JPH11228034A - Image forming device - Google Patents

Abstract

(57) [Problem] To provide an image forming apparatus capable of minimizing a space for taking out a sheet and realizing workability of taking out the sheet and downsizing of the apparatus. A paper feeding path for guiding a sheet conveyed along a return path to an image forming means (3) again along a paper path at a junction of a return path (22) and a paper path (19). (32) and a paper path switching member (29) supported so as to be switchable between a paper path (33) that sends out the paper conveyed in the return path in a substantially horizontal direction, and conveys the paper along the paper discharge path. An opening / closing cover (17) for opening the paper feed path was provided at a portion facing the leading end of the sheet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus capable of recording and forming an image on both sides of a sheet.

[0002]

2. Description of the Related Art In an image forming apparatus capable of forming images on both sides of a sheet, an image forming means for recording and forming an image on a conveyed sheet and a discharging unit for accommodating the sheet after image recording are provided. A main transport path (paper feed path) for communicating the paper section,
A retraction path provided by branching from a paper feed path on the downstream side in the sheet conveyance direction with respect to the image forming means, and a branch from the middle of the retraction path, and the end thereof is located on the upstream side in the sheet conveyance direction with respect to the image formation means. 2. Description of the Related Art An image forming apparatus including a return path joined to a paper feeding path is known.

In the case of performing double-sided printing in the image forming apparatus having the above-described configuration, a sheet on which an image has been formed on the first surface by the image forming means is drawn into the drawing path, and the trailing end of the sheet is a branch point between the drawing path and the return path. When the sheet is passed through the paper path, the sheet drawn into the drawing path is sent out to the return path so that the sheet is turned upside down. The sheet is sent again to the image forming means to form an image on the second surface of the sheet.

Conventionally, in this type of image forming apparatus, if it is necessary to remove the paper stagnant in the paper feed path, the drawing path and the return path due to a paper jam or the like for some reason, the return path and the paper feed path have to be removed. As shown in FIG. 4, for the sheet stagnated near the confluence point of FIG. 4, the open / close cover 40 is opened from the normal (FIG. 4A) state, and the sheet guide member 41 is moved to such an extent that the sheet feeding path is slightly widened. As shown in FIG. 4B, the transport roller 42 provided on the return path is rotated in a state where the paper feed path is widened, and the paper P is discharged.

[0005]

However, in the case of the above construction, the paper is discharged obliquely upward, so that a space for taking out the paper is required at the upper part in the discharge direction, and the apparatus becomes large. Had occurred.

SUMMARY OF THE INVENTION An object of the present invention is to make it possible to discharge a sheet stagnating near a junction of a return path and a paper feed path almost straight from the return path, to minimize the space for taking out the sheet, and to take out the sheet. An object of the present invention is to provide an image forming apparatus capable of realizing the workability of the above and the downsizing of the apparatus.

[0007]

The object of the present invention is to provide a paper feeding unit,
An image forming means for recording and forming an image on the conveyed paper and a paper feed path for communicating a paper discharge unit for accommodating the image-recorded paper; and a paper feed path on the downstream side in the paper conveying direction with respect to the image forming means. An image recording apparatus having a branch path provided therein and a return path branching from the middle of the branch path and joining the terminal end thereof to a paper feed path on the upstream side in the sheet conveyance direction with respect to the image forming means. A sheet feeding path for guiding the paper conveyed along the return path to the image forming unit again along the paper feed path at a junction of the return path and the paper feed path; A paper path switching member supported so as to be switchable to a discharge path for sending the conveyed paper in a substantially horizontal direction is provided, and the paper path switching member is provided at a portion facing the leading end of the paper conveyed along the discharge path. Equipped with an open / close cover to open the paper path It is achieved by Rukoto.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1, 2 and 3. FIG. First, the overall configuration of the image forming apparatus will be described with reference to FIG. Image forming apparatus A
Is constructed from the paper feed section a _1, the image forming unit a ₂ and the vertical transport unit a _3. Here, the sheet feeding unit a ₁ , the image forming unit a _2, and the vertical conveying unit a ₃ are not necessarily formed separately, but may be integrally formed.

The paper supply section a ₁ includes a paper storage section 1 for storing and storing the paper P, and a paper supply section 2 for feeding out the paper P stored in the paper storage section 1 one by one. Paper feeding means 2
Is composed of a pick roller 2a, a feed roller 2b, and a retard roller 2c.

[0010] Above the sheet feeding portion a _1, the image forming unit a ₂ having an image forming means 3 an image recorded formed on the sheet P fed by the paper feeding means 2 is arranged. The image forming unit 3 forms a toner image by, for example, a well-known electrophotographic process. The photosensitive drum 4 starts rotating based on a printing operation start signal from a controller, and corresponds to the printing speed of the image forming apparatus. It rotates at the speed and continues until the printing operation is completed.

When the photosensitive drum 4 starts rotating, a high voltage is applied to the corona charger 5, and the surface of the photosensitive drum 4 is uniformly charged. The charged photosensitive drum 4 has a laser beam 6
, An electrostatic latent image is recorded on the surface. When the electrostatic latent image reaches a position facing the developing device 7 with the rotation of the photosensitive drum 4, toner is electrostatically attracted to the electrostatic latent image and a toner image is formed on the photosensitive drum 4.

The sheet P is conveyed by registration rollers 8 in synchronization with the timing at which the toner image formed on the photosensitive drum 4 reaches the transfer position. The toner image formed on the photosensitive drum 4 is sucked onto the sheet P by the action of the transfer unit 9 that applies a charge of the opposite polarity to the toner image on the back side of the sheet P, and then the toner image is separated by the action of the separator 10. The held paper P is separated from the photosensitive drum 4 and is conveyed to the fixing device 12 by the conveyance belt 11.

