JP3457121B2 - Automatic document feeder - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic document feeder mounted on an image reading device such as a copying machine, a facsimile device, a scanner device or the like, and more specifically, a document from a stack of documents placed on a document table. The present invention relates to an automatic document feeder that can separate sheets one by one and convey them toward a reading position.

[0002]

2. Description of the Related Art Conventionally, in an image reading apparatus such as a copying machine, a facsimile apparatus, a scanner apparatus, etc., when a document stack consisting of a plurality of documents is placed on a document table and a job start switch is depressed, The sheets are separated one by one and conveyed to the reading position, and the original is read by the image reading means of the image reading device at the reading position. When the reading is completed, the original is discharged to a predetermined discharging position. Some automatic document feeders are provided, and as such an automatic document feeder, for example, the one described in JP-A-6-92482 is known.

This is a document placing table on which a document bundle consisting of a plurality of documents can be placed, and a document placing table which is arranged substantially in the center in the width direction of the document and which is placed above the document placing table. A calling roller that feeds the positioned originals, and a pressure plate that is provided so as to come into contact with and separate from the calling rollers from below and that extends in the width direction of the originals to press the original stack toward the calling rollers. , Which extends between the calling roller and the reading position, and which is provided on the downstream side of the conveying direction of the calling roller and the conveying path including the outer guide and the inner guide, and is located at the highest position from the original fed by the calling roller. A feed belt that can move in the direction of separating the documents and a reverse roller that moves in the direction of preventing separation of the remaining documents,
It is provided on the upstream side of the reverse roller in the document transport direction and extends on the same line across the width of the document, preventing the document stack from entering between the feed belt and the reverse roller by abutting the leading edge of the document stack. Stopper member to
Is equipped with.

In such an automatic document feeder,
When the document stack is placed on the document table and the start switch is pressed, the pressure plate presses the document stack against the calling roller, and the front end of the document stack is separated from the stopper member and can enter the feed belt and reverse roller. become. Next, when the calling roller is driven, the document bundle is conveyed toward the feed belt and the reverse roller.

After the uppermost original is separated by the feed belt and the reverse roller, the original bundle is conveyed toward the reading position through the conveying path defined by the outer guide and the inner guide, and stopped at the reading position. The sheet is discharged after being read by the image reading means.

[0006]

However, in such a conventional automatic document feeder, the document bundle pressed by the pressure plate to the calling roller is fed by the calling roller along the guide. Therefore, when the original is curled, the curled portion comes into contact with the guide to increase the conveyance resistance between the original and the guide, and the original is likely to be bent when the paper is fed by the calling roller. I have a problem.

Further, since the conveyance resistance between the document and the guide becomes large, when the document stack is pressed by the pressing plate against the calling roller, a slip occurs between the document and the calling roller, and the document is called. There was a problem that the non-feeding of the item would occur. In order to prevent such problems from occurring, when the pressure of the pressure plate is increased,
When a document without curl is fed, an excessive pressure is applied to the document, which causes a problem that a load is applied to the calling roller.

Further, since the stopper member extends on the same line in the width direction of the document, when the document is curled as described above, the curled portion may be caught by the stopper member. Yes, sometimes the manuscript was not sent. Therefore, according to the present invention, even when the original is curled, it is possible to prevent the conveyance resistance of the original from increasing and prevent the non-feeding from occurring, and the original is bent. It is an object of the present invention to provide an automatic document feeder that can prevent the occurrence of a sheet and stably feed the document.

[0009]

The invention according to claim 1 is
In order to solve the above problems, an automatic document feeder capable of separating documents one by one from a stack of documents placed on a document table and transporting them toward a reading position, the document being substantially central in the width direction. And a sheet feeding member for abutting the upper surface of the original stack placed on the original placing table to feed the original located above the original stack, and abutting and separating the sheet feeding member from below. A pressure plate that is provided so that it extends in the width direction of the document and that presses the document stack toward the paper feed member, and extends between the paper feed member and the reading position, and forms a part of the transport path. The constituent guides and a conveying member which is provided on the downstream side of the sheet feeding member in the document conveying direction and is movable in a direction of separating the uppermost document from the document fed by the sheet feeding member and the remaining document are separated. A separating member composed of a blocking member that moves in a blocking direction; A stopper member that is provided on the upstream side in the document conveying direction and that extends in the width direction of the document and that prevents the document stack from entering the separating means by contacting the leading end of the document stack. In the automatic document feeder, wherein the front end of the document bundle is separated from the stopper member and is allowed to enter between the separating member and the blocking member when the document bundle is pressed against the sheet feeding member by the pressure plate, the pressure plate and the stopper are provided. The member is characterized in that the central portion facing the sheet feeding member is projected and both ends are lowered in the direction away from the sheet feeding member.

