Sheet support device and image forming apparatus

Abstract

This prevents the first and second wiring from breaking. [Solution] The sheet support portion comprises a main body having a bulge, a first support surface supported by the main body so as to be openable and closable and supporting a sheet, an opening, a pull-out portion supported by the sheet support portion so as to be pull-out in the pull-out direction and movable between a first position and a second position, a cover that rotates in conjunction with the movement of the pull-out portion between the first position and the second position and covers the opening, a detection portion for detecting a sheet, and wiring for transmitting a signal to the detection portion. At least a portion of the bulge enters the opening of the sheet support portion and enters the space surrounded by the recess of the cover when the sheet support portion is closed relative to the main body. The wiring is arranged so as not to overlap the cover when viewed in the direction normal to the first support surface.

Description

Technical Field

[0001] The present invention relates to a sheet support device for supporting a sheet and an image forming apparatus including the same.

Background Art

[0002] Conventionally, an image forming apparatus provided with a manual feed tray that can be opened and closed with respect to a device main body has been proposed (see Patent Document 1). A conveyance roller cover protrudes from the side of the device main body, and the manual feed tray has a tray main body and an auxiliary tray. The tray main body is provided with an opening that allows the conveyance roller cover to enter the inside of the tray main body, and the opening is covered with a rotatable opening cover. Further, the tray main body includes a first size detection mechanism for detecting the size of the placed sheet in the longitudinal direction, and the auxiliary tray includes a second size detection mechanism similar to the first size detection mechanism.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The first size detection mechanism and the second size detection mechanism of Patent Document 1 described above require wiring for transmitting signals and power. Although the tray main body is provided with a rotatable opening cover, if the opening cover catches on the wiring connected to the first size detection mechanism and the second size detection mechanism, the wiring may be damaged. Then, there is a risk that signals from the first size detection mechanism and the second size detection mechanism cannot be correctly transmitted.

[0005] Therefore, an object of the present invention is to provide a form of a sheet support device capable of suppressing disconnection of wiring and an image forming apparatus including the same. [Means for solving the problem]

[0006] One aspect of the present invention is a sheet support portion having a main body portion having a bulging portion, a first support surface that is openably and closably supported with respect to the main body portion and supports a sheet, and an opening provided on the first support surface, a drawer portion that is supported with respect to the sheet support portion so as to be retractable in the drawer direction and is movable between a first position in which at least a portion is housed inside the sheet support portion and a second position that is drawn downstream in the drawer direction from the first position, and having a second support surface that supports the sheet together with the first support surface when the drawer portion is in the second position, and a rotatably supported part of the sheet support portion that rotates in conjunction with the movement of the drawer portion between the first and second positions The sheet support device comprises a cover that moves and covers the opening, a detection unit that detects a sheet supported on the second support surface, and wiring connected to the detection unit and transmitting a signal output from the detection unit, wherein the cover has a recess that is recessed toward the interior of the sheet support unit through the opening, at least a part of the bulging portion enters the opening of the sheet support unit and enters the space surrounded by the recess of the cover when the sheet support unit is closed toward the main body, and the wiring is arranged so as not to overlap the cover when viewed in the direction normal to the first support surface, regardless of whether the pull-out portion is in the first position or the second position. [Effects of the Invention]

[0007] According to the present invention, it is possible to suppress the disconnection of the wiring. [Brief explanation of the drawing]

[0008] [Figure 1] A schematic diagram showing the image forming apparatus according to this embodiment. [Figure 2] (a) is a perspective view showing the seat support unit, and (b) is a front view showing the seat support unit. [Figure 3](a) is a perspective view showing the extension tray extended from the main tray, and (b) is a front view showing the extension tray extended from the main tray. [Figure 4] (a) is a perspective view showing the internal configuration of the main tray and extension tray, and (b) is a front view showing the internal configuration of the main tray and extension tray. [Figure 5] (a) is a perspective view showing the internal configuration of the main tray and extension tray when the extension tray is in the second position, and (b) is a front view showing the internal configuration of the main tray and extension tray when the extension tray is in the second position. [Figure 6] (a) is a schematic diagram showing the second guide section in the folded state, and (b) is a schematic diagram showing the second guide section in the extended state. [Modes for carrying out the invention]

[0009] [Overall structure] The image forming apparatus 1 according to this embodiment is an electrophotographic laser beam printer, and as shown in Figure 1, it has an image forming unit 10 for forming an image on a sheet S, a fixing unit 20, a cassette feeding unit 30, and a sheet support device 40.

