is preferable that the second extension tray 60 rotates such that the end 66a1 of the tip surface 66a of the rib 66 that is farther from the rotation axis X2 of the second extension tray 60 straddles the rotation axis X2. In other words, when the second extension tray 60 is in the second retracted position (Figure 6(b)), it is preferable that the end 66a1 of the tip surface 66a (fourth surface) of the rib 66 that is farther from the rotation axis X2 is located upstream of the rotation axis X2 in the sheet discharge direction D. Also, when the second extension tray 60 is in the second use position (Figure 7(b)), it is preferable that the end 36a1 of the tip surface 66a (fourth surface) of the rib 66 is located downstream of the rotation axis X2 in the sheet discharge direction D.

[0110] Furthermore, when the second extension tray 60 is in the second retracted position, it is preferable that the end portion 66a1 of the tip surface 66a (fourth surface) of the rib 66 is located upstream of the downstream end 71c of the upper surface 71 (third surface) of the first extension tray 70 in the sheet discharge direction D (Figure 6(a)(b)).

[0111] When the extension tray section 50 is deployed, the inclination angle of the tip surface 66a (fourth surface) of the rib 66 of the second extension tray 60 with respect to the horizontal plane is preferably close to the inclination angle of the extension line 16 of the discharge tray 12 (Figure 7(b)). When the extension tray section 50 is deployed, the inclination angle of the upper surface 71 (third surface) of the first extension tray 70 with respect to the horizontal plane is preferably close to the inclination angle of the extension line 16 of the discharge tray 12.

[0112] (Summary of this example) In the unfolded state of the extension tray section 50, the upper surface 71 (third surface) of the first extension tray 70 and the tip surface 66a (fourth surface) of the rib 66 of the second extension tray 60 each form an inclined surface. The sheet S, which has been conveyed toward the discharge tray 12 and the extension tray section 50 by the discharge roller pair 11, comes into contact with the discharge tray 12 (first surface), the upper surface 71 (third surface) of the first extension tray 70, and the tip surface 66a (fourth surface) of the rib 66 of the second extension tray 60. Then, following the inclination of the discharge tray 12 (first surface), the upper surface 71 (third surface) of the first extension tray 70, and the tip surface 66a (fourth surface) of the rib 66 of the second extension tray 60, the sheet slides down toward the upstream side in the sheet discharge direction D.

[0113] Therefore, according to this embodiment, it is possible to provide a sheet discharge device and an image forming apparatus that can improve the consistency of the discharged sheets.

[0114] Furthermore, according to this embodiment, the pressing rib 65 (interlocking part) moves the first extension tray 70 from the first retracted position to the first use position in conjunction with the rotation of the second extension tray 60 from the second retracted position to the second use position. Therefore, both the first extension tray 70 and the second extension tray 60 can be moved from the retracted position to the use position by a simple operation of rotating the second extension tray 60, thereby improving usability.

[0115] Furthermore, according to this embodiment, even when the second extension tray 60 rotates between the second retracted position and the second use position, fluctuations in the lower end position of the second extension tray 60 are suppressed. In other words, the direction of movement of the second contact portion 64, which is the end of the second extension tray 60 in the direction intersecting the rotation axis X2, is restricted to the direction along the guide rib 54. Changes in the relative position of the rotation axis X2 and the second contact portion 64 in the Z-axis direction are absorbed by the movement of the rotation axis X2 due to the rotation of the first extension tray 70.

[0116] In Embodiment 1, the second extension tray 30 is rotatably supported by the housing 1C. In this case, the extension tray storage section 21 of the housing 1C is provided with space for the second contact portion 34 to move so that the end portion (second contact portion 34) of the second extension tray 60 does not interfere when the second extension tray 30 rotates (Figures 2(b) and 3(b)). On the other hand, in this embodiment, the change in the position of the end portion (second contact portion 64) of the second extension tray 60 when the second extension tray 60 rotates is suppressed, so the size of the extension tray storage section 51 in the Z-axis direction can be reduced, which is advantageous for miniaturizing the image forming apparatus 1 in the Z-axis direction.

