JPH0373732A - Paper feeding device - Google Patents

Abstract

PURPOSE:To surely return a paper meshed between a transport roller and a separating roller to a paper feeding cassette side by constituting a paper feeding device so that the transport roller and the separating roller which constitute a paper feeding means are reversely revolved to the paper feeding cassette side after the completion of copying operation. CONSTITUTION:After a completion of copying operation by an image forming device body, a transport roller 23 and a separating roller 24 which constitute a paper feeding means are revolved reversely towards a paper feeding cassette 9 side. Therefore, driving the continuous copying operation by the image forming device body, even if the multiple feed of the final copying paper P by a pick-up roller 12 arises, the paper P meshed between the transport roller 23 and the separating roller 24 can be surely returned to the paper feeding cassette 9 side.

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of the Invention (Industrial Application Field) The present invention relates to a paper feeding device with an improved paper feeding structure applied to an image forming apparatus such as an electronic copying machine. It is.

(Prior Art) Conventionally, in a paper feeding device of this type of image forming apparatus, paper in a paper feeding cassette is taken out by a pickup roller and transferred to the image forming apparatus through a paper feeding means consisting of a conveyance roller and a separation roller. Paper is fed into the main unit one by one.

(Problem to be Solved by the Invention) However, in a paper feeding device having such a conventional structure, the final sheet to be copied is fed multiple times by the pickup roller during continuous copying operations by the main body of the image forming apparatus. and after copying is complete.

There is a problem in that the multiple-fed sheets remain in the main body of the image forming apparatus in a half-finished state, stuck between the conveyance roller and the separation roller, and this causes problems in the next sheet feeding operation.

The present invention has been made under the above circumstances, and an object of the present invention is to provide a paper feeding device that prevents multiple fed sheets from remaining inside the main body of an image forming apparatus after copying is completed. It is about providing.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides a paper feed cassette that is removably loaded into a paper feed section of an image forming apparatus main body, and an ejection means for ejecting paper from the paper cassette;
The paper feeding means separates and feeds the sheets taken out by the taking out means to the main body of the image forming apparatus one by one. and means for reversing the paper toward the paper feed cassette after the image forming apparatus main body completes copying.

(Function) That is, in the present invention, after the image forming apparatus main body finishes copying, the conveyance roller and the separation roller that constitute the paper feeding means are reversely rotated toward the paper feed cassette, so that the image forming Even if the final sheet to be copied is multiple-fed by a pick-up roller during continuous copying operations by an apparatus main body, the sheet caught between a conveying roller and a separating roller is surely returned to the sheet feeding cassette side.

(Example) Hereinafter, the present invention will be described in detail with reference to an illustrated example.

FIG. 2 schematically shows the internal mechanism of an electronic copying machine which is an image forming apparatus equipped with a paper feeding device according to the present invention, and numeral 1 in the figure is the main body of the apparatus. A drum-shaped photoreceptor 2 serving as an image carrier is rotatably supported approximately at the center of the apparatus main body 1, and the photoreceptor 2 is uniformly charged by a charger 3. At the same time, a document image (not shown) placed on a document table 4 made of transparent glass is exposed to an exposure lamp 5a, first, second, and third reflecting mirrors 5b,
5c, 5d, a lens 5e, and a fourth reflective mirror 5f to form an electrostatic latent image on the latent image surface 2a of the photoreceptor 2, and develop this electrostatic latent image. A device 6 applies a developer to develop the image, and the device 6 rotates the image to the transfer charger 7 side.

This transfer charger 7 is automatically or manually fed from a paper feed cassette 8.9 loaded into the paper feed opening 1a of the apparatus main body 1, and fed through a paper feed device 20 and aligning roller pair 10, which will be described later. The developed image is transferred onto paper P, which is then separated by AC corona discharge charger 1.
1 to be peeled off.

Further, the paper P after transfer and peeling is peeled off from the photoreceptor 2 by a separating device to be described later, passes through a conveyance path 12, and the developed image is melted and fixed by a fixing device 13. This is what is discharged.

Furthermore, the developer remaining on the latent image surface 2a of the photoreceptor 2 after the transfer and peeling of the developed image to the copy paper P is cleaned by the cleaning device 16, and the potential on the photoreceptor 2 is reduced by the static elimination lamp 17. The level is set below a certain level to enable the next copying operation.

As shown in FIG.
A pick-up roller 21 and a transport roller 23 supported by a drive shaft 22 which is rotatably driven in the paper feeding direction (arrow A1) by an opening system (not shown) are used as a take-out means for taking out the paper. The separation roller 24 constitutes a paper feeding means.

It is attached to the drive shaft 25, and usually a spring clutch (
The conveyance roller 2 is
The drive shaft 25 (not shown) is designed to rotate along with the drive shaft 3 in the paper feeding direction A2, and receives a load when multiple sheets of paper P in the paper feed force cellar 1-8.9 are fed. Due to the opening system, the direction opposite to the paper feeding direction (dotted arrow B
By reversing the rotary motion to Z),
The multi-fed sheets P are separated, so that the sheets P are fed one by one to the aligning roller pair 10 side.

Further, the conveyance roller 22 and the separation roller 23 are
As shown in the figure, after the image forming apparatus completes copying, it is controlled to reverse direction B1, B2 toward the paper feed cassette 8 or 9, and thereby, during continuous copying operation, the final paper P to be copied is When the pickup roller 21 is causing multiple feeding, the paper P caught between the transport roller 23 and the separation roller 24 is returned to the paper feed cassette side. In this case, the pickup roller 21 is It is raised by a drive system that does not operate and separates from the paper P in the paper feed cassette 8 or 9.

[Effects of the Invention] As is clear from the above description, according to the present invention, after the image forming apparatus main body completes copying, the conveyance roller and the separation roller that constitute the paper feed means are rotated in reverse toward the paper feed cassette. Therefore, even if the final sheet to be copied is multiple-fed by the pickup roller during continuous copying operations by the image forming apparatus main body, the paper caught between the transport roller and separation roller will not be fed. A paper feed system that has excellent effects in that it can be returned to the paper cassette side reliably, so there is no risk of paper remaining inside the image forming apparatus body after copying is completed, and there is no problem with the next paper feeding operation. The device can be provided.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of the main parts of an embodiment of a paper feeding device according to the present invention in a state in which paper is taken out, and FIG. 2 is an electronic copying machine as an image forming apparatus equipped with the paper feeding device according to the present invention. FIG. 3 is a schematic explanatory diagram of the main parts showing the reversed state of the conveyance roller and separation roller after copying is completed. DESCRIPTION OF SYMBOLS 1... Image forming apparatus main body, 8.9... Paper feed cassette, 20... Paper feed device, 21... Pick up roller, 22... Opening shaft, 23... Conveyance roller, 24
... Separation roller, 25 ... Braking shaft. P...Paper.

Claims (1)

[Claims] A paper feed cassette that is removably loaded into the paper feed section of the image forming apparatus main body, a take-out means that takes out the paper in the paper feed cassette, and a take-out means that takes out the paper sheets one by one on the image forming apparatus main body side. and a paper feeding means that separates and feeds the paper, and the paper feeding means reversely rotates the transport roller and the separation roller toward the paper feed cassette after the image forming apparatus main body finishes copying. What is claimed is: 1. A paper feeding device characterized by comprising means for causing