In this case, since the central portion of the pressure plate facing the sheet feeding member is projected and both ends are lowered in the direction away from the sheet feeding member, if the original stack is curled, the curl occurs. The removed portion escapes to the pressure plate side, which is lowered in the direction away from the sheet feeding member. Therefore, even if the document slides on the guide, the conveyance resistance between the document and the guide does not increase, and the document is not bent when the sheet is fed by the sheet feeding member.

Further, since the conveyance resistance between the document and the guide does not become large, when the document stack is pressed against the sheet feeding member by the pressure plate, no slip occurs between the document and the sheet feeding member, and the document is not slipped. Does not occur. Further, since the central portion of the stopper member facing the paper feeding member is projected and both end sides are lowered in the direction of separating from the paper feeding member, no document misfeed occurs. As a result, the original can be stably fed.

Further, since it is only necessary to press the document bundle with a necessary minimum pressing force, it is possible to perform an economical design.
According to a second aspect of the present invention, in order to solve the above-mentioned problems, in the first aspect of the invention, an upstream side end portion of the guide in the conveying direction has a conveying surface located on both sides of the sheet feeding member. A portion of the transport surface close to the sheet feeding member is provided on substantially the same line as the outer peripheral end surface of the sheet feeding member, and the other portion is provided so as to be separated toward the outer peripheral end surface of the sheet feeding member. It has a feature.

In this case, since the gap between the pressure plate and the guide is further increased, it is possible to secure a larger escape portion for the curled portion of the document, and to further prevent the document from curving or not feeding. be able to.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 to 4 are views showing an embodiment of an automatic document feeder according to the present invention, showing an example in which the automatic document feeder is mounted on an image reading apparatus. The image reading device can be applied to a copying machine, a facsimile device, a scanner device and the like.

First, the structure will be described. In FIG. 1, 1
Is an image reading device, and a slit glass (reading position) 2 and a contact glass 3 are provided on the upper surface of the image reading device 1. An exposure lamp 4, a first mirror 5 and the like are provided below the slit glass 2 and the contact glass 3, and the exposure lamp 4 and the first mirror 5 are used for reading an original placed on the contact glass 3. 1 is moved below the contact glass 3 in the horizontal direction in FIG. 1, and when reading the original on the slit glass 2, the original is stopped below the slit glass 2 and the original surface is read by the exposure lamp 4. After that, this reflected light is focused on a focusing element such as a CCD through a first mirror 5 and a lens (not shown) as is known.

An automatic document feeder (hereinafter, simply referred to as an ADF) 6 is mounted on the upper portion of the image reading apparatus 1, and the original placed on the contact glass 3 is placed on the lower surface of the ADF 6 to the contact glass 3. A reflecting plate 7 is provided which is pressed against and serves as a white reference when reading a document.
The ADF 6 is connected to the image reading device 1 via a hinge (not shown) and can be opened and closed with respect to the image reading device 1.

Further, a document placing table 8 is provided on the upper part of the ADF 6, and a document bundle P made up of a plurality of documents is placed on the document placing table 8. The original bundle P placed on the original placing table 8 contacts the original bundle P.
After being fed by the detachable calling roller (paper feed member) 9, the separation belt (separation member) 10 and the separation prevention roller 11
The uppermost document is separated by the (blocking member), and the separation belt 10 presses and contacts the separation blocking roller 11 at an arbitrary angle.