[0010] Furthermore, an image forming apparatus includes printers, copiers, facsimile machines, and multifunction devices, and refers to a device that forms images on a sheet used as a recording medium based on image information input from an external PC or image information read from a document. In addition to the main unit that has the image forming function, an image forming apparatus may be connected to auxiliary equipment such as optional feeders, image readers, and sheet processing devices, and the entire system with such auxiliary equipment connected is also a type of image forming apparatus.

[0011] The image forming unit 10 comprises four process cartridges 11Y, 11M, 11C, and 11Bk, each forming toner images of four colors: yellow (Y), magenta (M), cyan (C), and black (Bk), respectively, and a scanner unit 15. The four process cartridges 11Y, 11M, 11C, and 11Bk have the same configuration except for the color of the image they form. Therefore, only the configuration and image forming process of process cartridge 11Y will be described, and the descriptions of process cartridges 11M, 11C, and 11Bk will be omitted.

[0012] The process cartridge 11Y includes a photosensitive drum 12, a charging roller 13, and a developing roller 14. The photosensitive drum 12 is constructed by coating the outer circumference of an aluminum cylinder with an organic photoconductive layer and is rotated by a drive motor (not shown). The image forming unit 10 is also provided with an intermediate transfer belt 18 wrapped around a drive roller 16 and a tension roller 17, and primary transfer rollers 19Y, 19M, 19C, and 19Bk are provided inside the intermediate transfer belt 18.

[0013] The fixing unit 20 includes a fixing film 21 that is heated by a heater (not shown) and a pressure roller 22 that presses against the fixing film 21. The cassette feeding unit 30 is located at the bottom of the image forming apparatus 1 and includes a cassette 31 for storing sheets and a feeding unit 32 for feeding sheets.

[0014] Next, the image forming operation of the image forming apparatus 1 configured in this way will be described. When an image signal is input to the scanner unit 15 from a personal computer (not shown), the scanner unit 15 irradiates a laser beam corresponding to the image signal onto the photosensitive drum 12 of the process cartridge 11Y.

[0015] At this time, the surface of the photosensitive drum 12 is uniformly charged to a predetermined polarity and potential in advance by the charging roller 13, and an electrostatic latent image is formed on the surface by irradiating laser light from the scanner unit 15. The electrostatic latent image formed on the photosensitive drum 12 is developed by the developing roller 14, and a yellow (Y) toner image is formed on the photosensitive drum 12.

[0016] Similarly, laser light is also irradiated from the scanner unit 15 to each photosensitive drum of the process cartridges 11M, 11C, and 11Bk, and magenta (M), cyan (C), and black (Bk) toner images are formed on each photosensitive drum. The toner images of each color formed on each photosensitive drum are transferred to the intermediate transfer belt 18 by the primary transfer rollers 19Y, 19M, 19C, and 19Bk, and are conveyed to the secondary transfer roller 25 by the intermediate transfer belt 18 rotated by the driving roller 16. Note that the image forming process for each color is performed at the timing of overlapping with the upstream toner image primarily transferred onto the intermediate transfer belt 18.

[0017] In parallel with this image forming process, the sheet S accommodated in the cassette 31 of the cassette feeder 30 is sent out by the feeding unit 32 and then conveyed to the registration roller pair 35. The sheet S whose skew is corrected by the registration roller pair 35 is conveyed to the main conveyance path 43 at a predetermined conveyance timing. Then, the full-color toner image on the intermediate transfer belt 18 is transferred to the sheet S by the secondary transfer bias applied to the secondary transfer roller 25.

[0018] The sheet S onto which the toner image has been transferred is given a predetermined heat and pressure by the fixing film 21 and the pressure roller 22 of the fixing unit 20, and the toner is melted and fixed (fixed). The sheet S that has passed through the fixing unit 20 is discharged to the discharge tray 27 by the discharge roller pair 26.

[0019] When performing double-sided printing to form images on both sides of the sheet S, the sheet S with an image formed on the first side is conveyed toward the double-sided conveyance path 41 by the reverse rotation of the discharge roller pair 26. The sheet S is conveyed by the double-sided conveyance roller pair 42 provided in the double-sided conveyance path 41 and merges into the main conveyance path 43. Then, the toner image on the intermediate transfer belt 18 is transferred to the second side of the sheet S opposite to the first side, and the sheet S is discharged to the discharge tray 27 by the discharge roller pair 26.

