JP2018025685A - Sheet loading device and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet loading device that prevents the arrangement of sheets loaded on a sheet loading part from being disturbed and the sheets from being pushed out and dropped from the sheet loading part, and can ensure visibility of the sheets loaded on the sheet loading part, and an image forming apparatus.SOLUTION: A sheet ejection and loading part 200 being a sheet loading device comprises a sheet ejection tray 72 being a sheet loading part on which a sheet P being a sheet is loaded, and an inversion part 80 being a sheet inversion part that is provided above the sheet ejection tray 72 and inverts a conveyance direction of the sheet P fed thereto and feeds out the sheet P. The inversion part 80 includes a guide part consisting of an inversion tray 82 and an inversion extension tray 84 that guide an undersurface of the sheet P, where the inversion extension tray 84 being part thereof is formed of a transparent member.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sheet stacking apparatus and an image forming apparatus.

  2. Description of the Related Art Conventionally, there is known a sheet stacking apparatus including a sheet stacking unit on which sheets are stacked and a sheet reversing unit that is provided above the sheet stacking unit and reverses the transport direction of the fed sheet and sends it out.

  Patent Document 1 describes a sheet stacking apparatus that includes a reversing tray that guides the lower surface of a sheet that is reversed by a sheet reversing unit that is a sheet reversing unit.

  However, if the length of the reverse tray in the paper transport direction is shorter than the length of the paper in the paper transport direction, the leading end side of the paper to be reversed jumps out of the reverse tray and hangs down. When the leading end of the hanging paper comes into contact with the paper stacked on the paper output stacking unit, which is a sheet stacking unit, the alignment of the paper stacked on the paper output stacking unit is disturbed, or the paper is removed from the paper output stacking unit. There arises a problem that it is pushed out and dropped. On the other hand, if the leading end of the maximum length of paper that can be guided by the reverse tray is long enough not to hang down, the range in which the paper stacked on the paper discharge stacking unit is covered by the reverse tray becomes large. . For this reason, when using a relatively small size of paper, when the paper output stacking unit is viewed from above the reversing tray, the paper stacked on the paper output stacking unit is hidden by the reversing tray and visibility deteriorates. Problem arises.

  In order to solve the above-described problems, the present invention provides a sheet stacking unit on which sheets are stacked, a sheet reversing unit that is provided above the sheet stacking unit and that reverses the transport direction of the fed sheet and sends it out. In the sheet stacking apparatus, the sheet reversing unit includes a guide member that guides the lower surface of the sheet, and at least a part thereof is made of a transparent or translucent member.

  According to the present invention, it is possible to prevent the sheets stacked on the sheet stacking unit from being disturbed and to prevent the sheets from being pushed out and dropped from the sheet stacking unit. There is an excellent effect that visibility can be secured.

1 is a schematic configuration diagram of a printer according to an embodiment. FIG. FIG. 3 is an external perspective view of the printer in a state where a reverse extension tray and a reverse extension upper cover are removed from the apparatus main body. FIG. 4 is an explanatory diagram regarding the width of a sheet conveyance path in a reversing unit. FIG. 6 is an explanatory diagram regarding the height of a sheet reversing path in a reversing unit. The figure which shows the state which passed the paper more than predetermined length to the inversion part in the state without an inversion extension tray and an inversion extension upper cover in an inversion part. The figure which shows the state which passed the paper more than predetermined length to the inversion part in the state which has the inversion extension tray and the inversion extension upper cover in the inversion part. FIG. 3 is an external perspective view illustrating a state where discharged sheets are stacked on a discharge tray of the printer illustrated in FIG. 2. The schematic diagram of the attaching part of the reverse extension tray with respect to an apparatus main body, and the reverse extension upper cover. The figure which showed the cross-sectional shape of the engaging part of the reverse engagement member of a reverse extension tray, and the to-be-engaged member of an apparatus main body. The figure which showed the mounting method with respect to an apparatus main body of a reverse extension tray and a reverse extension upper cover. The figure which showed the 2nd engagement part with respect to an apparatus main body of a reverse extension tray and a reverse extension upper cover. FIG. 6 is an external perspective view of a modified printer. FIG. 14 is an external perspective view of the printer with the reverse extension upper cover removed from the state shown in FIG. 13. FIG. 6 is a schematic cross-sectional view of a reversing part and its vicinity in a printer of a modification example. FIG. 3 is an external perspective view of a printer of a reference configuration example.

  Hereinafter, an embodiment in which the present invention is applied to a printer which is an electrophotographic image forming apparatus will be described. First, a basic configuration of the printer according to the present embodiment will be described. FIG. 1 is a schematic configuration diagram illustrating a printer 100 that is an example of an image forming apparatus according to the present embodiment. The printer 100 includes a photoconductor 10 (Y, M, C, Bk) as four drum-shaped image carriers arranged in the apparatus main body 1. A yellow toner image, a magenta toner image, a cyan toner image, and a black toner image are formed on the four photoconductors 10 (Y, M, C, and Bk), respectively. An intermediate transfer belt 25, which is an intermediate transfer member, is disposed opposite to the four photosensitive members 10 (Y, M, C, Bk), and the four photosensitive members 10 (Y, M, C, Bk) are respectively intermediate. It is in contact with the surface of the transfer belt 25. The intermediate transfer belt 25 in the present embodiment is rotatably stretched by a driving roller 31, a driven roller 33, and a tension roller 34.

  The formation of the toner image on the photoreceptor 10 (Y, M, C, Bk) and the transfer of each toner image onto the intermediate transfer belt 25 are substantially performed on the photoreceptor 10 (Y, M, C, Bk). All are the same, only the color of each toner image formed is different. For this reason, the configuration and operation of forming a black toner image on the black photoconductor 10Bk out of the four photoconductors 10 (Y, M, C, Bk) and transferring the black toner image onto the intermediate transfer belt 25. explain.