The paper P that has reached the fixing device 12 is nipped and conveyed while being heated and pressed by a nip formed by a pair of fixing rollers including a heating roller 12a and a pressure roller 12b. It is fused and fixed. The sheet P sent out by the fixing roller is discharged onto the tray 13. Note that the area of the photosensitive drum 4 that has passed the transfer position is cleaned by the cleaning device 14 and prepared for the next printing operation.

The vertical transport section a ₃ includes a sheet transport path 15 for communicating between the sheet feeding means 2 and the image forming section a _2, and a sheet transport path 1
Provided within 5, and a conveying means (conveying rollers) 16 for guiding the sheet P fed from the paper feeding means 2 to the image forming unit a _2. Further, an opening / closing cover constituting the paper transport path 15 is provided to be freely openable and closable about a shaft 18 as a fulcrum.

Reference numeral 19 denotes a paper feed path, which is provided as a paper transport path for communicating the paper feed unit a _{1, the} image forming means 3 and the tray 13. Reference numeral 20 denotes a draw-in path, which is provided to the image forming unit 3 by branching from a paper feed path 19 on the downstream side in the sheet transport direction, and selectively switches sheets fed from the fixing device 12 by switching control of the flaps 21. Draw in.
22 is a return path, which branches off from the middle of the drop-in path 20,
The terminal end is joined to the paper feed path 19 on the upstream side of the image forming means 3 in the paper transport direction.

Therefore, when performing image recording on both sides of the sheet, the sheet sent from the fixing device 4 is fed into the drawing path 2.
0, and the drawn-in sheet is sent to the return path 22, so that the sheet on which single-side recording has been performed is sent again to the image forming means, whereby double-sided image recording is performed. In the drawing, reference numerals 23 and 24 denote transport rollers provided before and after the flap 21, and reference numerals 25 and 26 denote transport rollers provided on the pull-in path 20 and capable of switching between normal rotation and reverse rotation.
A guide member 7 guides the sheet drawn into the drawing path 20 to the return path 22 or guides the sheet to return to the sheet feeding path 19 side. A guide member 28 is fed from the sheet feeding section a ₁ or the return path 22. A guide member 29 for guiding the sheet to the registration roller 8 side, a sheet path switching member 29 (details will be described later), a sheet detection sensor 30 for detecting the leading end of the sheet immediately after the conveyance roller 31, and a sheet feeding unit a ₁ This is used to temporarily stop the paper near the transport roller 31 in order to take timing with the paper sent from the printer.

The paper path switching member 29 is rotatably supported about a shaft 29a as shown in FIG. 2, and normally joins the return path 22 and the paper feed path 19 as shown in FIG. It is positioned so as to form a paper feed path 32.

In the above configuration, the paper jam, for some reason, if the need to remove the paper that has stagnated in the return path 22 has occurred, the paper path switching member by opening the cover 17 constituting the vertical transport unit a ₃ 29 to FIG.
As shown in FIG. 7, the paper supply path 32 is closed, and a paper discharge path 33 for sending out the paper conveyed through the return path 22 in a substantially horizontal direction is formed below the paper path switching member 29. At the same time as the formation of the paper discharge path 33 or after a lapse of a predetermined time, the transport roller 31 is driven to rotate, and the return path 2
2 is discharged to the outside.

When the discharge of the stagnated paper is completed, the opening / closing cover 17 is opened.
Is closed, the paper path switching member 29 returns to the state shown in FIG. The paper path switching member 29 may be configured by connecting the paper path switching member 29 and the open / close cover 17 by a cam unit or a link unit so as to rotate in conjunction with the opening / closing operation of the open / close cover 17. , Opening and closing cover 1
7 may be independent of the opening / closing operation.

[0020]

As described above, according to the present invention, the paper stagnated near the junction of the return path and the paper feed path can be discharged almost straight from the return path. Space can be minimized,
Workability of taking out the paper and downsizing of the apparatus can be realized.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of an image forming apparatus according to the present invention.

FIG. 2 is a side view of a state in which a paper path switching member forms a paper feed path.

FIG. 3 is a side view of a state in which a paper path switching member forms a paper discharge path.

FIG. 4 is a configuration diagram showing a conventional technique.

[Explanation of symbols]

17: Opening / closing cover, 28: Guide member, 29: Paper path switching member, 30: Paper detection sensor, 31: Transport roller.

Claims (3)

[Claims] An image forming means for recording and forming an image on a conveyed sheet; and a paper feed path for communicating a paper discharge section for accommodating the image-recorded sheet; A retraction path provided by branching from a paper feed path on the downstream side in the transport direction, and a branch from the middle of the retraction path, and its end is joined to the paper feed path on the upstream side in the paper transport direction with respect to the image forming means. In the image recording apparatus having a return path, a sheet conveyed through the return path is guided again to the image forming unit along the paper path at a junction of the return path and the paper path. A paper path switching member supported so as to be switchable between a paper feed path and a paper discharge path for sending out the paper conveyed in the return path in a substantially horizontal direction is provided, and the paper conveyed along the paper discharge path is provided. Open the paper feed path at the location facing the leading end. An image recording apparatus, comprising: an opening / closing cover. 2. An image recording apparatus according to claim 2, wherein the path switching by said paper path switching member is linked to the opening / closing operation of said opening / closing cover. 3. A paper feeding apparatus according to claim 1, wherein a conveying roller provided along said sheet discharge path is rotated in accordance with an opening operation of said opening / closing cover, and sheets stagnated in said return path are discharged from said sheet discharge path. 3. The image recording apparatus according to claim 1, wherein