A stopper member 12 is provided downstream of the calling roller 9 in the original conveying direction, and the leading end of the original bundle P placed on the original table 8 is stopped by the stopper member 12 to separate the belt. It is forbidden to enter between 10 and separation blocking roller 11. A pressure plate 13 is provided below the calling roller 9.
The pressurizing plate 13 is configured to come into contact with and separate from the calling roller 9 about a swing fulcrum by a solenoid (not shown). That is, when the copy start switch is pressed, the pressure plate 13 moves from the position separated from the calling roller 9 shown by the solid line by the solenoid to the position where it abuts the calling roller 9 shown by the phantom line around the swing fulcrum. Then, the originals are pressed against the calling rollers 9, and the leading end of the original bundle P is separated from the stopper member 12 so that the originals can enter between the separation belt 10 and the separation preventing rollers 11. It is designed to feed paper.

The document separated by the separation belt 10 and the separation prevention roller 11 is reversed along the conveyance path 17 by the first conveyance driving roller 14a and the driven roller 14b and conveyed toward the slit glass 2. ing. The conveying path 17 is constituted by an inner peripheral surface of a case 6a provided so as to be openable and closable with respect to the main body of the ADF 6, and an outer guide (guide) 17a extending between the calling roller 9 and the slit glass 2 and this case. It is defined by an inner guide 17b formed on the main body side of the ADF 6 facing the 6a.

Further, the first transport driving roller 14a and the driven roller 14b sandwich the separated document, transport it to the slit glass 2 through the transport path 17, and then pick it up to the paper discharge path 20 by the reverse paper discharge guide 23. It is designed to be transported. A reflection guide plate 18 is provided on the slit glass 2, and this reflection guide plate 18 constitutes a white reference at the time of reading.

The document conveyed to the sheet discharge path 20 is nipped by the second conveying drive roller 19a and the driven roller 19b on the driving side and conveyed, and then is sandwiched by the sheet discharge driving roller 21a and the driven roller 21b. The sheet is discharged from the sheet discharge path 20 to the outer cover 22. On the other hand, the reflector 7 that covers the contact glass 3
Is provided on the lower surface of the pressure plate 24, and the pressure plate 24 presses the original placed on the contact glass 3 against the glass 3.

The pressure plate 24 is rotatably attached to a main frame 26 via a fulcrum 25. The main frame 26 has an end portion attached to the shaft of the driven roller 21b, and the ADF
6 Fixed to the body. Further, the main frame 26 has an area that covers the contact glass 3, and the outer cover 22 is attached to the upper surface thereof, and together with the outer cover 22, constitutes a document discharge tray. The pressure plate 24 is connected to an auxiliary frame 28 via a link 29. The auxiliary frame 28 is formed in a substantially U-shaped cross section so as to sandwich the outer peripheral portion of the main frame 26, and a fulcrum 27 is interposed therebetween. Is rotatably connected to the main frame 26.

The main frame 26 also has a magnet 30.
The magnet 30 is attached to the auxiliary frame 28.
Is sucking. The auxiliary frame 28 may be entirely made of metal, or may be entirely made of an elastic member such as plastic and only the portion attracted by the magnet 30 may be made of metal. The auxiliary frame 28 has a tip portion (the left end portion in FIG. 1) that constitutes a part of the paper discharge path 20, and a driven roller 19b is rotatably provided at the tip portion.

On the other hand, as shown in FIGS. 2 and 3, the calling roller 9 and the separation preventing roller 11 are arranged substantially in the central portion in the width direction of the document, and the axial length thereof is formed shorter than the width of the B5 vertical document. ing. Further, in the pressure plate 13, a central portion 13a facing the calling roller 9 is projected, and both end sides 13b are lowered in a direction separating from the calling roller 9, and a step H ₁ is formed between the central portion 13a and both end portions 13b. Is provided.

Further, the stopper member 12 is a calling roller 9
The central portion 12a facing to the
Is lower in the direction away from the calling roller 9, and a step H ₂ is provided at the central portion 12a and both end portions 12b. At the upstream end of the outer guide 17a in the document transport direction, the transport surface is located on both sides of the calling roller 9, and the portion of the transport surface near the calling roller 9 (hereinafter referred to as the central portion 31).
Is located substantially on the same line as the outer peripheral end surface of the calling roller 9, and the other portions (hereinafter, both ends 32) are separated toward the outer peripheral end surface of the calling roller 9. The central portion 31 and end portions 32 has a step H _3.

