JP2802078B2 - Paper transport guide device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper conveyance guide device used for a copying machine, a printer, a facsimile, a collator, and the like.

2. Description of the Related Art Conventionally, in an image recording apparatus such as a copying machine or a printer for recording an image on a recording sheet, the recorded sheet is discharged in a haze-up or haze-down state. There is a need for a paper transport guide device for transport path switching that reverses and transports the paper inside.

Japanese Patent Application Laid-Open No. Sho 63-117833 discloses a technique for guiding the sheet conveyance. In a sheet feeding apparatus having three switching rollers, the position of the switching roller is switched so that the sheet is inverted and conveyed. There is disclosed a technique of directly conveying a sheet or switching a sheet conveying direction by a branch claw.

[Problems to be Solved by the Invention] However, the above-mentioned conventional paper feeding apparatus requires complicated paper guiding means in accordance with the paper transport direction. SUMMARY OF THE INVENTION It is an object of the present invention to provide a paper conveyance guide device which has a simple configuration and can prevent erroneous conveyance in a conveyance direction when a conveyance path is switched.

[Means for Solving the Problems] A paper transport guide device according to the present invention is a paper transport guide device including a transport direction switching device for a paper, a reversal guide device for reversing the transport direction, and a hase-up paper receiving tray. The conveyance direction switching means includes a first roller pair and a second roller pair which convey and rotate the sheet by sandwiching the sheet between the rollers. When the sheet is reversed and conveyed, the sheet is conveyed to the reversing guide means by the first roller pair, and then leaves the nib portion of the first roller pair and moves along one roller of the roller pair. When the rear end of the moving paper is brought into contact with the nib portion of the second roller pair and conveyed reversely and discharged to the haze-up discharge receiving tray, the gap between the rollers of the second roller pair is released and the conveyance force of the roller pair is released. To cancel doing.
The present invention is also characterized in that the first roller pair and the second roller pair share one roller.

[Operation] By configuring the paper transport guide device as described above, the paper reversing transport mechanism has a simple configuration, and when the paper is discharged to the haze-up discharge receiving tray, the transport of the second roller pair is performed. Since the force is released, the paper is not drawn into the reverse conveyance path.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a partial cross-sectional side view for explaining an embodiment of the present invention. A sheet placed on a sheet feed tray 1 is fed into an image recording apparatus by a pickup roller 2, and a pair of transport rollers By 3a, the recording drum 4 is conveyed to a position close to the drum surface. Around the recording drum 4, a cartridge 4a for recording an electronic latent image on the recording drum 4, a developing unit 4 for developing the electronic latent image
b, transfer unit 4c for transferring toner to paper, cleaning unit 4d for removing transfer residual toner
And an eraser unit 4e for removing the residual charges.

When the paper passes between the recording drum 4 and the transfer unit 4c, the paper is charged by corona discharge of the transfer unit 4c, adsorbs the toner on the recording drum 4, and passes along the edge of the transport unit 5 via the transport rollers 3b. The image is fixed by a fixing unit 6 having a heating roller and a pressure roller through a conveyance path 5a indicated by a two-dot chain line, and further includes a first, second, and third roller 8a, 8b, 8c for conveyance. The first roller 8a and the second roller 8b of the transport direction switching means 8 having rollers and having the rotation center of the clamshell as the rotation axis 7 are fed to a haze-down paper discharge path or a reverse recording transport path. When the paper is transported, the second roller 8b is rotated counterclockwise about the rotation shaft 7, and the first roller 8a and the third roller 8c are rotated clockwise. The first roller 8a and the second roller 8b form a first roller pair, and the second roller 8b and the third roller 8c form a second roller pair. The paper is held and transported in the nip where the paper contacts.

In order to transport the paper recorded as described above in a required direction, a gate 9, a paper guide unit 10, an R paper guide 11,
There is provided a sheet guiding means including a reversing guide section 14 and the like. If the paper is to be discharged in the first direction, that is, in the haze-down state, the gate 9 for changing the paper conveyance direction should be set to the state shown by the solid line in FIG. Paper guide section 10, R paper guide
The paper is guided by the gate 11 and the gate 9 and is discharged to the haze-down discharge tray 12. Note that the paper guide unit 10 also serves as a haze-up discharge receiving tray when the back surface of the paper guide unit 10 is tilted to the rear left side in the drawing to the second position.

When reverse recording is performed on the back surface of the sheet, a magnet (not shown) is driven to move the gate 9 to a position indicated by a broken line with the gate shaft 9a as a rotation axis. When the transport path is switched in this way, the paper is fed to the paper guide section 10 and the R paper guide 1.
First, after being guided by the gate 9 and the reversing guide rib 13 and temporarily introduced into the reversing guide portion 14, a second roller in which the rear end of the sheet is formed by the second roller 8b and the third roller 8c of the transport direction switching means 8 The sheet is bitten by the pair, placed in a reversing conveyance path 5b provided along the lower edge of the conveyance unit 5 and reversed and conveyed, and an image is recorded on the back surface of the sheet.

The gate 9, the paper guide section 10, the R paper guide 11, and the reversing guide rib 13 each have a comb-shaped rib structure, and the portions overlapping each other in the drawing do not collide with each other in the thrust direction. A rib is provided at the position.