  The black photoconductor 10Bk is rotationally driven in the clockwise direction in the drawing, and the surface of the black photoconductor 10Bk is uniformly charged to a negative polarity which is a predetermined polarity by the black charging device 8Bk. An electrostatic latent image corresponding to image information is formed by irradiating writing light from the exposure device 9 on the surface of the black photoreceptor 10Bk thus charged. With the rotation of the black photoconductor 10Bk, when the surface portion of the black photoconductor 10Bk on which the electrostatic latent image is formed passes through the developing area which is the portion facing the black developing device 7Bk, the black development is performed. The electrostatic latent image is developed by the black toner in the apparatus 7Bk. As a result, a visible image is formed as a black toner image. On the other hand, a black primary transfer roller 20Bk is disposed inside the intermediate transfer belt 25 at a position facing the black photoreceptor 10Bk with the intermediate transfer belt 25 interposed therebetween. The primary transfer roller for black 20Bk is in contact with the back surface of the intermediate transfer belt 25, so that an appropriate primary transfer nip is ensured between the black photoreceptor 10Bk and the intermediate transfer belt 25.

  A positive primary transfer voltage having a polarity opposite to the toner charging polarity of the black toner image formed on the surface of the black photoreceptor 10Bk is applied to the black primary transfer roller 20Bk. As a result, a transfer electric field is formed between the black photoconductor 10Bk and the intermediate transfer belt 25, and on the black photoconductor 10Bk on the intermediate transfer belt 25 driven to rotate in synchronization with the black photoconductor 10Bk. A black toner image is electrostatically transferred. The transfer residual toner adhering to the surface of the black photoconductor 10Bk after the black toner image is transferred onto the intermediate transfer belt 25 is removed by the black cleaning device 11Bk, and the surface of the black photoconductor 10Bk is cleaned.

  Similarly, a yellow toner image, a magenta toner image, and a cyan toner image are respectively formed on the other photoconductors 10 (Y, M, and C), and the toner images of the respective colors are intermediate images to which the black toner image is transferred. The images are transferred onto the transfer belt 25 in a superimposed manner.

  In the lower part of the apparatus main body 1, a paper feed cassette 400 that stores paper P and a paper feed device 40 that feeds paper P stored in the paper feed cassette 400 are arranged. Then, by rotating a paper supply roller 41 provided in the paper supply device 40, the uppermost paper P stored in the paper supply cassette 400 is sent out. Thus, the paper P sent out from the paper feed cassette 400 is sent to the registration roller pair 43 by the transport roller pair 42. Then, a pair of registration rollers 43 is formed between the portion of the intermediate transfer belt 25 wound around the drive roller 31 at a predetermined timing and the secondary transfer roller 32 of the secondary transfer device 30 disposed opposite thereto. Sent to the secondary transfer nip. At this time, by applying a predetermined secondary transfer voltage to the secondary transfer roller 32, a transfer electric field is formed between the intermediate transfer belt 25 and the secondary transfer roller 32, and the toner image on the intermediate transfer belt 25 is transferred. Secondary transfer is performed on the paper P.

  The sheet P on which the toner image has been transferred is conveyed toward the fixing device 50 disposed further above the apparatus than the secondary transfer nip. The fixing device 50 includes a fixing roller 51 and a heating roller 52 that are in contact with each other. When the sheet P passes through a fixing nip formed by the fixing roller 51 and the heating roller 52, heat and pressure are detected. Thus, the toner image on the paper P is fixed on the paper P.

  Thereafter, the paper P on which the toner image is fixed is discharged to a discharge path provided in the upper part of the apparatus main body 1. At the time of single-sided image formation in which an image is formed on only one side of the paper P, the paper conveyance path is switched by the switching claw 60 so that the paper P is sent to the paper discharge unit 70. The paper discharge unit 70 includes a paper discharge roller pair 71 and a paper discharge tray 72, and the paper P sent to the paper discharge unit 70 is discharged to the paper discharge tray 72 by the paper discharge roller pair 71. The sheets are sequentially stacked on the paper tray 72.

A reversing unit 80 including a reversing tray 82 and a reversing extension tray 84 is installed above the discharge tray 72. The reverse tray 82 and the reverse extension tray 84 guide the lower surface of the paper P that is reversed by the reverse roller pair 81.
The distance “b” from the reverse roller pair 81 to the end surface of the reverse extension tray 84 in the paper conveyance direction in the reversing unit 80 shown in FIG. 1 is longer than the paper conveyance direction length “a” of the paper feed cassette 400. Yes. Further, the end face of the reverse extension tray 84 coincides with the end face of the apparatus main body in the vertical direction, and the movement of the apparatus main body 1 in the case of an installation space where the end direction is narrow is unnecessary.

  The printer 100 forms a sheet discharge tray 72 that is a sheet stacking unit on which sheets P are stacked, and a reversal path (R1, R2) that is a sheet conveyance path to reverse the conveyance direction of the fed sheet P and send it out. And a reversing unit 80 which is a sheet reversing unit. The discharge tray 72 and the reversing unit 80 constitute a discharge stacking unit 200 that is a sheet stacking device.

A reverse upper cover 83 that covers the reverse tray 82 is provided above the reverse tray 82, and a reverse extension upper cover 85 that covers the reverse extension tray 84 is provided above the reverse extension tray 84. The reverse extension tray 84 and the reverse extension upper cover 85 are provided downstream of the reverse tray 82 and the reverse upper cover 83, respectively, in the sheet conveyance direction when the reverse tray enters.
In the printer 100, the reverse tray 82 and the reverse upper cover 83 are fixed to the apparatus main body 1, and the reverse extension tray 84 and the reverse extension upper cover 85 are arbitrarily detachable from the apparatus main body 1. Further, the reverse extension tray 84 and the reverse extension upper cover 85 are made of a transparent member.

FIG. 3 is an external perspective view of the printer 100 with the reverse extension tray 84 and the reverse extension upper cover 85 removed from the apparatus main body 1.
In the state shown in FIG. 3, the paper discharge unit right side plate 1 a that is parallel to the paper discharge direction in the paper discharge unit 70 of the apparatus main body 1 and is the right side plate with respect to the paper discharge direction is exposed. In the state shown in FIG. 3, the reverse tray downstream end surface 82a that is the downstream end surface of the reverse tray 82 in the paper transport direction, and the reverse upper cover downstream end surface 83a that is the downstream end surface of the reverse upper cover 83 in the paper transport direction. , Is exposed.
In the state shown in FIG. 2, the reverse extension tray 84 is in contact with two L-shaped surfaces formed by the paper discharge unit right side plate 1 a and the reverse tray downstream end surface 82 a, and the reverse extension upper cover 85 is disposed on the paper discharge unit right side plate. It is in contact with two L-shaped surfaces formed by 1a and the reverse upper cover downstream end surface 83a.