[0020] Further, the image forming apparatus 1 has an apparatus main body 1A in which the cassette feeding unit 30 and the like are accommodated, and a sheet support apparatus 40 is supported by the apparatus main body 1A so as to be openable and closable. The sheet support apparatus 40 has a main body portion 50, a transfer unit 60, and a sheet support unit 70. The main body portion 50 is supported by the apparatus main body 1A so as to be openable and closable about a rotation axis 51. The transfer unit 60 is supported by the main body portion 50 so as to be openable and closable about a rotation axis 61, and supports the secondary transfer roller 第25等.

[0021] A main conveyance path 43 is formed between the apparatus main body 1A and the transfer unit 60, and when the transfer unit 60 is opened with respect to the apparatus main body 1A together with the main body portion 50, the main conveyance path 43 is opened. Also, when the transfer unit 60 is opened with respect to the main body portion 50 in this state, the double-sided conveyance path 41 between the main body portion 50 and the transfer unit 60 is opened. By configuring the main conveyance path 43 and the double-sided conveyance path 41 to be openable in this way, the jam processing performance can be improved.

[0022] The double-sided conveyance roller pair 42 has a first roller 42a provided in the transfer unit 60 and a second roller 42b provided in the main body portion 50 as a roller and a bulging portion. Note that either one of the first roller 42a and the second roller 42b is a driving roller driven by a driving source not shown, and the other is a driven roller that rotates following the driving roller.

[0023] [Sheet Support Unit] It should be noted that in the original text, "二次転写ローラ25等を支持している." seems to have an unclear "第25", which might be a typo. I translated it as "secondary transfer roller 第25等" to maintain the original form. You may want to double-check this part in the original context.Next, the configuration of the sheet support unit 70 will be described using Figures 1 to 3(b). Figure 2(a) is a perspective view showing the sheet support unit 70, and Figure 2(b) is a front view showing the sheet support unit 70. Figure 3(a) is a perspective view showing the extension tray 73 pulled out from the main tray 72, and Figure 3(b) is a front view showing the extension tray 73 pulled out from the main tray 72.

[0024] As shown in Figures 1 to 3(b), the sheet support unit 70 is configured to be rotatable relative to the main body 50 around a pivot axis 71. The sheet support unit 70 includes a main tray 72, an extension tray 73 that is supported so as to be retractable relative to the main tray 72 in the retraction direction DD, and a pair of side restricting plates 74L and 74R.

[0025] The main tray 72, which serves as the sheet support, is supported by the main body 50 so as to be openable and closable around the aforementioned pivot axis 71, and has a first support surface 72a that supports the sheet, and an opening 72b provided on the first support surface 72a. The opening 72b extends in the width direction W, which is an orthogonal direction perpendicular to the pulling direction DD, and is formed in a rectangular shape.

[0026] A pair of side regulating plates 74L and 74R are supported so as to be movable in the width direction W relative to the main tray 72, and regulate the position of the sheet supported on the first support surface 72a in the width direction W. The pair of side regulating plates 74L and 74R each have a rack gear that meshes with a pinion gear 75 (Figure 4(a)(b)) provided inside the main tray 72, and these rack gears and pinion gears 75 interlock to move toward or away from each other. The sheet supported on the first support surface 72a and the second support surface 73a can be fed by a pickup roller (not shown) provided on the main body 50, and the fed sheet joins the main transport path 43.

[0027] The extension tray 73 is configured to be movable between a first position (shown in Figures 2(a) and 2(b)) in which at least a portion is stored inside the main tray 72, and a second position (shown in Figures 3(a) and 3(b)) in which it is pulled out downstream in the pulling direction DD from the first position. The extension tray 73, as a pull-out section, also has a second support surface 73a that supports the sheet together with the first support surface 72a of the main tray 72 when the extension tray 73 is in the second position. When the user places, for example, plain paper such as A4 size onto the sheet support unit 70, the extension tray 73 is positioned in the first position. On the other hand, when the user places, for example, a long sheet longer than A4 size onto the sheet support unit 70, the extension tray 73 is positioned in the second position. This allows long sheets to be stably placed on the sheet support unit 70. A long sheet is, for example, a sheet with a long side length of 500 mm or more.

[0028] A groove 73b is provided on the second support surface 73a of the extension tray 73, and the groove 73b is located opposite the opening 72b of the main tray 72 when the extension tray 73 is in the first position.