[0117] (Other embodiments) The configuration for moving the first extension tray 40 in conjunction with the rotation of the second extension tray 30 is not limited to those described in Examples 1 and 2. For example, in Example 1, when the second extension tray 30 is rotated from the second retracted position to the second use position, the rib 36 may come into contact with a part of the first extension tray 40, lifting the downstream end of the first extension tray 40 in the sheet discharge direction D. In this case, a part of the tip surface 36a of the rib 36 (a part of the fourth surface) functions as an interlocking part.

[0118] Furthermore, in the embodiments described above, the first, second, third, fourth, and fifth surfaces may each be the tip surface of a rib formed on the surface of the member, or a surface without ribs. For example, the first surface may be the tip surface of a plurality of ribs formed on the discharge tray 12, each extending along the sheet discharge direction D and aligned in the X-axis direction. Also, for example, the third surface may be the tip surface of a rib formed on the upper surfaces 41 and 71 of the first extension trays 40 and 70. Also, for example, the fifth surface may be the tip surface of a rib formed on the first surfaces 31 and 61 of the second extension trays 30 and 60.

[0119] Summary of this disclosure This disclosure includes at least the following: (Composition 1) A housing having a discharge opening through which a sheet being discharged in the sheet discharge direction passes, and an upper surface, wherein the upper surface includes a first surface inclined upward toward the downstream direction of the sheet discharge, and a second surface provided downstream of the first surface in the sheet discharge direction, the first surface and the second surface configured to receive the sheet discharged from the discharge opening, and the angle between the second surface and a horizontal surface is smaller than the angle between the first surface and the horizontal surface, A first extension tray, positioned on the upper surface and movable between a first retracted position and a first use position, comprises a first extension tray having a third surface, A second extension tray, positioned on the upper surface and rotatable between a second retracted position and a second usage position, having a fourth surface and an interlocking part configured to move the first extension tray from the first retracted position to the first usage position when the second extension tray rotates from the second retracted position to the second usage position, A discharge roller configured to discharge the sheet from the discharge opening, the discharge roller capable of transporting the sheet to a position where it contacts the third and fourth surfaces when the first extension tray is in the first use position and the second extension tray is in the second use position, Equipped with, When the first extension tray is in the first operating position, at least a portion of the third surface is located downstream of the first surface and above the second surface in the sheet discharge direction, and is inclined upward toward the downstream direction of the sheet discharge. When the second extension tray is in the second operating position, at least a portion of the fourth surface is located downstream of the third surface in the sheet discharge direction, above the second and third surfaces, and is inclined upward toward the downstream direction of the sheet discharge direction. When the first extension tray moves from the first retracted position to the first use position, at least a portion of the third surface moves upward. A sheet discharge device characterized by the following features. (Configuration 2) When the second extension tray is in the second retracted position, the fourth surface faces downward. The second extension tray has a fifth surface configured to receive the sheet discharged by the discharge roller when the second extension tray is in the second retracted position. A sheet discharge device according to configuration 1, characterized by the above. (Composition 3) The position of at least a portion of the third surface in the direction of gravity when the first extension tray is in the first use position is higher than the position of the fifth surface when the second extension tray is in the second retracted position. The sheet discharge device according to configuration 2, characterized in that it is a sheet discharge device. (Composition 4) When the second extension tray is in the second retracted position, the end of the fourth surface that is farther from the rotation axis of the second extension tray is located upstream of the rotation axis in the sheet discharge direction. When the second extension tray is in the second operating position, the end of the fourth surface is located downstream of the rotation axis in the sheet discharge direction. A sheet discharge device according to any one of configurations 1 to 3, characterized by the above. (Composition 5) When the second extension tray is in the second retracted position, the end of the fourth surface furthest from the rotation axis of the second extension tray is located upstream of the downstream end of the third surface in the sheet discharge direction. A sheet discharge device according to any one of configurations 1 to 4, characterized by the above. (Composition 6) The first extension tray is configured to rotate around a first pivot axis that is perpendicular to both the sheet discharge direction and the gravity direction. The second extension tray is configured to rotate around a second rotation axis that is parallel to the first rotation axis and downstream of the first rotation axis in the sheet discharge direction. The first extension tray has a force-receiving portion located downstream of the first rotation axis in the sheet discharge direction, and is configured to move from a first retracted position to a first usage position when the force-receiving portion receives an upward force from the interlocking portion. A sheet discharge device according to any one of configurations 1 to 5, characterized by the above. (Composition 7) The second extension tray has a plate-like portion extending in the direction of the rotation axis of the second extension tray, a first rib projecting from one end of the plate-like portion in the direction of the rotation axis in a direction intersecting the direction of the rotation axis, and a second rib projecting from the other end of the plate-like portion in the direction of the rotation axis in a direction intersecting the direction of the rotation axis. The fourth surface is the tip surface of the first rib and the second rib, The interlocking portion is a rib positioned between the first rib and the second rib in the direction of the rotation axis, and protruding from the plate-like portion in a direction intersecting the direction of the rotation axis. A sheet discharge device according to configuration 6, characterized by the features described above. (Composition 8) When the first extension tray is in the first retracted position and the second extension tray is in the second retracted position, the third surface is covered by the second extension tray when viewed in the direction of gravity. A sheet discharge device according to any one of configurations 1 to 7, characterized by the above. (Composition 9) The first extension tray and the second extension tray are each rotatably supported by the housing. A sheet discharge device according to configuration 8, characterized by the above. (Composition 10) When the first extension tray is in the first retracted position and the second extension tray is in the second retracted position, at least a portion of the third surface is exposed to the outside of the second extension tray and is configured to receive the sheet discharged by the discharge roller. A sheet discharge device according to any one of configurations 1 to 7, characterized by the above. (Composition 11) The first extension tray is rotatably supported by the housing, and the second extension tray is rotatably supported by the first extension tray. A sheet discharge device according to configuration 10, characterized by the above. (Composition 12) The upper surface of the housing has a recess that is recessed downward compared to the second surface, and is formed therein for accommodating the first extension tray in the first retracted position and the second extension tray in the second retracted position. The width of the recess in the sheet discharge direction is shorter than the length from the upstream end of the third surface to the downstream end of the fourth surface in the sheet discharge direction when the first extension tray is in the first use position and the second extension tray is in the second use position. A sheet discharge device according to any one of configurations 1 to 11, characterized by the above. (Composition 13) The housing comprises a main body case having an opening for accessing the inside of the housing, and an opening / closing member that is movable between a position that closes the opening and a position that opens the opening. The first surface is provided on the main body case, The second surface and the recess are provided on the opening / closing member. A sheet discharge device according to configuration 12, characterized by the features described above. (Composition 14) The housing has a wall surface provided on the upstream side of the first surface in the sheet discharge direction and below the discharge opening. A sheet discharge device according to any one of configurations 1 to 13, characterized by the above. (Composition 15) A sheet discharge device as described in any one of configurations 1 to 14, The housing contains an image forming unit which forms an image on a sheet, Equipped with, The discharge roller discharges the sheet on which the image has been formed by the image forming unit. An image forming apparatus characterized by the following features. [Explanation of symbols]

