JP3284174B2 - Prevention of paper corner breakage in U-turn paper feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a cut sheet conveying device such as a copying machine and a printer, and more particularly, to a device for correcting a bent sheet.

[0002]

As A conventional techniques and to be Solved by the Invention Conventional techniques, JP-open flat 3-223047, the interior of the U-turn conveying path, positioned above the lower paper guide U-turn conveying path paper angle bending prevention device is disclosed in in the width direction the cassette U-turn sheet feeding, characterized in that the auxiliary paper guide is disposed to the portion corresponding to the preparative pawl having a free passage space of the paper curl device .

[0003] In the prior art, in order to prevent bending sheet angle, is provided with the auxiliary paper guide having a free passage space of the newly paper curl, the sheet feeding apparatus having a plurality, a plurality of sheet transport path It is difficult to provide an auxiliary paper guide in terms of space because of the existence of the paper guide.

Accordingly, in order to solve the above-mentioned problems, the present invention provides a part of a paper guide of a plurality of paper transport paths to have a role of the above-mentioned auxiliary paper guide, and a paper angle in a small space. An object of the present invention is to provide a paper angle preventing mechanism in a U-turn sheet feeding device that establishes a folding preventing mechanism.

[0005]

In the U-turn paper feeder according to the present invention , the paper angle bending prevention mechanism is provided for feeding paper one by one from the uppermost paper in the cassette in cooperation with a paper feed roller and a cassette claw. A plurality of paper devices are provided, and the paper sent from the upper paper feeder passes through the inner U-turn transport path, and the paper sent from the lower paper feeder is transported to the outer U-turn transport. In the U-turn sheet feeding device, both sheets are finally sent to a pair of sheet conveying rollers disposed in the middle of the U-turn conveying path, and further fed out by the pair of sheet conveying rollers. the free passage space of the paper curl portion formed substantially apex portion paper guides corresponding to said cassette pawl in the width direction portion of the U-turn conveying path, the full
Space through the outer U-turn transport path
The paper guide is used to return the paper curl.
This is a mechanism for preventing a paper corner from being bent in a U-turn paper feeder that functions as a guide for quickening .

[0006] According to the paper corner folding prevention mechanism in the U-turn paper feeder of the present invention , the paper guides inside the plurality of paper transport paths are provided with a free passage space of the paper curl portion in a portion corresponding to the cassette claw in the width direction. Provided , the free passage sky
Between the outer U-turn transport path space,
The paper guide guides the paper
It functions as a key.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, U of an embodiment of the present invention will be described.
The paper sheet folding prevention mechanism in the turn sheet feeding device will be described with reference to the drawings.

FIG. 1 is a main sectional view of an electrophotographic image forming apparatus according to the present invention. FIG. 1 shows an overall configuration of an image forming apparatus according to an embodiment of the present invention. As shown in this figure, in the image forming apparatus of the present embodiment, a paper feed cassette 2 is installed at a lower portion of the image forming apparatus main body. In the center of the inside of the image forming apparatus main body 1,
A photoreceptor drum 3 is rotatably provided, and a charging charger 4, an eraser lamp 5, a developing device 6, a transfer charger 7, and a cleaning device 8 are arranged on the outer peripheral portion thereof, and constitute a copying process unit. Further, a fixing device 9 is provided on the paper discharge side of the photosensitive drum 3.

A paper feed cassette 2 is detachably attached to a lower portion of the main body 1 of the image forming apparatus. Inside the paper feed cassette 2, paper 12 is placed on a rotating plate 11 pushed upward by a spring 10. The paper 12 has a cassette claw 13
Is found hold both ends of the sheet feed direction front end by. The rear end of the paper 12 is regulated by a rear end plate 14. A paper feed roller 15 is provided above the paper feed cassette, and the paper feed roller 15 is driven to rotate by a paper feed drive motor (not shown). The paper 12 stored in the paper feed cassette 2 is sequentially fed from the top by a paper feed roller 15, and is selectively fed one by one to a transport path 16.

[0010] the conveying path 16 is installed a plurality of paper transporting rollers 17, these paper transport rollers 17 transport driving motor (not shown), the paper feed roller 1 5
It is driven to rotate in conjunction with. A registration roller 18 is provided in front of the photosensitive drum 3. A paper detection sensor 19 is provided on the transport path 16 on the front side of the registration roller 18. Further, the discharge tray 1 0 is provided to the discharge side of the fixing device.

A contact glass 20 for placing a document is provided at the upper part of the main body of the image forming apparatus, and an optical unit 21 is provided below the contact glass 20. Copy lamp 22 optical system unit 21 performs exposure of the original on the contact glass 2 0, a plurality of mirrors 23,
A copy lamp 22 and a mirror 23 can be scanned by an optical drive motor (not shown). In particular, the copy lamp 22 can be moved a specific distance by a stepping motor. A document cover 25 is provided above the contact glass 20, and a document pressing mat 26 is attached below the document cover 25.