  As shown in FIG. 2, the upper surface of the reversing upper cover 83 and the reversing extension upper cover 85 of the reversing unit 80 is configured so as not to have a step difference from the other upper surface portions of the printer 100. The dimensions can be reduced, and the printer 100 can be reduced in size.

  FIG. 4 is an explanatory diagram of the width of the sheet reversing path in the reversing unit 80. “Α” in FIG. 4 indicates the paper conveyance direction, and “β” in FIG. 4 indicates the paper width direction. The same applies to “α” and “β” in other drawings to be described later. The sheet reversing path in the reversing unit 80 includes an upstream reversing path R1 formed by the reversing tray 82 and the reversing upper cover 83, and a downstream reversing path R2 formed by the reversing extension tray 84 and the reversing extension upper cover 85. It consists of and.

  The width “W1” in the sheet width direction of the upstream inversion path R1 is the distance between the inner wall surfaces in the sheet width direction of the reversing tray right side plate 821 and the reversing tray left side plate 822 provided on both sides of the reversing tray 82 in the sheet width direction. It is. This width “W1” is larger than the width “W0” of the maximum size paper P that can be used in the printer 100. Further, the width “W2” in the paper width direction of the downstream inversion path R2 is the width in the paper width direction of the additional tray right side plate 841 and the additional tray left side plate 842 provided on both sides of the reverse extension tray 84 in the paper width direction. This is the distance between the inner walls. This width “W2” is larger than the width “W1” of the upstream inversion path R1. As a result, the leading edge of the sheet P entering the downstream reversing path R2 from the upstream reversing path R1 is on the sheet conveying direction end surfaces (841a and 842a in FIG. 4) of the additional tray right side plate 841 and the additional tray left side plate 842. It is possible to suppress the occurrence of a conveyance failure by abutting.

  Not only in such a configuration, the width of the sheet reversing path gradually increases toward the downstream reversing path R2 at the connecting portion between the upstream reversing path R1 and the downstream reversing path R2. It may be configured.

  FIG. 5 is an explanatory diagram of the height of the sheet reversing path in the reversing unit 80. “Γ” in FIG. 5 indicates the height direction of the reversed portion. The same applies to “γ” in other drawings described later. In the reverse tray 82, the reverse tray facing surface 823 a of the reverse tray guide plate 823 faces the paper P. In the reverse upper cover 83, the reverse upper cover facing surface 833 a of the reverse upper cover upper plate 833 faces the paper P. The height “H1” of the upstream reversing path R1 that is the distance between the reversing tray facing surface 823a and the reversing upper cover facing surface 833a is the thickness “t” of the maximum thickness paper P that can be used in the printer 100. Bigger than.

  Further, in the reverse extension tray 84, the extension tray facing surface 843 a of the extension tray guide plate 843 faces the paper P. In the inverted extension upper cover 85, the extension cover facing surface 853 a of the extension cover upper plate 853 faces the paper P. The distance “H2” between the extension tray facing surface 843a and the extension cover facing surface 853a is larger than the distance “H1” of the upstream inversion path R1. Further, the extension tray facing surface 843a is positioned below the reversing tray facing surface 823a, and the extension cover facing surface 853a is positioned above the reversing upper cover facing surface 833a. As a result, the leading edge of the sheet P entering the downstream reversing path R2 from the upstream reversing path R1 is on the sheet conveying direction end surfaces (843b and 853b in FIG. 5) of the extension tray guide plate 843 and the extension cover upper plate 853. It is possible to suppress the occurrence of a conveyance failure by abutting.

  The reverse tray facing surface 823a, the reversing upper cover facing surface 833a, the extension tray facing surface 843a, and the extension cover facing surface 853a may be provided with uneven shapes. As the uneven shape, in the configuration shown in FIG. 5, the reverse tray rib 862 and the reverse upper cover rib 863 extending in the paper transport direction are provided on the reverse tray facing surface 823 a and the reverse upper cover facing surface 833 a respectively. A plurality are arranged side by side in the width direction. Further, a plurality of extension tray ribs 864 and extension cover ribs 865 extending in the paper transport direction are provided side by side in the paper width direction orthogonal to the paper transport direction on each of the extension tray facing surface 843a and the extension cover facing surface 853a. Thereby, the contact area of each of the reversing tray 82, the reversing upper cover 83, the reversing extension tray 84, and the reversing extension upper cover 85 with the paper P is smaller than when the ribs (862, 863, 864, 865) are not provided. it can. By reducing the contact area, it is possible to reduce the conveyance resistance and improve the sheet conveyance property.

  Thus, when the rib (862, 863, 864, 865) is provided, the setting is performed as follows. That is, the height “h1” of the upstream inversion path R1, which is the distance between the upper end of the inversion tray rib 862 and the lower end of the inversion upper cover rib 863, is the thickness “t” of the maximum thickness paper P that can be used in the printer 100. Larger than. Further, the height “h2” of the downstream inversion path R2 that is the distance between the upper end of the extension tray rib 864 and the lower end of the extension cover rib 865 is made larger than the height “h1” of the upstream inversion path R1. Then, the upper end of the extension tray rib 864 is positioned below the upper end of the reverse tray rib 862, and the lower end of the extension cover rib 865 is positioned higher than the lower end of the reverse upper cover rib 863. Accordingly, it is possible to suppress the occurrence of conveyance failure due to the leading edge of the sheet P entering the downstream reversing path R2 from the upstream reversing path R1 hitting the end surface of the extension tray rib 864 and the extension cover rib 865 in the sheet conveying direction.

