JP4958467B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus, such as a copying machine, a printer, and a facsimile, having a function of forming an image on a recording medium (recording material, transfer material) such as a sheet.

  FIG. 6 is a schematic sectional view of a conventional typical image forming apparatus.

  The image forming apparatus includes a sheet feeding apparatus including a feeding tray 101, a sheet stacking table 102, and a feeding roller 103. The sheets S stacked on the sheet stacking table 102 in the feeding tray 101 are picked up one by one from the uppermost sheet by the feeding roller 103 and sent to the registration unit by the conveying roller 104 and the conveying roller 105. The sheet is fed to the image forming unit after the conveyance direction is aligned by a registration unit including a registration roller 106 and a registration roller 107.

  The image forming unit includes a toner cartridge including a photosensitive drum 108, a charger that charges the photosensitive drum 108, a developing unit that develops the latent image on the photosensitive drum 108 with toner, a cleaner that removes and stores residual toner on the photosensitive drum 108, and the like. 109 is configured as a unit.

  The laser scanner unit 110 is constituted by unitizing a polyhedral mirror 111, a polyhedral mirror rotating motor, a laser unit, and the like.

  A laser beam L based on image information is irradiated from the laser scanner unit 110 and exposed on the photosensitive drum 108, and a latent image is formed by an electrophotographic method. The latent image is developed with toner by the developing means, and the developed toner image is transferred onto the sheet conveyed from the photosensitive drum 108 by the transfer roller 112. The sheet onto which the toner image has been transferred is conveyed to a fixing means comprising a heating unit 113 and a pressure roller 114, where the transferred toner image is heated and fixed.

  The sheet on which the toner image is heat-fixed is discharged to a discharge destination (face-up (FU) tray 118 or face-down (FD) tray 119) selected by the user.

  FIG. 6 is a diagram illustrating a case where the FU tray 118 is closed and the FD tray 119 is selected as the discharge port. In the case shown in FIG. 6, the sheet on which the toner image is heated and fixed by the fixing unit is discharged to the FD tray 119 by a discharge unit including the FU discharge roller 115, the intermediate discharge roller 116, the FD discharge roller 117, and the like.

  FIG. 7 is a diagram illustrating a case where the FU tray 118 is opened and the FU tray 118 is selected as a discharge destination. In the case shown in FIG. 7, the sheet on which the toner image is heated and fixed by the fixing unit is discharged to the FU tray 118 by the FU discharge roller 115.

FIG. 8 shows a jam processing method when a sheet is jammed in the fixing unit. In the case shown in FIG. 8, the FU tray 118 has two open positions. At the position indicated by 118a in FIG. 8, the sheet conveyance path to the FD tray 119 is opened to remove the sheet from the FU tray 118. Is supposed to lead to. On the other hand, at a position indicated by 118b in FIG. 8, the FU tray 118 releases the fixing nip via a link lever (not shown) so that the jammed sheet can be easily pulled out. As a document disclosing related conventional examples, there is Patent Document 1.
JP 2002-296948 A

  However, in the conventional image forming apparatus as described above, there are concerns about the following problems.

  In the conventional apparatus, the FU tray has two open positions: an open position for FU discharge and an open position for jam processing. The sheet conveyance path of the fixing discharge section is already opened at the open position for FU discharge. For this reason, there is a concern that the user may not notice that there is an open position at the time of jam processing.

  If the user does not notice that there is an open position at the time of jam processing, the user attempts jam processing at the open position at the time of FU discharge, so the fixing nip cannot be released, and jam processing becomes difficult.

  The present invention has been made in view of the circumstances as described above, and it is an object of the present invention to facilitate jam processing at a fixing and discharging unit and improve usability (convenience).

In order to achieve the above object, according to the present invention, a sheet on which an unfixed toner image is formed is nipped and conveyed by a fixing nip configured to be pressed against each other by a heating member and a pressure member. Fixing means for fixing an unfixed toner image on the sheet;
A first tray for face-down discharge from which the sheet that has passed through the fixing nip is discharged;
A second tray for face-up discharge that is openable and closable for discharging the sheet that has passed through the fixing nip;
Have
When the second tray is closed, the sheet passing through the fixing nip is discharged to the first tray, and when the second tray is opened, the sheet passing through the fixing nip is discharged to the second tray. In the image forming apparatus to
An opening / closing member provided to be openable / closable with respect to the apparatus main body on the inner side of the apparatus main body than the second tray;
A release mechanism that releases the contact pressure of the fixing nip in conjunction with the opening and closing operation of the opening and closing member;
With
The opening / closing shafts of the opening / closing member and the second tray are parallel to each other, and the opening / closing member is provided so that an operator can operate even when the second tray and the opening / closing member are closed. When the opening / closing member is opened with the opening / closing member closed, the second tray is also integrally opened, and the contact pressure of the fixing nip is released.

