JP2003341869A - Multi-fed paper sheet separating mechanism of electrophotographic printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multi-fed paper sheet separating mechanism of an electrophotographic printer for surely separating multi-fed paper sheets from each other to stably transport the paper sheet even if a number of paper sheets are picked at a time. <P>SOLUTION: This multi-fed paper sheet separating mechanism of an electrophotographic printer includes a front paper feed roller, a rear paper feed roller, a separation roller provided opposite to the rear paper feed roller, a brake for applying rotation braking force to the separation roller in the direction opposite to the paper running direction, a separation roller holder for rotating the separation roller round the position different from the center of the separation roller, a pressure spring for applying pressure to a nip part between the rear paper feed roller and the separation roller, and a separator provided in contact with the rear paper feed roller R. A sheet guide is provided between the front paper feed roller and the rear paper feed roller on the opposite side to the separator with a sheet path taken as the border between them. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multifeed sheet separating mechanism for an electrophotographic printer.

[0002]

2. Description of the Related Art A double-fed sheet separating mechanism of a conventional electrophotographic printer will be described with reference to FIG. The conventional double-feed separating mechanism is composed of a front paper feeding roller 4, a rear paper feeding roller 5, a separating roller 6, a brake 7, a separating roller holder 8, a pressure spring 9, and a separating separator 10. It was

[0003]

In the double-feed sheet separating mechanism of this type, the sheet fed out by the sheet feeding roller 4 has its leading end abutted against the nip portion between the sheet feeding roller 5 and the separating roller 6 or the separating separator 10. There is a tendency that the contact force between the paper feed roll 4 and the paper feed roll 5 buckles due to the contacting reaction force and the contact angle with the separation separator 10 increases. Since the contact angle becomes large, the shearing force applied to the paper is reduced by the separation separator 10 for separating the multiple sheets of the multi-fed sheet, and the double-fed sheet separation mechanism cannot perform the double-fed separation. There was a problem of frequent occurrence.

It is an object of the present invention to provide a multi-feed sheet separation mechanism for an electrophotographic printer which can reliably perform multi-feed separation even if a large number of sheets are picked at one time. .

[0005]

The above object can be achieved by providing a roller-shaped or plate-shaped sheet guide between the front paper feeding roller and the rear paper feeding roller.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIGS.

First, an example of mounting the multi-feed sheet separating mechanism of the present invention will be described with reference to FIG. 1 by exemplifying a cut sheet electrophotographic printer. In FIG. 1, the paper 1 on the table 2
Is picked up by the front paper feed roller 4 and separated from the multi-feed paper by a multi-feed paper separation mechanism section including the rear paper feed roller 5, the separation roller 6, the separation separator 10 and the guide roller 11, and the timing with the paper conveyance roller 13 It is conveyed to the registration roller 15 by the roller 14. The sheet 1 is conveyed by the registration rollers 15 in synchronization with the rotation of the photosensitive drum 16,
The toner image 17 on the surface of the photosensitive drum 16 is transferred onto the surface of the paper 1 by the transfer device 18. Further, the toner image 17 on the sheet 1 conveyed to the fixing device 19 is pressed and heated by the fixing device 19 to be fixed on the sheet 1. Transport roller 2 from fixing device 19
The sheets 1 conveyed to the stacker 21 by 0 are stacked. The printing operation is continued by repeating the above operation.

Next, the structure and mechanism of the sheet feeding device will be described in detail with reference to FIGS. The multi-feed sheet separating mechanism includes a front paper feed roll 4, a rear paper feed roll 5, and a separation roll 6.
The front side paper feed roller 4, the roller drive motor 12 for driving the rear side paper feed roll 5, the separation roller 6 provided to face the paper feed roller 5, and the paper running direction of the separation roller 6. Brake 7 that applies rotational braking force to the opposite direction
And a separation roller holder 8 that can rotate the separation roller 6 around a position different from the center of the separation roller 6, and a pressure spring 9 that applies pressure to the nip portion between the rear paper feed roller 5 and the separation roller 6. A separating separator 10 provided so as to come into contact with the rear paper feed roller 5, and a front paper feed roller 4.
And a roller-shaped sheet guide 11 provided between the rear sheet feeding roller 5.