[0029] Furthermore, the main tray 72 is supported by a cover 76 that is rotatable around a pivot shaft 76a extending in the width direction W. The cover 76 is positioned to cover the opening 72b of the main tray 72. The pivot shaft 76a may be provided on the cover 76 or on the main tray 72. If the pivot shaft is provided on the main tray 72, the cover 76 is provided with an engaging portion that engages with the pivot shaft.

[0030] The cover 76 has a recess 76b that is recessed toward the interior of the main tray 72 through the opening 72b. Here, the normal direction ND is the direction normal to the first support surface 72a of the main tray 72, and the direction toward the interior of the main tray 72 from the first support surface 72a. The normal direction ND is perpendicular to both the pull-out direction DD and the width direction W. In this case, the opening 72b opens in the normal direction ND, and the recess 76b is recessed in the normal direction ND. That is, the cover 76 has a cross section perpendicular to the width direction W that is approximately V-shaped.

[0031] The cover 76 is positioned to cover the opening 72b when the extension tray 73 is in the first or second position. For example, the cover 76 is positioned in a standby position that covers the opening 72b by abutting against a stopper provided near the opening 72b of the main tray 72 in the direction of gravity. Alternatively, the cover 76 may be biased to the standby position by a biasing unit. This prevents foreign matter such as dust from entering the inside of the main tray 72. It also prevents the sheet from getting caught in the opening 72b when the sheet is set in the sheet support unit 70 or when the sheet set in the sheet support unit 70 is fed.

[0032] [Internal configuration of the tray] Next, the internal configuration of the main tray 72 and extension tray 73 will be described using Figures 4(a) to 5(b). Figure 4(a) is a perspective view showing the internal configuration of the main tray 72 and extension tray 73, and Figure 4(b) is a front view showing the internal configuration of the main tray 72 and extension tray 73. Figure 5(a) is a perspective view showing the internal configuration of the main tray 72 and extension tray 73 when the extension tray 73 is in the second position, and Figure 5(b) is a front view showing the internal configuration of the main tray 72 and extension tray 73 when the extension tray 73 is in the second position.

[0033] Note that in Figures 4(a) to 5(b), the top plate including the first support surface 72a of the main tray 72, the top plate including the second support surface 73a of the extension tray 73, and the side restrictor plate 74R are omitted from the display. The main tray 72 and the extension tray 73 are each formed in a box shape with an internal space.

[0034] As shown in Figures 4(a) to 5(b), a second detection sensor 78 is mounted on the bottom plate 77 of the main tray 72. The second detection sensor 78, as the second detection unit, is positioned approximately in the center of the bottom plate 77 in the width direction W. The second detection sensor 78 has a sensor part 78a and a light-shielding part 78b.

[0035] The sensor unit 78a has a light-emitting unit that emits light and a light-receiving unit that receives light emitted from the light-emitting unit. The light-shielding unit 78b has a contact unit 78b1 that can contact a sheet supported on the first support surface 72a and a shielding unit 78b2 that can shield the optical path between the light-emitting unit and the light-receiving unit, and is rotatably supported. The light-shielding unit 78b is positioned so that the contact unit 78b1 protrudes above the first support surface 72a (see Figure 2(a)), at which point the optical path of the sensor unit 78a is shielded by the shielding unit 78b2, and the sensor unit 78a is OFF. Then, when the sheet is placed on the first support surface 72a, the contact unit 78b1 is pressed downward by the sheet, causing the light-shielding unit 78b to rotate. As a result, the shielding unit 78b2 retracts from the optical path, and the sensor unit 78a is turned ON.

[0036] Furthermore, a first detection sensor 80 is attached to the bottom plate 79 of the extension tray 73. The detection unit and the first detection sensor 80 as the first detection unit are positioned approximately in the center of the bottom plate 79 in the width direction W. The first detection sensor 80 has the same configuration as the second detection sensor 78 and includes a sensor unit 80a and a light-shielding unit 80b. The light-shielding unit 80b has a contact unit 80b1 that can contact a sheet supported on the second support surface 73a and a shielding unit 80b2 that can shield the optical path between the light-emitting unit and the light-receiving unit, and is rotatably supported. The light-shielding unit 80b is positioned so that the contact unit 80b1 protrudes above the second support surface 73a (see Figure 3(a)), and at this time, the optical path of the sensor unit 80a is shielded by the shielding unit 80b2, and the sensor unit 80a is turned OFF. Then, the sheet is placed on the second support surface 73a, and the contact portion 80b1 is pressed downward by the sheet, causing the light-shielding portion 80b to rotate. As a result, the shielding portion 80b2 retracts from the optical path, and the sensor portion 80a turns ON.