  At the time of double-sided image formation, the paper conveyance path is switched by the switching claw 60 as shown in FIG. 1, and the single-sided printed paper P is the reverse tray 82, the reverse upper cover 83, the reverse extension tray 84, the reverse extension upper cover. It is conveyed to the reversing unit 80 formed by 85. On the other hand, the double-side printed paper P is conveyed to the paper discharge unit 70. The paper P transported to the reversing unit 80 is temporarily discharged onto the reversing tray 82 and the reversing extension tray 84 while the rear end is held between the reversing roller pair 81 serving as a reversing unit. Thereafter, the paper P is fed to the refeed path section 90 by controlling the drive motor that rotationally drives the reverse roller pair 81 to reversely rotate the reverse roller pair 81. Then, the paper P is sent to the transfer portion by the registration roller pair 43 sequentially through a plurality of transport roller pairs (91, 92, 93, 94), and is transferred from the intermediate transfer belt 25 to the back surface, which is the second surface of the paper P. The image is secondarily transferred.

  As described above, the reversing unit 80 can guide the lower surface of the sheet and cover the upper surface of the sheet over the entire length of the sheet even when the long sheet P such as A3 size or DLT size (double letter size) is reversed. Has a length. At the same time, the reverse extension tray 84 and the reverse extension upper cover 85 are removed from the apparatus main body 1, so that the length of the paper lower surface guide and the paper upper surface can be adjusted.

As shown in FIG. 3, the paper discharge unit right side plate 1a has a hook hole 87a for hooking the reverse extension tray 84 and the reverse extension upper cover 85, and a through hole 87b below the hook hole 87a.
FIG. 6 is a schematic cross-sectional view of the reversing unit 80 and the vicinity thereof in the printer 100 with the reversing extension tray 84 and the reversing extension upper cover 85 removed from the apparatus main body 1. As shown in FIG. 6, in the state where the reverse extension tray 84 and the reverse extension upper cover 85 are removed from the apparatus main body 1, if the reverse paper P <b> 2 is longer in the conveyance direction than the reverse tray 82 in the paper conveyance direction, The leading end side of the reversal paper P2 hangs down from the tray 82. For this reason, as shown in a region D surrounded by a broken line in FIG. 6, the leading end of the reversal paper P <b> 2 may be in contact with the discharged paper P <b> 1 on the paper discharge tray 72. In this state where the reversal paper P2 can contact the discharged paper P1, the paper alignment state of the discharged paper P1 is disturbed, or the discharged paper P1 is ejected from the paper discharge tray 72 and dropped. Paper misalignment will occur.

  FIG. 7 is a schematic cross-sectional view of the reversing unit 80 and its vicinity in the printer 100 with the reversal extension tray 84 and the reversal extension upper cover 85 attached to the apparatus main body 1. In the state shown in FIG. 7, the reverse tray 82 and the reverse extension tray 84 constitute a guide member that guides the lower surface of the sheet P that is a sheet. And the inversion extension tray 84 which is a part of guide member is comprised with a transparent member.

  FIG. 7 is a diagram illustrating a state in which a sheet P having a length that is longer than the reversing tray 82 in the sheet conveyance direction is passed through the reversing unit 80. As shown in FIG. 7, in the state where the reverse extension tray 84 and the reverse extension upper cover 85 are attached to the apparatus main body 1, the length of the reverse unit 80 in the sheet conveyance direction is extended as compared with FIG. 6. Therefore, even when reversing a long sheet P such as A3 size or DLT size, the bottom surface of the sheet can be guided by the reversing tray 82 and the reversing extension tray 84 over the entire length of the reversing sheet P2 in the sheet conveying direction. . Thereby, the leading end side of the reversal paper P2 does not hang down on the paper discharge tray 72, and the above-mentioned paper discharge alignment failure can be prevented.

  In FIG. 6, the leading end side of the reversing paper P <b> 2 is completely exposed from the reversing tray 82 and the reversing upper cover 83. Therefore, there is a possibility that the user pulls out the reversal paper P2 that is being reversed by the reversing unit 80. If the user pulls out the reversed paper P2 being reversed by the reversing unit 80, the printer 100 determines that a paper conveyance failure such as a paper jam has occurred in the conveyance path, and causes an unexpected jam. In addition, in the case of a high-productivity image forming apparatus having a large number of image forming units per unit time, the sheet conveyance speed during reversal is also increased. Therefore, there is a possibility that the user who sees the reversing paper P2 that is exposed by jumping out from the reversing tray 82 and the reversing upper cover 83 may feel uncomfortable.

  On the other hand, by attaching the reverse extension tray 84 and the reverse extension upper cover 85 to the apparatus main body 1 as shown in FIG. 7, the reverse paper P2 being reversed by the reversing unit 80 becomes the reverse extension tray 84 and the reverse extension upper cover. 85. Therefore, it becomes impossible for the user to pull out the paper that is being reversed by the reversing unit 80, and it is possible to prevent a jam that may occur when the reversed paper P2 is pulled out. Further, since the leading end side of the reversing paper P2 does not jump out of the reversing unit 80 and is exposed, it is possible to prevent the user from feeling uncomfortable when viewing the reversing paper P2 that pops out at high speed.

In the state of FIG. 6, the discharged paper P1 discharged to the paper discharge tray 72 can be visually recognized and taken out from any of the arrow A direction, the arrow B direction, and the arrow C direction in FIG. It is possible.
On the other hand, by attaching the reverse extension tray 84 and the reverse extension upper cover 85 to the apparatus main body 1, the reverse extension tray 84 and the reverse extension extend above the discharged paper P1 discharged to the discharge tray 72 as shown in FIG. The upper cover 85 covers the cover.

  FIG. 16 is an external perspective view of the printer 100 of the reference configuration example in which the reverse extension tray 84 and the reverse extension upper cover 85 are configured by non-transmissive members. As shown in FIG. 16, in the printer 100 of the reference configuration example, most of the paper discharge tray 72 is hidden by the reverse extension tray 84 and the reverse extension upper cover 85 when viewed obliquely from above. As described above, when the reverse extension tray 84 and the reverse extension upper cover 85 are attached, the discharged paper on the paper discharge tray 72 from the direction of the arrow A ′ in FIG. The visibility of P1 deteriorates, or the discharged paper P1 becomes difficult to take out.