Next, the operation will be described. When the document stack P is placed on the document mounting table 8 with the document surface facing upward and the start switch is pressed, the pressure plate 13 presses the document stack P against the calling roller 9 to cause the leading end of the document stack P. Is separated from the stopper member 12 so that it can enter between the separation belt 10 and the separation prevention roller 11. Then, by driving the calling roller 9, the upper portion of the document stack P is conveyed between the separation belt 10 and the separation prevention roller 11.

In this document bundle P, after the uppermost document is separated by the separation belt 10 and the separation prevention roller 11, the first conveyance driving roller 14a and the driven roller 14b move on the slit glass 2 along the conveyance path 17. After being transported to
The original surface is read by the exposure lamp 4, the first mirror 5, and the like on the slit glass 2. The read document is conveyed on the conveyance path 20 by the second conveyance driving roller 19a and the driven roller 19b, and then ejected onto the outer cover 22 by the paper ejection driving roller 21a and the driven roller 21b.

By the way, when the original bundle P placed on the original placing table 8 is curled by H ₄ as shown in FIG. 2, the outer guide A of the calling roller 9 is indicated by the one-dot chain line. In the conventional case that extends on the same flat line as the lower end surface, the curled portion overlaps the inner guide A by ΔH, and a large conveyance resistance between the document and the outer guide A is caused by this amount. Occurs, the original is bent when the paper is fed by the calling roller 9, or the original and the calling roller 9
There was a problem that a slip occurred during the interval and the document was not fed.

In this embodiment, the central portion 13a of the pressure plate 13 which faces the calling roller 9 is projected, and both end sides 13b are formed.
Lower in the direction away from the calling roller 9
A step H ₁ is provided on 13a and both end portions 13b, and the central portion 31 of the conveying surface of the outer guide 17a is positioned substantially on the same line as the outer peripheral one end surface of the calling roller 9, and both end portions 32 of the calling roller 9 are positioned. Center part 31
Since the step H ₃ is provided at both ends 32, the original overlap ΔH can be released by the step H ₁ or H ₃ . Therefore, the conveyance resistance between the document and the outer guide 17a does not increase, and the document is not bent when the sheet is fed by the calling roller 9.

Further, since the conveyance resistance between the document and the outer guide 17a does not increase, when the document stack P is pressed against the calling roller 9 by the pressure plate 13, a slip may occur between the document and the calling roller 9. There is no problem, and there is no possibility that the document will not be fed. On the other hand, at the time of paper feeding by the calling roller 9,
If the stopper member extends on the same line across the width of the document as in the past, the curled portion abuts the stopper member and the document is not fed. in the example, provided with a step H ₃ in the outer guide 17a, are made to protrude from the central portion 12a which faces the pickup roller 9 of the stopper member 12, constitute low in the direction of separating the both ends 12b from pickup roller 9, the central portion Since the step H ₂ is provided on the 12a and the both end portions 12b, it is possible to prevent the curled portion from being caught by the stopper member 12 and prevent the document from not being fed. As a result, in this embodiment, the original can be stably fed.

Further, in this embodiment, since it is not necessary to increase the pressure applied by the pressure plate as in the conventional case, it is possible to obtain an effect that an economical design can be performed. In this embodiment, the step H ₃ is provided on the outer guide 17a, but the guide plate H ₃ may be left as it is and the pressure plate 13 and the stopper member 12 may be provided with the steps H ₁ and H _2. .

In this case, the original is curled H
_{When 4} occurs, the above-described overlap ΔH can be released to both end portions 13b of the pressure plate 13, and the conveyance resistance between the original and the outer guide 17a becomes large even if the original slides on the outer guide 17a. It is possible to prevent the occurrence of document bending at the time of feeding by the call roller 9 and the occurrence of slip between the document and the call roller 9 to prevent the document from not being fed. it can.

Further, the overlapping portion .DELTA.H at both ends 12b of the stopper member 12 is not caught, and the non-feeding of the original can be prevented. Further, in the case where the step H ₃ is not provided on the outer guide 17a as described above, if the relationship between ΔH, H ₁ and H ₂ is set to ΔH <H ₁ <H ₂ , then both end portions 32 of the stopper member 12 are provided. It is possible to reliably prevent the overlapped portion ΔH from being caught.