[0037] Thus, the second detection sensor 78 can detect a sheet supported on the first support surface 72a, and the first detection sensor 80 can detect a sheet supported on the second support surface 73a. For example, the following can be detected using the first detection sensor 80 and the second detection sensor 78: When both the first detection sensor 80 and the second detection sensor 78 are OFF, it can be detected that no sheet is supported (placed) on the sheet support unit 70. Also, when the second detection sensor 78 is ON and the first detection sensor 80 is OFF, it can be detected that plain paper such as A4 size is supported on the first support surface 72a. Also, when both the first detection sensor 80 and the second detection sensor 78 are ON, it can be detected that a long sheet is supported on the sheet support unit 70.

[0038] Furthermore, the cover 76 is positioned between the first detection sensor 80 and the second detection sensor 78 in the pull-out direction DD. In addition, the first detection sensor 80 and the second detection sensor 78 are positioned to overlap with the cover 76 in the width direction W.

[0039] As shown in Figure 4(a), the extension tray 73 has a wall portion 81 that constitutes the upstream side in the pulling direction. The wall portion 81 has a first wall 81a and a second wall 81b that extend in the width direction W, and a protruding portion 81c that is positioned between the first wall 81a and the second wall 81b in the width direction W. Note that the first wall 81a and the second wall 81b do not necessarily have to extend parallel to the width direction W, but may extend in a direction along the width direction W.

[0040] The protruding portion 81c connects the first wall 81a and the second wall 81b and is configured to protrude downstream in the pulling direction DD from the first wall 81a and the second wall 81b. Furthermore, the protruding portion 81c is configured not to interfere with the second detection sensor 78 when the extension tray 73 is in the first position. That is, at least a portion of the second detection sensor 78 is located downstream in the pulling direction DD from the first wall 81a and the second wall 81b and is located within the space SP1 enclosed by the protruding portion 81c when the extension tray 73 is in the first position.

[0041] In this way, by forming a protrusion 81c on the wall portion 81, the wall portion 81 can be brought closer to the second detection sensor 78, and the sheet support unit 70 can be miniaturized in the pulling direction DD.

[0042] Here, the cover 76, which is rotatably supported on the main tray 72, rotates as the recess 76b is pressed against the wall portion 81 of the extension tray 73 when the extension tray 73 moves between a first position and a second position. More specifically, when the extension tray 73 moves from the first position to the second position, the protruding portion 81c of the wall portion 81 first presses against the upstream slope of the recess 76b in the pulling direction DD, causing the cover 76 to rotate upward from the standby position around the pivot axis 76a. Then, when the first wall 81a and the second wall 81b of the wall portion 81 pass the cover 76, the cover 76 returns to the standby position.

[0043] Furthermore, when the extension tray 73 moves from the second position to the first position, the first wall 81a and the second wall 81b of the wall portion 81 first press against the slope on the downstream side of the recess 76b in the pulling direction DD, causing the cover 76 to rotate upward from the standby position around the pivot axis 76a. Then, when the protruding portion 81c of the wall portion 81 passes the cover 76, the cover 76 returns to the standby position.

[0044] Thus, the cover 76 is configured to rotate in conjunction with the movement of the extension tray 73 between the first and second positions. In other words, the cover 76 is configured to rotate so as to move out of the way of movement of the extension tray 73 when the extension tray 73 moves between the first and second positions.

[0045] As shown in Figure 1, when the sheet support unit 70 is closed to the main body 50, at least a portion of the second roller 42b of the double-sided transport roller pair 42 enters the opening 72b of the main tray 72. Also, at least a portion of the second roller 42b enters the space SP2 surrounded by the recess 76b of the cover 76. By positioning the opening 72b and the recess 76b of the cover 76 at positions corresponding to the second roller 42b in this way, the sheet support device 40 can be miniaturized.

[0046] [Wiring configuration] Next, the arrangement of the wiring connected to the first detection sensor 80 and the second detection sensor 78 will be described using Figures 4(a) to 6(b). Figure 6(a) is a schematic diagram showing the second guide portion 95 in a folded state, and Figure 6(b) is a schematic diagram showing the second guide portion 95 in an extended state.