On the other hand, as shown in FIG. 2, the printer 100 according to the present embodiment includes the reverse extension tray 84 and the reverse extension upper cover 85 made of transparent members.
As shown in FIG. 7, by attaching the reverse extension tray 84, the guide member has a length that does not hang down the leading end side of the paper P having a long paper conveyance direction length. Even with such a guide member, as shown in FIG. 2, the discharge tray 72 covered with the guide member can be visually recognized from the reverse extension tray 84 formed of a transparent or translucent member. it can.

FIG. 8 is an external perspective view showing a state where discharged paper P1 is stacked on the paper discharge tray 72 of the printer 100 shown in FIG. As shown in FIG. 8, in the printer 100 of the present embodiment, the visibility of the discharged paper P1 is ensured even when the reverse extension tray 84 and the reverse extension upper cover 85 cover the upper side of the discharged paper P1. Can do. Since the discharged paper P1 can be visually recognized, it is possible to ensure the take-out property of the discharged paper P1.
In the present embodiment, the reverse extension upper cover 85 that is a part of the guide member is formed of a transparent member. However, the entire guide member that guides the lower surface of the reverse paper P by the reverse portion 80 is transparent or semi-transparent. You may comprise with a member.

  As shown in FIG. 7, when the total length of the discharged paper P <b> 1 is short with respect to the reverse extension tray 84 that covers the upper side of the paper discharge tray 72, the paper from the arrow B ′ direction and the arrow C ′ direction in the figure. The take-out property is reduced.

  On the other hand, in the printer 100, when the relatively long paper P such as A3 size or DLT size (double letter size) is not passed, the reverse extension tray 84 and the reverse extension upper cover 85 are provided in the apparatus main body. 1 can be removed. As a result, the area of the paper discharge tray 72 covered by the reversing unit 80 is smaller than when the reverse extension tray 84 and the reverse extension upper cover 85 are attached to the apparatus main body 1. Therefore, it is possible to improve the take-out property of the discharged paper P1 stacked on the paper discharge tray 72 accordingly. Further, as described above, since the reverse extension tray 84 and the reverse extension upper cover 85 are transparent, the discharged paper P1 stacked on the paper discharge tray 72 can be visually recognized even when attached. However, the visibility can be improved by removing the reverse extension tray 84 and the reverse extension upper cover 85.

  The printer 100 includes a sensor member that detects the attachment state when the reverse extension tray 84 and the reverse extension upper cover 85 are attached to the apparatus main body 1. The sensor member detects attachment of the reverse extension tray 84 and the reverse extension upper cover 85, and the control unit of the apparatus main body 1 determines that A3 size paper or DLT size paper can be supplied from the paper supply cassette 400. And the control part of the apparatus main body 1 displays that it can operate on the display panel connected with the display panel of the apparatus main body 1 or the apparatus main body 1 by the communication means. When the reversal extension tray 84 and the reversal extension upper cover 85 are removed from the apparatus main body 1, control is performed so that paper cannot be fed from the paper feed cassette 400, and an inoperable display is displayed on the display device.

  FIG. 9 is a schematic view of a mounting portion of the reverse extension tray 84 and the reverse extension upper cover 85 with respect to the apparatus main body 1. The reverse extension tray 84 and the reverse extension upper cover 85 are integrally configured by being fixed to each other by fastening screws, and are provided with two reverse engagement members 86 provided on the reverse extension tray 84 in the sheet conveying direction. Yes. The reverse engagement member 86 may be provided on the reverse extension upper cover 85. In addition, the number of the reverse engagement members 86 is not limited to two, and may be three or more. When two or more reverse engagement members 86 are provided on the reverse extension tray 84 or the reverse extension upper cover 85. In this case, it is desirable that the plurality of reversing engagement members 86 be positioned on the same straight line in the sheet conveyance direction. On the sheet discharge unit right side plate 1 a of the apparatus main body 1, two engaged members 87 that are engaged with two reverse engagement members 86 provided on the reverse extension tray 84 are provided in the paper discharge direction. Then, the reverse extension tray 84 and the reverse extension upper cover 85 are mounted on the apparatus main body 1 by the engagement of the two reverse engagement members 86 and the two engaged members 87.

  Further, in the present embodiment, the thickness of one end side of the reverse extension upper cover 85 provided with the reverse engagement member 86 in the paper width direction is thicker than the thickness of the other end side in the paper width direction. Thereby, the rigidity at the one end side of the reverse extension upper cover 85 that becomes a root portion when the reverse extension tray 84 and the reverse extension upper cover 85 are attached to the apparatus main body 1 is higher than that at the other end side, and the reverse extension tray 84 and the reverse extension upper cover 85 can be prevented from being bent.

  FIG. 10 is a view showing a cross-sectional shape of the first engagement portion between the reverse engagement member 86 of the reverse extension tray 84 and the engaged member 87 of the apparatus main body 1. The reverse engagement member 86 has a hook-shaped portion 86a, and is screwed to the reverse-extension upper cover 85 in a state where the hook-shaped portion 86a protrudes from the side surface in the paper width direction of the reverse-extension upper cover 85. . In addition, a positioning convex portion 85a that protrudes from the side surface on the one end side in the paper width direction is provided below the hook-shaped portion 86a of the inverted extension upper cover 85. On the other hand, the engaged member 87 provided on the sheet discharge unit right side plate 1a of the apparatus main body 1 has a hook hole 87a for hooking the hook-shaped portion 86a, and a through hole into which the positioning convex portion 85a is inserted below. It has a hole 87b.

  FIG. 11 is a view showing a method of attaching the reverse extension tray 84 and the reverse extension upper cover 85 to the apparatus main body 1. As a method for mounting the reverse extension tray 84 and the reverse extension upper cover 85, the hook-shaped portion 86a of the reverse engagement member 86 is inserted into the hook hole 87a of the engaged member 87, and the reverse extension tray 84 and the reverse extension upper cover are left as they are. Rotate 85 downward. Then, the positioning convex portion 85 a of the reverse extension upper cover 85 is inserted into the through hole 87 b of the engaged member 87, and the hook-shaped portion of the reverse engagement member 86 is formed on the edge of the hook hole 87 a of the engaged member 87. Hook 86a. Thereby, the mounting of the reverse extension tray 84 and the reverse extension upper cover 85 to the apparatus main body 1 is completed. Therefore, the reverse extension tray 84 and the reverse extension upper cover 85 can be easily attached to the apparatus main body 1 without using a tool. By positioning the positioning convex portion 85a into the through hole 87b, the inverted extension upper cover 85 is positioned with respect to the apparatus main body 1. Further, in this configuration, the detachability is improved by mounting a sliding member 88 for improving the slipping when the positioning convex portion 85a is inserted into and removed from the through hole 87b so as to cover the edge of the through hole 87b. . As the material of the sliding member 88, for example, a resin such as polyacetal (POM) can be used.