[0120] 1C...Housing / 11...Discharge roller pair (discharge roller) / 11A...Discharge opening / 12...Discharge tray (first surface) / 12, 15, 18A...Top surface / 15...Top surface (second surface) / 30, 60...Second extension tray / 31, 61...First surface (fifth surface) / 35, 65...Pressing rib (interlocking part) / 36a, 66a...Rib tip surface (fourth surface) / 40, 70...First extension tray / 41, 71...Top surface (third surface)

Claims

1. A housing having a discharge opening through which a sheet being discharged in the sheet discharge direction passes, and an upper surface, wherein the upper surface includes a first surface inclined upward toward the downstream direction of the sheet discharge, and a second surface provided downstream of the first surface in the sheet discharge direction, the first surface and the second surface configured to receive the sheet discharged from the discharge opening, and the angle between the second surface and a horizontal surface is smaller than the angle between the first surface and the horizontal surface, A first extension tray, positioned on the upper surface and movable between a first retracted position and a first usage position, comprises a first extension tray having a third surface, A second extension tray, positioned on the upper surface and rotatable between a second retracted position and a second usage position, having a fourth surface and an interlocking part configured to move the first extension tray from the first retracted position to the first usage position when the second extension tray rotates from the second retracted position to the second usage position, A discharge roller configured to discharge the sheet from the discharge opening, the discharge roller capable of transporting the sheet to a position where it contacts the third and fourth surfaces when the first extension tray is in the first use position and the second extension tray is in the second use position, Equipped with, When the first extension tray is in the first operating position, at least a portion of the third surface is located downstream of the first surface and above the second surface in the sheet discharge direction, and is inclined upward toward the downstream direction of the sheet discharge. When the second extension tray is in the second operating position, at least a portion of the fourth surface is located downstream of the third surface in the sheet discharge direction, above the second and third surfaces, and is inclined upward toward the downstream direction of the sheet discharge. When the first extension tray moves from the first retracted position to the first use position, at least a portion of the third surface moves upward. A sheet discharge device characterized by the following features.