FIG. 2 is a side view of a main part of the paper angle preventing mechanism, and FIG. 3 is a sectional view taken along the line P--P in FIG. In FIG. 2, there are two paper feeders that feed out one sheet at a time from the top sheet 12 in the cassette in cooperation with the paper feed roller 15 and the cassette claws 13. The paper sent from the paper feeding device located above is sent to the first U-turn conveyance path 2
7 and is fed to a sheet transport roller 17 disposed in the middle of the U-turn transport path.

Further, the sheet 12 sent from the sheet feeder located below passes through the sheet conveying roller 17 once, passes through the second U-turn conveying path 28, and is conveyed in the middle of the U-turn conveying path. It is sent to the roller 17.
Finally, the paper fed from the upper and lower paper feeders is sent to the paper transport roller 17.
Therefore, the first U-turn transport path 27 and the second U-turn transport path 28 are located very close to each other with the first U-turn paper guide 29 interposed therebetween. Also,
The upper and lower sheet feeding devices do not feed out sheets at the same time.

2 and 3, the width of the first U-turn paper guide 29 is the same as that of the second U-turn paper guide 30.
The free passage section 31 of the curl portion a formed at the left and right corners 12a of the leading end of the paper 12 is formed at a portion corresponding to the pair of left and right cassette claws 13 in the paper feed cassette 2 on both sides thereof. ing.

The paper 12 fed away from the paper cassette 2 by the rotation of the paper feed roller 15 and separated from the cassette claw 13 is supported by the upper surface of the first U-turn paper guide 29 at portions other than the curl portions a at both ends thereof. It is guided toward the transport roller 17. The curled portions a at both ends of the paper 12 pass through the free passage sections 31 on both sides of the first U-turn paper guide 29.
Gives time to restore to the original plane naturally,
After restoring on a plane or at the final stage of restoring, the second U
The paper is fed to the paper transport roller 17 while being in contact with and guided by the turn paper guide 30. When the sheet is fed to the paper transport roller 17, the corner 12a is restored to the planar shape b as shown by the two-dot chain line in FIG.

In addition, the present invention is not limited to the embodiment described above and shown in the drawings, and it is needless to say that the present invention can be appropriately modified and implemented without departing from the scope of the invention.

[0017]

According to the mechanism for preventing the paper corner from being folded in the U-turn paper feeder of the present invention , the space of the second U-turn conveyance path 28 is provided in the space of the free section 31 of the curl portion a formed at the left and right corners 12a at the leading end of the paper 12. that use. Therefore, the U-turn paper feeder itself can be reduced in size.

According to the present invention , the second U-turn paper guide 29 also serves as a guide for accelerating the return of the curled portion a.

[Brief description of the drawings]

FIG. 1 is a main cross-sectional view of an electrophotographic image forming apparatus according to an embodiment of the present invention.

FIG. 2 is a side view of a main part of the paper corner fold preventing mechanism according to the embodiment of the present invention;

FIG. 3 is a sectional view taken along the line PP in FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Copier main body 2 Paper feed cassette 3 Photoreceptor drum 4 Charger 5 Eraser lamp 6 Developing device 7 Transfer charger 8 Cleaning device 9 Fixing device 10 Spring 11 Rotating plate 12 Paper 13 Cassette claw 14 Rear end plate 15 Feed roller 16 Transport Path 17 Paper transport roller 18 Registration roller 19 Discharge tray 20 Contact glass 21 Optical unit 22 Copy lamp 23 Mirror 24 Lens 25 Document cover 26 Document holding mat 27 First U-turn transport path 28 Second U-turn transport path 29 First U-turn paper Guide 30 2nd U-turn paper guide 31 Free passage

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-8-59008 (JP, A) JP-A-3-223047 (JP, A) JP-A-5-54454 (JP, U) (58) Field (Int.Cl. ⁷ , DB name) B65H 5/38 B65H 3/44 B65H 3/68 B65H 15/00

Claims (1)

(57) [Claims] 1. A paper feeder which feeds out one sheet at a time from the uppermost sheet in a cassette by cooperation of a paper feed roller and a cassette claw, and is fed from a paper feeder located above. The paper passes through the inner U-turn transport path, and the paper sent from the paper feeder located below passes through the outer U-turn transport path, and both sheets are finally disposed in the middle of the U-turn transport path. In the U-turn paper feeding device, the paper guide is fed to the pair of paper transport rollers and further fed out by the pair of paper transport rollers. scan of the part provided with the free passage space of the paper curl, the free passage space of the outer U-turn conveying path
The paper guide is used for the paper curl part.
A paper corner break prevention mechanism in a U-turn paper feeder that functions as a guide to speed recovery .