[0047] As shown in Figures 4(a) to 5(b), the sensor portion 78a of the second detection sensor 78 is connected to the second wiring, which is the second wire bundle 111, and the sensor portion 80a of the first detection sensor 80 is connected to the wiring and the first wiring, which is the first wire bundle 121. These first wire bundles 121 and 2 wire bundles 111 are connected to a control unit (not shown) provided in the main body 50 or the device body 1A, and transmit the signals output from the first detection sensor 80 and the second detection sensor 78 to the control unit, respectively. In addition, the first wire bundles 121 and 2 wire bundles 111 supply power to the first detection sensor 80 and the second detection sensor 78.

[0048] The sheet support unit 70 has a wire bundle guide unit 90 that guides the first wire bundle 121 and the second wire bundle 111. The wire bundle guide unit 90 has a first guide portion 91 that guides the second wire bundle 111 and a second guide portion 95 that guides the first wire bundle 121.

[0049] The first guide section 95 is provided on the bottom plate 77 of the main tray 72. The first guide section 95 has a first straight section 92, a second straight section 93, and a third straight section 94. The first straight section 92 and the third straight section 94 extend parallel to the drawer direction DD, and the second straight section 93 extends parallel to the width direction W and connects the first straight section 92 and the third straight section 94. In this way, the first guide section 95 is formed in a crank shape as a whole.

[0050] The second wire bundle 111, connected to the sensor portion 78a of the second detection sensor 78, is sequentially guided toward a control unit (not shown) by the first straight portion 92, the second straight portion 93, and the third straight portion 94. The first guide portion 95 is located on one end side of the main tray 72 (upper side in Figure 4(b)) in the width direction W, and the second wire bundle 111 is guided toward the aforementioned one end side by the first guide portion 95.

[0051] In this embodiment, the first straight section 92, the second straight section 93, and the third straight section 94 are each composed of ribs extending from the base plate 77 and facing each other. Furthermore, the first straight section 92 and the second straight section 93 guide only the second wire bundle 111, while the third straight section 94 guides both the second wire bundle 111 and the first wire bundle 121.

[0052] The first wire bundle 121 connected to the sensor portion 80a of the first detection sensor 80 has a first portion 121a that extends from the sensor portion 80a upstream in the pulling direction DD toward one end in the width direction W (upper side in Figure 4(b)). The first wire bundle 121 also has a second portion 121b that is continuous with the first portion 121a and extends along the side wall 82 of the extension tray 73. These first portion 121a and second portion 121b of the first wire bundle 121 may be guided by ribs or the like, as described above for the first guide portion 95.

[0053] The first bundle of wires 121 that exits the outlet 83 of the extension tray 73 is guided by the second guide section 95 and the third straight section 94. The second guide section 95, as a guide section, has a first guide member 96, a second guide member 97, a link member 98, and a spring 99 as a biasing section, as shown in Figure 6(a). The first guide member 96 guides the first bundle of wires 121. The second guide member 97 guides the first bundle of wires 121 and is positioned downstream of the first guide member 96 in the pulling direction DD. The link member 98 connects the first guide member 96 and the second guide member 97. The first guide member 96 is rotatable around the link axis 98a relative to the link member 98. The second guide member 97 is rotatable around the link axis 98b relative to the link member 98.

[0054] Furthermore, as shown in Figures 4(b) and 5(b), the first guide member 96 is configured to be rotatable around a pivot axis 96a, and the second guide member 97 is configured to be rotatable around a pivot axis 97a. The pivot axis 96a is provided, for example, on the main tray 72, and the pivot axis 97a is provided, for example, on the extension tray 73. The spring 99 is locked to the link member 98 and the main tray 72, and biases the second guide portion 95 to the folded state shown in Figure 6(a). That is, the spring 99 biases the link member 98 in the direction in which the second guide portion 95 is folded. Note that the link member 98 and the spring 99 are omitted in Figures 4(a) to 5(b).

[0055] As shown in Figures 4(a)(b) and 6(a), when the extension tray 73 is in the first position, the second guide portion 95 is in a folded state. When the extension tray 73 moves from the first position to the second position, the second guide portion 95 extends against the biasing force of the spring 99, as shown in Figures 5(a)(b) and 6(b). When the second guide portion 95 is extended, its length in the extension direction DD is the first length L1, and when it is folded, its length in the extension direction DD is the second length L2. That is, when the extension tray 73 moves from the second position to the first position, the second guide portion 95 is folded so that its length in the extension direction DD changes from the first length L1 to the second length L2. At this time, the first guide member 96 and the second guide member 97 rotate relative to the link member 98.