  When removing the reverse extension tray 84 and the reverse extension upper cover 85 from the apparatus main body 1, the reverse operation at the time of mounting is performed. Accordingly, the reverse extension tray 84 and the reverse extension upper cover 85 can be easily detached from the apparatus main body 1 without using a tool. The storage place of the reverse extension tray 84 and the reverse extension upper cover 85 removed from the apparatus main body 1 is preferably as close to the printer 100 as possible. Therefore, for example, the outer cover of the apparatus main body 1 is provided with a hook hole for hooking the hook-shaped portion 86a as described above and a through hole into which the positioning convex portion 85a is inserted. Alternatively, the paper is stored in the paper feed cassette 400 that stores A3 size paper or DLT size paper among the plurality of paper feed cassettes 400. As a result, the reverse extension tray 84 and the reverse extension upper cover 85 removed from the apparatus main body 1 can be held on the exterior cover of the apparatus main body 1 or stored in the apparatus main body 1.

  FIG. 12 is a view showing a second engagement portion of the reverse extension tray 84 and the reverse extension upper cover 85 with respect to the apparatus main body 1. An insertion hole provided in the reverse tray 82 or the reverse upper cover 83 fixed to the apparatus body 1 at the opposite end of the reverse extension upper cover 85 in the paper width direction opposite to the side where the reverse engagement member 86 is located. A positioning member 89 that can be engaged and disengaged is provided. The positioning member 89 of the reverse extension upper cover 85 engages with the insertion hole provided on the surface (the reverse tray downstream end surface 82a or the reverse upper cover downstream end surface 83a) orthogonal to the sheet discharge unit right side plate 1a. A positioning member 89 may be provided at the opposite end of the reverse extension tray 84. The positioning member 89 provided on the reverse extension upper cover 85 is a movable member that can move forward and backward with respect to the insertion hole provided on the reverse tray 82 or the reverse upper cover 83, and is in the direction indicated by the arrow D in FIG. (Direction parallel to the direction) and the opposite direction. Further, the reverse extension upper cover 85 is provided with an operation window 85 b for allowing the user to pick a knob 89 a provided on the positioning member 89 and slide the positioning member 89. Then, the user picks the knob 89a from the operation window 85b, slides the positioning member 89, and moves the positioning member 89 forward and backward with respect to the insertion hole. The positioning member 89 inserted into the insertion hole is positioned in contact with at least the inner wall surface on the upper side of the insertion hole, and the position of the reverse extension upper cover 85 with respect to the reverse tray 82 or the reverse upper cover 83 is formed. ing.

[Modification]
FIG. 13 is an external perspective view of a modified printer 100, and FIG. 14 is an external perspective view of the printer 100 with the inverted extension upper cover 85 removed from the state shown in FIG. FIG. 15 is a schematic cross-sectional view of the reversing unit 80 and its vicinity in the printer 100 according to a modification.
In the printer 100 of the modified example, the reverse extension tray 84 is provided with notches (84a, 84b), and the end of the reverse extension tray 84 in the paper transport direction is covered with the reverse extension upper cover 85. This is different from the printer 100 of the embodiment described above. Other configurations are similar.

As shown in FIG. 13, in the printer 100 of the modified example, the extension cover rib 865 is provided on the extension cover facing surface 853 a that is the lower surface of the reverse extension upper cover 85, and in FIG. The extension cover rib 865 can be visually recognized. As shown in FIG. 14, extension tray ribs 864 are provided on the reverse tray facing surface 823 a that is the upper surface of the reverse extension tray 84.
In the printer 100 of the modified example, the reverse extension tray 84 is formed of a transparent member as in the printer 100 of the above-described embodiment. However, in FIGS. 13 and 14, the reverse extension tray 84 can be seen through. Parts are not shown for convenience.

  As illustrated in FIG. 14, the printer 100 according to the modification includes a left notch hole 84 a on the left side and a right notch hole 84 b on the right side with respect to the sheet conveyance direction when the reverse tray enters the reverse extension tray 84. The left cutout hole 84a and the right cutout hole 84b are provided on the downstream reversal path R2 that is an extended reversal path formed by the reversal extension tray 84 and the reversal extension upper cover 85, and on the outside of the apparatus above the discharge tray 72. Communicate with space. That is, the left notch hole 84a and the right notch hole 84b have a notch shape in which both ends of the rectangular sheet width direction are notched so as to communicate from the extension tray facing surface 843a of the reverse extension tray 84 to the outside of the apparatus.

In the printer 100 of the reference configuration example shown in FIG. 16, the visibility / removability of jammed paper when a paper jam occurs inside the downstream reversing path R2 formed by the reversing extension tray 84 and the reversing extension upper cover 85. There is a problem that decreases.
On the other hand, the printer 100 according to the above-described embodiment and this modification can ensure the visibility of the jammed paper in the downstream inversion path R2 by configuring the inversion extension upper cover 85 with a transparent member. .
Furthermore, in the printer 100 of this modification, it is possible to remove the jammed paper remaining in the downstream reversing path R2 by providing a cutout in the reverse extension tray 84, and to ensure the removability of the jammed paper. Can do.

13 and 15 show a state in which a jam has occurred in the downstream inversion path R2 in a state where the inversion extension tray 84 and the inversion extension upper cover 85 are attached to the printer 100. FIG. Since the reverse extension upper cover 85 is made of a transparent member, the jammed paper P2a in the downstream reverse path R2 can be visually recognized.
Further, since the notch holes (84a, 84b) are provided in the reverse extension tray 84, the jammed paper P2a can be pulled out from the notch holes (84a, 84b) and removed.