  According to the present invention, it is possible to facilitate jam processing at the fixing and discharging unit and improve usability (convenience).

  The best mode for carrying out the present invention will be exemplarily described in detail below with reference to the drawings. However, the dimensions, materials, shapes, and relative arrangements of the components described in this embodiment should be appropriately changed according to the configuration of the apparatus to which the invention is applied and various conditions. It is not intended to limit the scope to the following embodiments.

  1 to 3 are schematic sectional views showing an image forming apparatus according to an embodiment of the present invention.

  The image forming apparatus according to the present embodiment includes a sheet feeding device including a feeding tray 1, a sheet stacking table 2, and a feeding roller 3.

The sheets S stacked on the sheet stacking table 2 in the feeding tray 1 are picked up one by one from the uppermost sheet by the feeding roller 3 and sent to the registration unit by the conveying roller 4 and the conveying roller 5. The sheet S is fed to the image forming unit after the conveyance direction is aligned by a registration unit including the registration rollers 6 and the registration rollers 7.

  The image forming unit includes a photosensitive drum 8, a charger for charging the photosensitive drum 8, a developing unit for developing the latent image on the photosensitive drum 8 with toner, a cleaner for removing residual toner on the photosensitive drum 8, and storing it. The toner cartridge 9 is configured as a unit.

  The laser scanner unit 10 is configured by unitizing a polyhedral mirror 11, a polyhedral mirror rotating motor, a laser unit, and the like.

  A laser beam L based on image information is irradiated from the laser scanner unit 10 and exposed on the photosensitive drum 8, and a latent image is formed by an electrophotographic method. The latent image is developed with toner as a developer by a developing unit, and the developed toner image is transferred onto the sheet S conveyed from the photosensitive drum 8 by the transfer roller 12. The sheet S on which the toner image has been transferred is conveyed to a fixing means comprising a heating unit 13 as a heating member and a pressure roller 14 as a pressure member, and the unfixed toner image transferred here is heated and fixed.

  The sheet S on which the toner image is heat-fixed is a discharge destination selected by the user, that is, a face-down (FD) discharge unit as a first discharge unit or a face-up (FU) discharge unit as a second discharge unit. To be discharged. The FD discharge unit is a face-down discharge unit that discharges the image forming surface of the sheet that has passed through the fixing nip N downward, and the FU discharge unit is configured to discharge the image forming surface of the sheet that has passed through the fixing nip N. It is a discharge part for face-up discharge that discharges upward. Here, the FU discharge unit is configured by the FU tray 21, and the FD discharge unit is configured by the FD tray 19.

  The characteristic configuration of this embodiment will be described below.

  In the present embodiment, the tray of the FU discharge unit is configured to have a double stack of a FU tray 21 as a first opening / closing member and a rear cover 22 as a second opening / closing member, and can be opened and closed with respect to the apparatus main body. Is provided.

  The rear cover 22 forms a part of a sheet conveyance path that leads from the fixing nip N configured to be in pressure contact with each other by the heating unit 13 and the pressure roller 14 to the FD tray 19. On the other hand, the FU tray 21 is disposed outside the rear cover 22. That is, the rear cover 22 is provided on the inner side of the apparatus body from the FU tray 21. The FU tray 21 has a function of guiding the sheet S that has passed through the fixing nip N to the FD tray 19 at the closed position and guiding the sheet S to the FU discharge unit at the open position, and discharging and stacking the sheets S.

  Here, FIG. 1 shows a case where the FU tray 21 is closed and the FD tray 19 is selected as the discharge port. The sheet S on which the toner image is heated and fixed by the fixing unit is discharged to the FD tray 19 by a discharge unit including the FU discharge roller 15, the intermediate discharge roller 16, the FD discharge roller 17, and the like.

  FIG. 2 shows a case where only the FU tray 21 is opened and the FU tray 21 is selected as the discharge destination. The sheet on which the toner image is heated and fixed by the fixing unit is FU discharged by the FU discharge roller 15. It is discharged to the tray 21. FIG. 3 shows a jam processing method when the sheet S is jammed in the fixing unit.