[0056] In this manner, the first wire bundle 121 and the second wire bundle 111, guided by the wire bundle guide unit 90, are positioned in the width direction W on one end side (upper side in Figure 4(b)) of the main tray 72 and the extension tray 73.

[0057] Furthermore, the first wire bundle 121 and the second wire bundle 111 are positioned so as not to overlap with the cover 76 when viewed in the normal direction ND, regardless of whether the extension tray 73 is in the first or second position. As a result, the first wire bundle 121 and the second wire bundle 111 do not interfere with the cover 76, which rotates in conjunction with the extension tray 73, and the cover 76 does not get caught on the first wire bundle 121 and the second wire bundle 111. This prevents the first wire bundle 121 and the second wire bundle 111 from breaking. In addition, the sheet support unit 70 can be made smaller in the normal direction ND.

[0058] Furthermore, since the opening 72b and the recess 76b of the cover 76 are positioned to correspond to the second roller 42b of the main body 50, the sheet support device 40 can be made smaller when the sheet support unit 70 is closed relative to the main body 50. In addition, since the opening 72b is covered by the cover 76, it is possible to prevent foreign matter such as dust from falling into the opening 72b and causing malfunctions in the second detection sensor 78 located inside the main tray 72.

[0059] Furthermore, when the sheet support unit 70 is closed relative to the main body 50, the cover 76 may be pressed by the second roller 42b. This reduces the gap between the cover 76 and the opening 72b, thereby further suppressing the entry of foreign matter into the opening 72b. In addition, the extension tray 73 is provided with a groove 73b that is positioned to face the cover 76 when the extension tray 73 is in the first position, so that the rotation of the cover 76 is not restricted by the extension tray 73 in the first position.

[0060] <Other Embodiments> In the above-described embodiment, both the first wire bundle 121 and the second wire bundle 111 were guided to be closer to one end (upper side in Figure 4(b)) in the width direction W of the main tray 72 and the extension tray 73, but the invention is not limited to this. For example, the second wire bundle 111 may be guided to be closer to one end (width direction W) of the main tray 72 and the extension tray 73, and the first wire bundle 121 may be guided to the other end (width direction W) of the main tray 72 and the extension tray 73. In any case, the first wire bundle 121 and the second wire bundle 111 are arranged so as not to overlap the cover 76 when viewed in the normal direction ND.

[0061] Furthermore, in the above-described embodiment, at least a portion of the second roller 42b was configured to enter the opening 72b and the recess 76b of the cover 76 when the sheet support unit 70 was closed relative to the main body 50, but the invention is not limited to this. For example, a roller cover that covers the second roller 42b may be provided near the second roller 42b, and the roller cover may be configured to enter the opening 72b and the recess 76b of the cover 76. Thus, the member provided on the main body 50 that can enter the opening 72b and the recess 76b of the cover 76 is not limited to a roller and can be anything.

[0062] Furthermore, in the above-described embodiment, the cover 76 was configured to rotate by being pressed by the wall portion 81 of the extension tray 73, but the invention is not limited to this. For example, the cover 76 may be connected to the extension tray 73 via a link mechanism and configured to rotate in conjunction with the movement of the extension tray 73 by the link mechanism.

[0063] Furthermore, in the above-described embodiment, the first wire bundle 121 and the second wire bundle 111 were mainly guided by ribs facing each other, but the invention is not limited to this. For example, instead of ribs, the first wire bundle 121 and the second wire bundle 111 may be guided by harness guides or the like, which are separate from the main tray 72 and extension tray 73.

[0064] Furthermore, in the above-described embodiment, the second guide portion 95 was structured to be folded via the link member 98, but the invention is not limited to this. For example, the second guide portion 95 may be formed in a spiral shape and be expandable and contractible.