As shown in FIG. 14, the cutout holes (84 a, 84 b) are provided at both ends of the reverse extension tray 84 in the sheet width direction perpendicular to the sheet conveyance direction. If the jammed paper P2a is to be pulled out from the notch holes (84a, 84b) provided at the end in the paper width direction, the jammed paper P2a may be twisted and the shape may be crumbled or broken in the middle. There is.
As a configuration for suppressing such inconvenience, an end portion of the reverse extension tray 84 in the paper transport direction is not covered with the reverse extension upper cover 85, and an opening that communicates the downstream inversion path R2 and the outside of the apparatus to this end portion. It is good also as a structure which provides a part. In this configuration, the jammed paper P2a can be pulled out along the transport direction by grasping the jammed paper P2a from the notch holes (84a, 84b) at both ends in the paper width direction and pulling the jammed paper P2a toward the opening. The occurrence of the above-described problems can be suppressed.

  In the printer 100 of the above-described embodiment, at least one of the reverse upper cover 83 and the reverse extension upper cover 85 is configured to be openable and closable, and the reverse upper cover 83 or the reverse extension upper cover 85 that can be opened and closed is opened when a jam occurs. This makes it possible to remove jammed paper. On the other hand, in the printer 100 of the modified example, by providing the notch holes (84a, 84b) in the reverse extension tray 84, the downstream reverse path R2 without opening or closing the reverse upper cover 83 or the reverse extension upper cover 85. It becomes possible to remove the jammed paper remaining inside. Thereby, the removal property of jam paper is securable.

  What was demonstrated above is an example, and there exists an effect peculiar for every following aspect.

(Aspect A)
A sheet stacking unit such as a paper discharge tray 72 on which sheets of paper P or the like are stacked, and a sheet reversing unit such as a reversing unit 80 provided above the sheet stacking unit and reversing the transport direction of the fed sheet , The sheet reversing unit guides the lower surface of the sheet, and at least a part of the reversal extension tray 84 or the like is a reversing tray 82 made of a transparent or translucent member. And a guide member such as a reverse extension tray 84.
According to this, as described in the above embodiment, even if the guide member has a length in which the leading end side of the sheet having a long sheet conveyance direction length does not hang down, from the portion formed of a transparent or translucent member. The sheet stacking portion covered with the guide member can be visually recognized. By setting the length of the guide member so that the leading edge side of the sheet does not hang down, it is possible to prevent the sheet guiding the lower surface of the sheet by the guide member from coming into contact with the sheet stacked on the sheet stacking unit. It becomes possible. Therefore, it is possible to suppress the alignment of the sheets stacked on the sheet stacking unit from being disturbed by the sheet fed to the sheet reversing unit, or the sheet from being pushed out and falling. In addition, since the sheet stacking portion covered by the guide member can be visually recognized, the visibility of the sheets stacked on the sheet stacking portion can be ensured.

(Aspect B)
In the aspect A, the guide member includes a first guide member such as a reversing tray 82 that guides the sheet lower surface on the upstream side in the direction in which the sheet P or the like is fed into the sheet reversing unit such as the reversing unit 80, and the first guide member And a second guide member such as a reverse extension tray 84 for guiding the lower surface of the sheet on the downstream side, and at least a part of the second guide member is made of a transparent or translucent member.
According to this, as described in the above embodiment, when using a sheet having a length in the sheet conveyance direction longer than that of the first guide member, the lower surface of the long sheet fed into the sheet reversing portion is the first guide member. And the second guide member. As a result, compared to a configuration in which the length of the guide member in the sheet conveyance direction is only the length of the first guide member, the leading end side of the sheet fed to the sheet reversing unit hangs down and comes into contact with the sheets stacked on the sheet stacking unit. It becomes possible to suppress this. Therefore, it is possible to prevent the sheets fed to the sheet reversing unit from being disturbed or pushed out and dropped due to the alignment of the sheets stacked on the sheet stacking unit. In addition, since the sheet stacking portion covered by the second guide member can be visually recognized by the portion formed of the transparent or translucent member in the second guide member, the visibility of the sheets stacked on the sheet stacking portion is visible. Can be secured.

(Aspect C)
In the aspect B, the second guide member such as the reverse extension tray 84 can be attached to and detached from the apparatus main body such as the apparatus main body 1.
According to this, as described in the above embodiment, when a sheet such as a sheet P having a shorter sheet conveyance direction length such as the sheet conveyance direction than the first guide member such as the reversing tray 82 is used, Remove the guide member. As a result, since the area covered by the sheet stacking portion such as the discharge tray 72 by the second guide member is smaller than when the second guide member is attached to the apparatus main body, the sheets stacked on the sheet stacking portion are visually recognized. Property and take-out property can be improved.

(Aspect D)
In the aspect B or C, the surface (the reverse tray facing surface 823a or the extension tray facing surface) facing the sheet such as the sheet P in at least one of the first guide member such as the reverse tray 82 or the second guide member such as the reverse extension tray 84. 843a and the like) is provided with an uneven shape.
According to this, as described in the above embodiment, the sheet conveyance property can be improved.

(Aspect E)
In any of the aspects B to D, the sheet reversing unit such as the reversing unit 80 includes the first guide cover member such as the reversing upper cover 83 that covers the first guide member such as the reversing tray 82 and the first reversing extension tray 84 and the like. A second guide cover member such as a reverse extension upper cover 85 that covers the two guide members, and at least a part of the second guide cover member is made of a transparent or translucent member.
According to this, as described in the above-described embodiment, it is possible to prevent the user from pulling out the sheet such as the paper P being reversed. In addition, it is possible to prevent the user from feeling uncomfortable when viewing the popping sheet. Furthermore, since the sheet guide part covered with the second guide member and the second guide cover member can be visually recognized by the portion formed of the transparent or translucent member in the second guide cover member, The visibility of the stacked sheets can be ensured.

(Aspect F)
In aspect E, the left notch hole 84a, the right notch hole 84b, and the like that communicate with the sheet guide sheet such as the sheet P in the second guide member such as the reverse extension tray 84 (extension tray facing surface 843a and the like) communicate with the outside of the apparatus. It has a notch shape.
According to this, as described in the modification, the jam remaining in the extended reversing path such as the downstream reversing path R2 formed by the second guide member and the first guide cover member such as the reversing upper cover 83. The removability of sheets such as paper P2a can be ensured.