When performing FD discharge, the FU tray 21 is closed as shown in FIG. 1, and when performing FU discharge, only the FU tray 21 is opened at a position indicated by reference numeral 21a as shown in FIG.

  When the sheet S is jammed in the fixing and discharging unit, as shown in FIG. 3, the FU tray 21 and the rear cover 22 are simultaneously opened to open the sheet conveyance path. As a result, the fixing nip N is released as will be described later.

  4 and 5 are diagrams for explaining the release of the fixing nip N of the image forming apparatus according to the present embodiment. FIG. 4 shows a state before release, and FIG. 5 shows the release state.

  In a state before the fixing nip N is released, as shown in FIG. 4, the fixing pressure plate 25 urged by a spring 26 as urging means presses the heating unit 13, so that a predetermined nip N is provided in the fixing nip N. Contact pressure is acting.

  During the jam processing, the FU tray 21 and the rear cover 22 are simultaneously opened to open the sheet conveyance path.

  The rear cover 22 is provided with a cam 23 as a cam portion (rotating portion, interlocking portion). When the rear cover 22 is opened, the cam 23 engages with a link lever (release member, interlocking member) 24 to link lever. 24 is configured to push up. The link lever 24 lifts the fixing pressure plate 25 against the urging force of the spring 26, so that the contact pressure of the fixing nip N is released. Here, the link lever 24 and the fixing pressure plate 25 constitute a release mechanism according to the present invention. The cam 23 constitutes interlocking means according to the present invention.

  As described above, in the present embodiment, the sheet that has passed through the fixing nip N is guided to the FD discharge unit in the closed position, and the FU tray 21 that guides the sheet to the FU discharge unit in the open position. A rear cover 22 is provided on the inside of the main body in a stack of two sheets. The rear cover 22 forms a part of the sheet conveyance path from the fixing nip N to the FD discharge unit. The opening / closing of the rear cover 22 and the release mechanism of the fixing nip N are interlocked so that the contact pressure of the fixing nip N can be released simultaneously with opening the rear cover 22 and opening the sheet conveyance path.

  As described above, since the contact pressure of the fixing nip N is released by opening the sheet conveyance path, it is possible to intuitively release the fixing nip during the jam processing, and it is possible to improve the jam processing performance. Become. Therefore, it is possible to facilitate jam processing at the fixing and discharging unit, and to improve usability (convenience).

1 is a schematic cross-sectional view of an image forming apparatus according to an embodiment of the present invention. 1 is a schematic cross-sectional view of an image forming apparatus according to an embodiment of the present invention. 1 is a schematic cross-sectional view of an image forming apparatus according to an embodiment of the present invention. FIG. 4 is a view for explaining release of the fixing nip of the image forming apparatus according to the embodiment of the present invention. FIG. 4 is a view for explaining release of the fixing nip of the image forming apparatus according to the embodiment of the present invention. FIG. 10 is a schematic cross-sectional view illustrating an example of a conventional image forming apparatus. FIG. 10 is a schematic cross-sectional view illustrating an example of a conventional image forming apparatus. FIG. 10 is a schematic cross-sectional view illustrating an example of a conventional image forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 13 Heating unit 14 Pressure roller 15 FU discharge roller 19 FD tray 21 FU tray 22 Rear cover 23 Cam 24 Link lever 25 Fixing pressure plate 26 Spring

Claims (1)

Fixing means for fixing the unfixed toner image on the sheet by nipping and conveying the sheet on which the unfixed toner image is formed in a fixing nip configured to be in pressure contact with each other by a heating member and a pressure member; ,
A first tray for face-down discharge from which the sheet that has passed through the fixing nip is discharged;
A second tray for face-up discharge that is openable and closable for discharging the sheet that has passed through the fixing nip;
Have
When the second tray is closed, the sheet passing through the fixing nip is discharged to the first tray, and when the second tray is opened, the sheet passing through the fixing nip is discharged to the second tray. In the image forming apparatus to
An opening / closing member provided to be openable / closable with respect to the apparatus main body on the inner side of the apparatus main body than the second tray;
A release mechanism that releases the contact pressure of the fixing nip in conjunction with the opening and closing operation of the opening and closing member;
With
The opening / closing shafts of the opening / closing member and the second tray are parallel to each other, and the opening / closing member is provided so that an operator can operate even when the second tray and the opening / closing member are closed. 2. An image forming apparatus according to claim 1, wherein when the opening / closing member is opened with the opening / closing member closed, the second tray is also integrally opened to release the contact pressure of the fixing nip.

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