JP3685914B2 - Automatic document feeder - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an automatic document feeder in an image forming apparatus such as a copying machine or a facsimile, and more particularly to an automatic document feeder that facilitates separation of documents.
[0002]
[Prior art]
2. Description of the Related Art Image forming apparatuses such as copying machines and facsimiles use automatic document feeders that automatically take in documents and separate and feed them one by one.
A conventional automatic document feeder of this type is disclosed in, for example, Japanese Patent Laid-Open No. 3-106752. In this apparatus, the uppermost document is fed out from a bundle of documents set horizontally on the document table so as to advance substantially horizontally, and one of them is separated by the separation mechanism and conveyed to the document reading position. ing.
[0003]
[Problems to be solved by the invention]
However, in such a conventional automatic document feeder, the upper document sent out from the document bundle is substantially straight and enters the separation mechanism, so that a plurality of documents above the document bundle are in close contact with each other. Therefore, the paper is fed to the separation mechanism and is not separated well, so that the originals are fed in a so-called double feed tendency.
[0004]
SUMMARY OF THE INVENTION An object of the present invention is to improve the separation of document bundles in an automatic document feeder.
[0005]
[Means for Solving the Problems]
According to the first aspect of the present invention, a document setting unit for setting a document bundle, a sending unit for sending a document from the set document bundle, and a top document among the sent documents are separated from others and placed at a predetermined position. In an automatic document feeder provided with a separating sheet feeding unit, a leading end portion of documents sent from the document bundle is inclined obliquely from below obliquely between the document setting unit and the separating sheet feeding unit. Pre-separation means that facilitates the separation by bending upward is provided, and the document setting unit inclines the document so that the leading end is positioned downward, and the pre-separation means is separated from the delivery unit and the separation unit. A depression that guides the leading end portion of the document bundle between the sheet feeding units and bends the uppermost document obliquely upward toward the separation sheet feeding unit in cooperation with the sending unit. Document feeding in pre-separation means Characterized in that to one having the center of the nip portion of the separation sheet feeding portion and the delivery portion of the direction. Therefore, reliable separation and feeding can be performed by entering the separation and feeding unit in a state where the documents sent from the document bundle are easily separated. Further, the pre-separation means is realized with a simple structure, and the pre-separation means can be realized at low cost.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an embodiment of the present invention, and FIG. 2 shows the main configuration thereof.
In FIG. 1, an automatic document feeder according to an embodiment of the present invention comprises a document table 1, a calling roller 3, a sheet feeding belt 4, a reverse roller 6, and a guide plate 30 to feed a document to a copying machine. It is located upstream of the contact glass 8 of the copying machine.
[0008]
In FIG. 1, reference numeral 1 denotes an original table on which an original bundle 20 is set, which is an original setting portion referred to in the present invention. The calling roller 3 feeds out a bundle of documents 20 set on the document table 1, and only the calling roller 3 serves as a sending unit. Note that the document bundle 20 is a stack of documents, for example, a stack of sheets of cut sheet documents of the same shape, usually made of paper. The paper feeding belt 4 and the reverse roller 6 separate the original bundle 20 fed from the calling roller 3 one by one and feed it to the subsequent path. The paper feeding belt 4 and the reverse roller 6 serve as a paper feeding unit. Yes. A guide plate 30 (pre-separating means) for bending the document bundle 20 between the calling roller 3 (feeding unit), the sheet feeding belt 4 and the reverse roller 6 (separating sheet feeding unit), that is, for local bending. ) The document table 1 is inclined with respect to the contact glass 8 of the copying machine, and the leading edge of the document is positioned below.
[0009]
The guide plate 30 guides the document bundle 20 in a depression 31 (bending guide portion), and cooperates with the calling roller 3 to bend the uppermost document obliquely upward toward the paper feed belt 4 and the reverse roller 6. Let
Since the guide plate 30 is bent downward at the depression 31, the leading ends of the document are bent from the obliquely downward direction to the obliquely upward direction, and the documents are closely connected by utilizing the document feeding and the elastic recovery action. Thus, it is possible to easily separate the original bundle 20 one by one.
[0010]
The shape of the guide part of the depression 31 is preferably the curvature radius of 20 mm at the deepest part. In addition, the depression 31 is substantially at the center of the guide plate 30 and the slopes of the descending slope 32 and the ascending slope 33 are substantially equal.
Next, the operation of the automatic document feeder according to the embodiment of the present invention will be described.
A document bundle 20 is set on the document table 1 and is inserted into the sheet feeding port 13 until it hits the document stop claw 2 as it is. When a copy start button (not shown) on the copying machine main body is pressed, a paper feed motor (not shown) rotates forward. Thereby, the calling roller 3 and the paper feed belt 4 rotate in the clockwise direction, and the reverse roller 6 and the pull-out roller 5 rotate in the counterclockwise direction. At the same time, the document stop claw 2 rises and the calling roller 3 falls. The original bundle 20 is sent to the guide plate 30 by the calling roller 3.
[0011]
In the document bundle 20, the leading end of the document is bent from the obliquely downward direction to the obliquely upward direction by the guide plate 30, and the depression 31 included in the guide plate 30 guides the document bundle 20, and cooperates with the calling roller 3. Therefore, the uppermost document is bent obliquely upward toward the paper feed belt 4 and the reverse roller 6.