[0065] Furthermore, although a protrusion 81c was formed on the wall portion 81 of the extension tray 73 in the above-described embodiment, the invention is not limited to this. For example, the protrusion 81c may be omitted, and the wall portion 81 may be formed only by a wall that is flush with the first wall 81a and the second wall 81b. Also, even when a protrusion 81c is provided on the wall portion 81, the shape of the protrusion 81c is not limited, and for example, the protrusion 81c may have a curved surface. [Explanation of Symbols]

[0066] 1: Image forming apparatus / 10: Image forming unit / 40: Sheet support device / 42b: Bulging part, roller (second roller) / 50: Main body / 72: Sheet support unit (main tray) / 72a: First support surface / 73: Pull-out part (extension tray) / 73a: Second support surface / 76: Cover / 76b: Recess / 78: Second detection unit (second detection sensor) / 80: Detection unit, first detection unit (first detection sensor) / 81: Wall part / 8 1a: First wall / 81b: Second wall / 81c: Protruding part / 95: Guide part (second guide part) / 96: First guide member / 97: Second guide member / 98: Link member / 99: Biasing part (spring) / 111: Second wiring (second bundle) / 121: Wiring, first wiring (first bundle) / DD: Pull-out direction / L1: First length / L2: Second length / ND: Normal direction / SP1, SP2: Space / W: Orthogonal direction (width direction)

Claims

1. A main body having a bulging portion, A sheet support portion having a first support surface that is openably and closably supported with respect to the main body and supports the sheet, and an opening provided on the first support surface, A pull-out section is supported so as to be pullable out in the pull-out direction relative to the sheet support section and is movable between a first position in which at least a portion is housed inside the sheet support section and a second position which is pulled out downstream in the pull-out direction from the first position, and the pull-out section has a second support surface that supports the sheet together with the first support surface when the pull-out section is in the second position, The cover is rotatably supported by the seat support portion and rotates in conjunction with the movement of the drawer portion between the first position and the second position, and covers the opening. A detection unit for detecting the sheet supported on the second support surface, Wiring connected to the detection unit and transmitting signals output from the detection unit, Equipped with, The cover has a recess that is recessed toward the interior of the seat support portion through the opening, At least a portion of the bulging portion enters the opening of the sheet support portion and enters the space surrounded by the recess of the cover when the sheet support portion is closed to the main body portion. The wiring is arranged such that, regardless of whether the lead-out portion is located in the first or second position, it does not overlap the cover when viewed in the direction normal to the first support surface. A sheet support device characterized by the following features.

2. The detection unit and the wiring are, respectively, a first detection unit and a first wiring. A second detection unit that detects the sheet supported on the first support surface, The device further includes a second wiring that is connected to the second detection unit and transmits signals output from the second detection unit, The sheet support device according to feature 1.

3. The cover is positioned between the first detection unit and the second detection unit in the pulling direction. The sheet support device according to feature 2.

4. The first detection unit and the second detection unit are positioned to overlap with the cover in an orthogonal direction that is perpendicular to both the extraction direction and the normal direction. The sheet support device according to feature 2.

5. The first and second wirings are arranged on one end side of the sheet support portion and the pull-out portion in an orthogonal direction perpendicular to both the pull-out direction and the normal direction. The sheet support device according to feature 2.

6. The device further includes a guide section for guiding the first wiring, The guide portion is folded such that, as the pull-out portion moves from the second position to the first position, its length in the pull-out direction changes from a first length to a second length that is shorter than the first length. The sheet support device according to feature 2.

7. The guide portion includes a first guide member that guides the first wiring, a second guide member that guides the first wiring and is positioned downstream of the first guide member in the pulling direction, and a link member that connects the second guide member and the second guide member. The first guide member and the second guide member rotate relative to the link member when the pull-out portion moves from the second position to the first position. The sheet support device according to feature 6.

8. The system further includes a biasing part that biases the link member in the direction in which the guide part folds. The sheet support device according to feature 7.

9. The cover rotates as the recess is pressed by the pull-out portion when the pull-out portion moves between the first and second positions. The sheet support device according to feature 2.

10. The aforementioned drawer portion has a wall portion that can abut against the recess, The wall portion comprises a first wall and a second wall, respectively, extending along orthogonal directions perpendicular to both the drawing direction and the normal direction, and a projection portion positioned between the first wall and the second wall in the orthogonal direction. The protruding portion is configured to protrude downstream in the extraction direction from the first wall and the second wall, so as not to interfere with the second detection portion when the extraction portion is in the first position. The sheet support device according to feature 9.

11. At least a portion of the second detection unit is located downstream of the first wall and the second wall in the pulling direction and within the space enclosed by the protruding portion when the pulling portion is in the first position. The sheet support device according to feature 10.

12. The aforementioned bulging portion is a roller for conveying the sheet. The sheet support device according to feature 1.

13. A sheet support device according to any one of claims 1 to 12, The system includes an image forming unit that forms an image on a sheet fed from the sheet support device. An image forming apparatus characterized by the following features.

Images