Next, the mechanism of the multi-feed sheet separating mechanism of the present invention will be described with reference to FIG. When a large number (three or more) of double-fed sheets are picked up by the front side paper feed roll 4 and the leading edge of the sheets comes into contact with the separation separator 10 and the portion near the leading edges of the sheets is deformed upward, the sheet guide 11 The contact pressure between the separation separator 10 and the sheet 1 is increased by the pressure. In particular, since the downward force is applied to the lower sheet of the multi-feed sheets due to the rigidity of the upper sheet, the lower sheet has a larger contact pressure with the separation separator 10. As a result, the lower sheet of the multi-fed sheets has a large contact pressure with the separation separator 10 and thus can be separated and stopped by the separation separator 10. At this time, the upper two sheets can be separated. Even when traveling to the nip portion between the rear paper feed roller 5 and the separation roller 6 without doing so, the separation roller 6 can separate the double-fed sheets, and even in this case, the double-fed sheet can be prevented.

The same effect can be obtained even if the sheet guide 11 is a plate-like member having a spring property.

[0011]

As described above, according to the present invention, it is possible to prevent the double feeding of a large number of sheets, and it is possible to provide the double feeding sheet separating mechanism of the electrophotographic printer which can obtain the stable sheet feeding.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of the present invention.

FIG. 2 is a configuration diagram showing an embodiment of a multi-feed sheet separating mechanism of the present invention.

FIG. 3 is a perspective view showing a part of FIG.

FIG. 4 is an enlarged side view showing an embodiment of the double-fed sheet separating mechanism of the present invention.

[Explanation of symbols]

1 ... Paper, 2 ... Table, 3 ... Paper feed frame, 4 ... Paper feed roller F, 5 ... Paper feed roller R, 6 ... Separation roller, 7 ... Brake, 8 ... Separation roller holder, 9 ... Pressure spring ,
10 ... Separation separator, 11 ... Sheet guide, 12 ... Roller driving motor, 13 ... Paper transport roller, 14 ... Timing roller, 15 ... Registration roller, 16 ... Photosensitive drum, 17 ... Toner image, 18 ... Transfer machine, 19 ... Fixing machine, 2
0 ... Transport roller.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Eita Sakaba             Hitachiko, 1060 Takeda, Hitachinaka City, Ibaraki Prefecture             Machine Co., Ltd. F-term (reference) 3F343 FA02 FB02 FC01 FC03 GA01                       GB01 JD09 KA03 KA13

Claims (4)

[Claims] 1. A front paper feed roller, a rear paper feed roller, a separation roller provided to face the rear paper feed roller, and a rotation braking force on the separation roller in a direction opposite to the paper running direction. A separating roller holder that can rotate the separating roller about a position different from the center of the separating roller, and a pressure that applies pressure to the nip portion between the rear paper feeding roller and the separating roller. In a double-fed sheet separating mechanism of an electrophotographic printer, which comprises a pressure spring and a separating separator provided so as to contact the rear side sheet feeding roller R, between the front side sheet feeding roller and the rear side sheet feeding roller. A multi-feed sheet separating mechanism for an electrophotographic printer, wherein a sheet guide is provided on the opposite side of the separating separator with a sheet path as a boundary. 2. The multi-feed sheet separating mechanism for an electrophotographic printer according to claim 1, wherein the sheet guide is a roller sheet guide. 3. The multi-feed sheet separating mechanism for an electrophotographic printer according to claim 1, wherein the sheet guide is a plate-shaped sheet guide. 4. The multi-feed sheet separating mechanism for an electrophotographic printer according to claim 3, wherein the plate-shaped sheet guide has a spring property. [Means for Solving the Problems]