(Aspect G)
In the aspect E or F, the second guide cover member such as the inverted upper cover 83 can be attached to and detached from the apparatus main body such as the apparatus main body 1.
According to this, as described in the above embodiment, when a sheet such as a sheet P having a shorter sheet conveyance direction length such as the sheet conveyance direction than the first guide member such as the reversing tray 82 is used, Remove the guide cover member. As a result, the sheet stacked on the sheet stacking portion is smaller than the area where the sheet stacking portion such as the discharge tray 72 is covered by the second guide cover member as compared with the case where the second guide cover member is attached to the apparatus main body. Visibility and take-out property can be improved.

(Aspect H)
In any of the aspects E to G, a surface (inverted upper cover) of at least one of the first guide cover member such as the inverted upper cover 83 or the second guide cover member such as the inverted extended upper cover 85 facing the sheet such as the sheet P. An uneven shape is provided on the facing surface 833a or the extension cover facing surface 853a.
According to this, as described in the above embodiment, the sheet conveyance property can be improved.

(Aspect I)
In the aspect D or H, the uneven shape is a sheet width direction or the like in which the ribs such as the reverse tray rib 862, the reverse upper cover rib 863, the extension tray rib 864, and the extension cover rib 865 extending in the sheet transport direction such as the sheet transport direction are orthogonal to the sheet transport direction. Are arranged side by side in the sheet width direction.
According to this, as described in the above embodiment, the sheet conveyance property can be improved.

(Aspect J)
A printer 100 having an image forming unit such as the apparatus main body 1 that forms an image on a sheet such as paper P, and a sheet stacking unit such as a discharge tray 72 that stacks a sheet on which an image is formed by the image forming unit; In the image forming apparatus, the sheet stacking device according to any one of modes A to I is used as the sheet stacking unit.
According to this, as described in the above-described embodiment, the alignment of the sheets after image formation stacked on the sheet stacking unit is prevented from being disturbed or pushed and dropped, and the sheet stacking unit is stacked on the sheet stacking unit. This ensures the visibility of the sheet.

DESCRIPTION OF SYMBOLS 1 Apparatus main body 1a Paper discharge part right side board 7Bk Black developing device 8Bk Black charging device 9 Exposure device 10Bk Black photoconductor 10 Photoconductor 11Bk Black cleaning device 20Bk Black primary transfer roller 25 Intermediate transfer belt 30 Secondary transfer device 31 Driving roller 32 Secondary transfer roller 33 Driven roller 34 Tension roller 40 Paper feed device 41 Paper feed roller 42 Carrying roller pair 43 Registration roller pair 50 Fixing device 51 Fixing roller 52 Heating roller 60 Switching claw 70 Paper discharge unit 71 Paper discharge roller Pair 72 Discharge tray 80 Reverse section 81 Reverse roller pair 82 Reverse tray 82a Reverse tray downstream end face 83 Reverse upper cover 83a Reverse upper cover downstream end face 84 Reverse extension tray 84a Left notch hole 84b Right notch hole 85 Reverse extension upper Cover 85a Convex part 85 Operation window 86 Reverse engagement member 86a Hook-shaped portion 87 Engaged member 87a Hook hole 87b Through hole 88 Sliding member 89a Picking portion 89 Positioning member 90 Refeed path portion 100 Printer 200 Discharge stacking portion 400 Feed cassette 821 Reverse tray right plate 822 Reverse tray left plate 823 Reverse tray guide plate 823a Reverse tray facing surface 833 Reverse upper cover upper plate 833a Reverse upper cover facing surface 841 Additional tray right plate 842 Additional tray left plate 843 Extension tray guide plate 843a Surface 853 Extension cover upper plate 853a Extension cover facing surface 862 Reverse tray rib 863 Reverse upper cover rib 864 Extension tray rib 865 Extension cover rib P Paper P1 Ejected paper P2 Reverse paper P2a Jam paper R1 Upstream reverse path R2 Downstream reverse path

Japanese Patent No. 4890896

Claims (10)

A sheet stacking unit on which sheets are stacked;
A sheet stacking device provided above the sheet stacking unit, and having a sheet reversing unit that reverses the transport direction of the fed sheet and sends it out,
The sheet reversing unit includes a guide member that guides the lower surface of the sheet and includes a guide member that is at least partially made of a transparent or translucent member. The sheet stacking apparatus according to claim 1, wherein
The guide member includes a first guide member that guides the lower surface of the sheet on the upstream side in a direction in which the sheet is fed into the sheet reversing portion, and a second guide member that guides the lower surface of the sheet on the downstream side of the first guide member. Have
At least a part of the second guide member is made of a transparent or translucent member. The sheet stacking apparatus according to claim 2,
2. The sheet stacking apparatus according to claim 1, wherein the second guide member is detachable from the apparatus main body. The sheet stacking apparatus according to claim 2 or 3,
A sheet stacking apparatus, wherein an uneven shape is provided on a surface of at least one of the first guide member and the second guide member facing the sheet. The sheet stacking apparatus according to any one of claims 2 to 4,
The sheet reversing portion includes a first guide cover member that covers the first guide member;
A second guide cover member covering the second guide member;
At least a part of the second guide cover member is formed of a transparent or translucent member. The sheet stacking apparatus according to claim 5.
A sheet stacking apparatus having a notch shape that leads to the outside of the apparatus from a surface facing the sheet in the second guide member. The sheet stacking apparatus according to claim 5 or 6,
The sheet stacking apparatus, wherein the second guide cover member is detachable from the apparatus main body. The sheet stacking apparatus according to any one of claims 5 to 7,
A sheet stacking apparatus, wherein an uneven shape is provided on a surface of at least one of the first guide cover member and the second guide cover member facing the sheet. The sheet stacking apparatus according to claim 4 or 8,
The uneven shape is configured by arranging a plurality of ribs extending in the sheet conveying direction in a sheet width direction orthogonal to the sheet conveying direction. Image forming means for forming an image on a sheet;
In an image forming apparatus comprising a sheet stacking unit that stacks sheets on which images are formed by the image forming unit,
An image forming apparatus using the sheet stacking apparatus according to claim 1 as the sheet stacking unit.

Images