As described above, steps H ₁ , H ₂ and H ₃ are formed on the pressure plate 13, the stopper member 12 and the outer guide 17a.
In the case where the sheet is provided, the gap between the pressure plate 13 and the outer guide 17a can be made even larger, so that it is possible to secure a larger escape portion for the curled portion of the document, and it is possible to prevent the document from bending or not feeding. Needless to say, it is possible to further prevent the occurrence of.

[0035]

According to the first aspect of the present invention, when the original bundle is curled, the curled portion can be released to the side of the pressure plate which is lowered in the direction of separating from the sheet feeding member. . Therefore, it is possible to prevent the conveyance resistance between the document and the guide from increasing even when the document slides on the guide, and it is possible to prevent the document from bending when the document is fed by the sheet feeding member.

Further, since the conveyance resistance between the document and the guide does not become large, it is possible to prevent the occurrence of slip between the document and the paper feed member when the document stack is pressed against the paper feed member by the pressure plate. Therefore, it is possible to prevent the document from not being fed. Also, it is possible to prevent the document from being caught on both ends of the stopper member at the time of feeding,
It is possible to prevent the document from being unfed. As a result, the original can be stably fed. Further, since it is only necessary to press the document stack with the necessary minimum pressing force, it is possible to perform an economical design.

According to the second aspect of the present invention, since the gap between the pressure plate and the guide can be further increased, it is possible to secure a larger escape portion for the curled portion of the document and to bend the document. It is possible to further prevent the occurrence of non-feeding.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an embodiment of an automatic document feeder according to the present invention.

FIG. 2 is a perspective view of a separation preventing roller, a pressure plate, a stopper member, and a document according to an embodiment.

FIG. 3 shows a calling roller, an outer guide, a pressure plate,
FIG. 6 is a schematic view showing a positional relationship between a stopper member, separation preventing rollers, and a document.

[Explanation of symbols]

1 Image reading device 2 Slit glass (reading position) 6 ADF (Automatic Document Feeder) 8 Document holder 9 Calling roller (paper feed member) 10 Separation belt (separation member) 11 Separation blocking roller (blocking member) 12 Stopper member 12a Central part 12b both ends 13 Pressure plate 13a central part 13b Both ends 17 Transport path 17a Outside guide 31 Central part 32 both ends P original bundle

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B65H 1/14 310 B65H 3/56 330 G03G 15/00 107 H04N 1/00 108

Claims (2)

(57) [Claims] 1. An automatic document feeder that separates documents one by one from a document stack placed on a document table and conveys the documents toward a reading position, the device being provided at a substantially central portion in the width direction of the documents. And a paper feed member that comes into contact with the upper surface of the original stack placed on the original table and feeds the original document located above the original stack, and is provided so as to be in contact with and separated from the paper feed member from below. A guide plate that extends between the paper feed member and the reading position, and a pressure plate that extends across the width of the document and presses the document stack toward the paper feed member, and forms a part of the transport path. And a conveying member which is provided on the downstream side of the sheet feeding member in the document conveying direction and is movable in a direction for separating the uppermost document from the document fed by the sheet feeding member and a direction for preventing separation of the remaining document. And a separating member including a blocking member that moves to A stopper member that is provided on the upstream side in the direction of the document and that extends in the width direction of the document, and that abuts against the leading end of the document stack to prevent the document stack from entering the separating means. In an automatic document feeder in which a front end portion of a document bundle is separated from a stopper member and is allowed to enter between a separating member and a blocking member when the bundle is pressed by a sheet feeding member, the pressure plate and the stopper member are An automatic document feeder, wherein a central portion facing the sheet feeding member projects and both ends are lowered in a direction away from the sheet feeding member. 2. The upstream end portion of the guide in the conveying direction of the document has a conveying surface located on both sides of the paper feeding member, and a portion of the conveying surface near the paper feeding member is an outer peripheral end surface of the paper feeding member. 2. The automatic document feeder according to claim 1, wherein the automatic document feeder is provided on substantially the same line, and the other portions are provided so as to be separated toward the other end surface of the outer periphery of the sheet feeding member.