2 and 3 are enlarged views of the upper part of the image recording apparatus shown in FIG. 1, and FIG. 2 is a view in which the paper guide section 10 is in the first position as in FIG. FIG. 3 is an explanatory view of an embodiment in which the sheet guide unit 10 is tilted to the second position, and the sheet guide unit 10 is also used as a discharge tray for a haze-up sheet discharge.

Figure 2, in Figure 3, a second conveying direction switching means 8
The roller 8b is a transport roller driven and rotated about a rotary shaft 7 coaxial with the center of rotation of the clamshell. The transport unit 5 and the paper guide 10 also rotate about the rotary shaft 7. The bearing 8e of the third roller 8c is fitted in the slide groove 10a of the paper guide portion 10, and the third roller 8c is pressed against the second roller 8b by a spring 10b. ,
The bearing 8d of the first roller 8a is also pressed against the surface of the second roller 8b by a spring (not shown), and follows the rotation of the second roller 8b.

In FIG. 2, the first roller 8a has its bearing 8d sandwiched between the lug 10c of the paper guide unit 10 and the lug 5c of the transport unit 5, and the position with respect to the second roller 8b is such that the paper is moved in the first direction. In other words, the haze-down discharge or reversal guide section 13
The position is optimally set for the conveyance to the conveyance path.

FIG. 3 shows a state in which the paper guide unit 10 is rotated counterclockwise about the rotation shaft 7 and is tilted to the second position. Therefore, the bearing 8d of the first roller 8a is The sheet moves to a position defined by the ear 10d of the paper guide 10 and the ear 5d of the transport unit 5.

A play angle is provided between the both ears 10c and 10d of the paper guide unit 10 and the both ears 5c and 5d of the transport unit 5, and the paper guide unit 10 is tilted to the second position by the play angle. When used as a paper receiving tray, the moving angle of the first roller 8a with respect to the second roller 8b should be smaller than the moving angle when the paper guide unit 10 moves from the first position to the second position. Thus, the first roller 8a can be set in the second direction, that is, the position most appropriate for discharging the paper onto the back surface of the paper guide unit 10 used as a paper receiving tray.

2 and 3, reference numeral 5e denotes a transport unit 5.
The cam is provided on the side surface of the third roller. As shown in FIG. 2, when the paper guide unit 10 is at the first position, the third roller
Although the bearing 8e of 8c is at a position away from the cam 5e, when the paper guide unit 10 moves to the second position as shown in FIG. 3, the bearing 8e of the third roller 8c rides on the cam 5e. Separates from the second roller 8b. That is, the second roller pair is separated and the sheet transport function is released. Therefore, the paper guide section 10
When the sheet is in the second position and is used as a sheet receiving tray, the sheet discharged onto the sheet guiding section 10
You will not be drawn into 5b.

The present invention is not limited to the above-described embodiment, and can be modified and implemented without changing the gist.

[Effects of the Invention] The paper transport reversing mechanism is constituted by a simple mechanism, and furthermore, the paper discharged on the hase-up paper receiving tray can be prevented from flowing back to the reverse transport path, so that the configuration of the paper transport guide device is simplified. it can.

[Brief description of the drawings]

FIG. 1 is a partial side sectional view for explaining an embodiment of the present invention, and FIGS. 2 and 3 are enlarged views of an upper portion of FIG. 1, respectively. 1 ... paper feed tray, 2 ... pickup roller 3a ... transport roller pair, 3b ... transport roller 4 ... recording drum, 4a ... cartridge 4b ... developing unit, 4c ... transfer unit 4d ... cleaning Unit, 4e Eraser unit 5 Transport unit, 5a Transport path 5b Reverse transport path, 5c, 5d Ear 5e Cam 6 Fixing unit 7 Rotating shaft 8 ... Conveyance direction switching means 8a first roller 8b second roller 8c third roller 8d 8e bearing 9 gate 9a gate shaft 10 paper guide section 10a … Slide groove 10b… Spring, 10c, 10d… Ear part 11… R paper guide, 12… Haze-down discharge tray 13… Reversal guide rib, 14… Reversal guide part

Claims (2)

(57) [Claims] 1. A sheet conveyance guide device comprising a sheet conveyance direction switching unit, a reversing guide unit for reversing the conveyance direction, and a haze-up sheet receiving tray, wherein the conveyance direction switching unit sandwiches the sheet between rollers. A first roller pair and a second roller pair that rotate and convey are disposed close to each other, and a unit that releases between the rollers of the second roller pair to release the conveying force is provided, and the sheet is turned over. In the case of transporting, after transporting the paper to the reversing guide means by the first roller pair, the trailing edge of the paper that moves along one of the rollers of the first roller pair after leaving the nib portion of the first roller pair is described above. When the sheet is inverted and conveyed by being bitten by the nib portion of the second roller pair, and discharged to the above-mentioned Hays-up discharge receiving tray, the second
A sheet conveyance guide device for releasing the conveyance force of a pair of rollers by releasing the space between the rollers. 2. The paper transport guide device according to claim 1, wherein the first roller pair and the second roller pair share one roller.