2. When the second extension tray is in the second retracted position, the fourth surface faces downward. The second extension tray has a fifth surface configured to receive the sheet discharged by the discharge roller when the second extension tray is in the second retracted position. The sheet discharge device according to feature 1.

3. The position of at least a portion of the third surface in the direction of gravity when the first extension tray is in the first use position is higher than the position of the fifth surface when the second extension tray is in the second retracted position. The sheet discharge device according to feature 2.

4. When the second extension tray is in the second retracted position, the end of the fourth surface that is farther from the rotation axis of the second extension tray is located upstream of the rotation axis in the sheet discharge direction. When the second extension tray is in the second operating position, the end of the fourth surface is located downstream of the rotation axis in the sheet discharge direction. The sheet discharge device according to feature 1.

5. When the second extension tray is in the second retracted position, the end of the fourth surface furthest from the rotation axis of the second extension tray is located upstream of the downstream end of the third surface in the sheet discharge direction. The sheet discharge device according to feature 1.

6. The first extension tray is configured to rotate around a first pivot axis that is perpendicular to both the sheet discharge direction and the gravity direction. The second extension tray is configured to rotate around a second rotation axis that is parallel to the first rotation axis and downstream of the first rotation axis in the sheet discharge direction. The first extension tray has a force-receiving portion located downstream of the first rotation axis in the sheet discharge direction, and is configured to move from a first retracted position to a first usage position when the force-receiving portion receives an upward force from the interlocking portion. The sheet discharge device according to feature 1.

7. The second extension tray has a plate-like portion extending in the direction of the rotation axis of the second extension tray, a first rib projecting from one end of the plate-like portion in the direction of the rotation axis in a direction intersecting the direction of the rotation axis, and a second rib projecting from the other end of the plate-like portion in the direction of the rotation axis in a direction intersecting the direction of the rotation axis. The fourth surface is the tip surface of the first rib and the second rib, The interlocking portion is a rib positioned between the first rib and the second rib in the direction of the rotation axis, and protruding from the plate-like portion in a direction intersecting the direction of the rotation axis. The sheet discharge device according to feature 6.

8. When the first extension tray is in the first retracted position and the second extension tray is in the second retracted position, the third surface is covered by the second extension tray when viewed in the direction of gravity. The sheet discharge device according to feature 1.

9. The first extension tray and the second extension tray are each rotatably supported by the housing. The sheet discharge device according to feature 8.

10. When the first extension tray is in the first retracted position and the second extension tray is in the second retracted position, at least a portion of the third surface is exposed to the outside of the second extension tray and is configured to receive the sheet discharged by the discharge roller. The sheet discharge device according to feature 1.

11. The first extension tray is rotatably supported by the housing, and the second extension tray is rotatably supported by the first extension tray. The sheet discharge device according to feature 10.

12. The upper surface of the housing has a recess that is recessed downward compared to the second surface, and is formed therein for accommodating the first extension tray in the first retracted position and the second extension tray in the second retracted position. The width of the recess in the sheet discharge direction is shorter than the length from the upstream end of the third surface to the downstream end of the fourth surface in the sheet discharge direction when the first extension tray is in the first use position and the second extension tray is in the second use position. The sheet discharge device according to feature 1.

13. The housing comprises a main body case having an opening for accessing the inside of the housing, and an opening / closing member that is movable between a position that closes the opening and a position that opens the opening. The first surface is provided on the main body case, The second surface and the recess are provided on the opening / closing member. The sheet discharge device according to feature 12.

14. The housing has a wall surface provided on the upstream side of the first surface in the sheet discharge direction and below the discharge opening. The sheet discharge device according to feature 1.

15. A sheet discharge device according to any one of claims 1 to 14, The housing contains an image forming unit which forms an image on a sheet, Equipped with, The discharge roller discharges the sheet on which the image has been formed by the image forming unit. An image forming apparatus characterized by the following features.

Images