FIG. 3 shows a state in which the document bundle 20 is sent out to the guide plate 30 side by the calling roller 3. The document bundle 20 descends to the descending slope 32 of the guide plate 30 and the leading end of the document bundle 20 abuts against the ascending slope 33. The depression 31 guides the document bundle 20 and cooperates with the calling roller 3 to bend the uppermost document obliquely upward toward the paper feeding belt 4 and the reverse roller 6. As a result, a gap g is easily formed between the originals, and the original bundle 20 can be easily separated one by one.
[0012]
The leading edge of the document thus fed out from the document bundle 20 enters the nip portion between the sheet feeding belt 4 and the reverse roller 6, and the sheet feeding belt 4 that rotates clockwise on the upper surface side and the sheet feeding belt 4 on the lower surface side. On the other hand, the reverse roller 6 that rotates counterclockwise with a predetermined speed difference separates the other originals one by one from the uppermost original 21 of the original bundle 20, and the uppermost original is the pull-out roller 5. And it is conveyed to the vicinity of the roller pair 14 interlocked with the pull-out roller.
[0013]
When the leading edge of the document is detected by the pull-out sensor 18 disposed downstream of the pull-out roller 5, the calling roller 3 is raised, and the paper feeding motor that drives the paper feeding belt 4 switches the driving direction from normal rotation to reverse rotation. By stopping the calling roller 3 and the paper feeding belt 4 in the configuration of the drive system, the pull-out roller 5 and the reverse roller 6 remain counterclockwise and prevent the next original from entering the separation unit. In this state, the document 21 is transported by the pull-out roller 5 and the roller pairs 14 and 15 to a transport unit constituted by the transport belt 7 and the contact glass 8. Simultaneously with the reverse rotation of the paper feed motor, a transport motor (not shown) that drives the transport belt 7 rotates in the forward direction, and the document is transported onto the contact glass 8 by the transport belt 7 and stopped at a predetermined position on the contact glass 8. The registration sensor 19 detects the trailing edge of the document conveyed by the conveyance belt 7 and then stops the document at a predetermined position on the contact glass 8 by stopping the conveyance motor after conveying the document by a predetermined number of pulses by the conveyance motor. Let When the conveyance motor rotates forward after the exposure of the copying machine body, the reverse discharge motor simultaneously rotates forward, the reverse discharge roller 11 rotates counterclockwise, and the switching claw 9 When switched to the b direction, the original 21 is discharged as it is to the paper discharge tray 10 by the reverse paper discharge roller 11 and the reverse paper discharge roller pair 12. When the switching claw 9 is switched in the direction a, the paper discharge path is switched to the reverse paper discharge path.
[0014]
According to the present embodiment, as described above, the simple pre-separating means for bending the leading end portion of the document from the obliquely downward direction to the obliquely upward direction by the guide plate 30 is configured. Can be separated and fed. Therefore, reliable separation and feeding can be performed by entering the separation and feeding unit in a state where the documents sent from the document bundle are easily separated.
[0015]
In addition, a document is called by the calling roller 3 from the document bundle 20 set so that the front end portion is positioned obliquely downward on the document table 1, and the uppermost document is inclined toward the paper feeding belt 4 and the reverse roller 6 at that time. Since it is bent upward, it is easy and reliable to further separate the document bundle 20, and stable pre-separation can be performed regardless of the number of documents.
[0016]
【The invention's effect】
According to the first aspect of the present invention, the front end portion of the document fed from the document bundle is bent from obliquely downward to obliquely upward between the document setting unit and the separation feeding unit. By providing pre-separating means that facilitates separation, it is possible to improve the separation of the original bundle.
[0017]
Further, the document setting unit tilts the document so that the leading end is positioned downward, and the pre-separating unit guides the leading end portion of the document bundle between the sending unit and the separation sheet feeding unit, and the sending unit. The pre-separating means has a simple structure by having a bending guide part at the center of the pre-separating direction in the pre-separating means for bending the uppermost document obliquely upward toward the separating and feeding part in cooperation with the part. The pre-separation means can be realized at low cost.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of an automatic document feeder according to an embodiment of the present invention.
FIG. 2 is a diagram showing a main configuration of an automatic document feeder according to an embodiment of the present invention.
FIG. 3 is a diagram showing a state when a document bundle 20 is sent out by a call roller 3 in the automatic document feeder according to the embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Document table 2 Document stop nail 3 Calling roller 4 Paper feed belt 5 Pull-out roller 6 Reverse roller 7 Transport belt 8 Contact glass 9 Switching claw 10 Paper discharge tray 11 Reverse paper discharge roller 12 Reverse paper discharge roller pair 13 Paper feed port 14 Roll Pair 15 Roller pair 18 Pull-out sensor 19 Registration sensor 20 Document bundle 21 Document 30 Guide plate 31 Depression 32 Down slope 33 Up slope

Claims (1)

A document setting unit for setting a document bundle, a sending unit for sending a document from the set document bundle, a separation feeding unit for separating the top document from the sent documents from the other and feeding it to a predetermined position; In an automatic document feeder provided with
Pre-separating means for facilitating the separation by bending the leading edge of the document sent from the document bundle from obliquely downward to obliquely upward is provided between the document setting unit and the separation and feeding unit. ,
The document setting unit inclines the document so that the leading end is positioned downward, and the pre-separating unit guides the leading end of the document bundle between the sending unit and the separation feeding unit, and the sending unit. A depression, which is a bending guide portion that cooperates to bend the uppermost document obliquely upward toward the separation sheet feeding portion, and forms a depression in the document feeding direction in the pre-separating means and a nip portion of the separation sheet feeding portion. An automatic document feeder characterized by having it at the center of the document.

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