JPH09202490A - Automatic original carrying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic original carrying device which is compact, light in weight, being inexpensive, and capable of preventing occurrence of the defective reading and elongation of the image due to the incorrect carriage during the reading. SOLUTION: An automatic original carrying device comprises a curved part 17a which carries an original separated by a pair of carrying rollers 14 to a slit glass 2 and curves an inner guide plate 17 so that a center part opposite to the extension direction of a separation belt 10, a separation roller 11 and a pair of carrying rollers 14 is projected toward an outer guide plate 16, and a flat part 17b of flat shape which is formed on each side of the curved part 17 and arranged on the line to connect a nip part of the separation belt 10 and the separation roller 11 to a nip part of the carrying rollers 14.

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 or a facsimile device, and more specifically, it separates one document from a plurality of document bundles at a reading position. The present invention relates to an automatic document feeder that conveys an image to a stopped image reading unit.

[0002]

2. Description of the Related Art Conventionally, in an image reading apparatus such as a copying machine, when a document bundle consisting of a plurality of documents is placed on a document table and a copy is instructed, the documents are separated and read one by one. Some automatic document feeders are configured to discharge a document to a predetermined discharge position when the document is read by the image reading unit that is transported to the position and stopped at the reading position. As a document feeder, for example, one described in Japanese Utility Model Laid-Open No. 3-23137 is known.

In this document, a document placing table on which a document bundle consisting of a plurality of documents can be placed, and one document is separated from the document set placed on the document placing table, and the separated documents are inverted. A separation belt that is conveyed toward the reading position through the conveyance path, a separation roller that is in sliding contact with the separation belt, and two pairs of conveyance rollers that are provided on the conveyance path and that sandwich the document and convey the document to the reading position. .

In this automatic document feeder, the document placed on the document placing section is inverted and conveyed to the reading position. Therefore, the conveying path defines the conveying path of the original, and the reading surface is formed when the original is conveyed. The outer guide plate and the inner guide plate opposite to the reading surface face each other, and both guide plates are formed in the same curved shape.

[0005]

However, in such a conventional automatic document feeder, since the two pairs of transport rollers are provided, the cost of the apparatus increases and the pair of transport rollers are installed. There has been a problem that the space is increased, the device is enlarged, and the weight of the device is increased.

Further, the document conveyed to the reading position has a curved conveying path which is composed of an outer guide plate whose reading surface faces and an inner guide plate whose surface opposite to the reading face faces. Since the document is guided, the back surface of the document is rubbed by the inner guide plate, and the conveyance resistance increases. In addition to this, the relationship between the feed speed V1 of the separation belt and the feed speed V2 of the two conveying roller pairs is preferably V1 = V2. However, the feed speed V1 of the separation belt and the feed speed V1 'of the original are determined by the slip of the separation belt. Since V1> V1 'may occur, the document feed speed V1' becomes V2> V1 'with respect to the feed speed V2 of the transport roller pair, and the document is pulled by the transport roller pair. For this reason, as described above, the predetermined conveyance speed cannot be obtained due to the increase in the conveyance resistance due to the slip and the inner guide plate, and the image is stretched when the document is read.

Further, since the inner guide plate extends in the width direction of the document and the extending directions of the separation belt and the conveying roller pair are shorter than the extending direction of the inner guide plate, the slip and the inner guide described above are formed. There is a problem that the original is bent due to an increase in conveyance resistance due to the plate, and reading failure occurs. Therefore, the invention of claim 1 is
It is an object of the present invention to provide an automatic document feeder which is small in size, light in weight, low in cost, and capable of preventing reading defects and image stretching due to conveyance bending during reading.

[0008]

According to the first aspect of the present invention,
In order to solve the above-mentioned problems, an automatic document feeder mounted on an image reading device having an image reading means capable of reading a document by stopping at the reading position, wherein the image is fed while the document is being conveyed to the reading position. In an automatic document feeder configured to read a document by a reading unit, a document placing table on which a document bundle consisting of a plurality of documents can be placed, and one document from the document bundle placed on the document placing table A separating member that separates the originals and conveys the separated originals to the reading position through a conveying path; and a pair of conveying rollers that is provided on the conveying path and that nips the originals and conveys them to the reading position. And the inner guide plate includes an outer guide plate that defines a document feed path and has a reading surface that faces the reading surface when the document is fed, and an inner guide plate that faces the reading surface. , Separation The center portion of the material and the pair of conveying rollers facing each other in the extending direction is formed of a curved portion curved so as to project toward the outer guide plate, and flat portions formed on both sides of the curved portion and having a planar shape. I am trying.

In this case, since the document separated by one pair of transport rollers is transported to the reading position, the cost of the apparatus is reduced, the installation space for the pair of transport rollers is reduced, and the apparatus is downsized. Moreover, the weight of the device is reduced. In addition, the inner guide plate is formed on both sides of the curved portion and the curved portion that is curved so that the central portions of the separating member and the pair of conveying rollers that face each other in the extending direction project toward the outer guide plate, and have a planar shape. Since it is composed of the flat portion, the central portion of the back surface of the original can be brought into sliding contact with only the curved portion of the inner guide plate, and the conveyance resistance of the original can be significantly reduced. Therefore, even if a slip occurs between the separation member and the document, the slip between the pair of transport rollers and the document can be reduced, and it is possible to prevent the image from being stretched when the document is read.

Further, since the curved portions of the inner guide plate are opposed to each other in the extending directions of the separating member and the pair of conveying rollers, the conveying resistance with respect to the original can be made uniform and the original is bent. It is possible to prevent the reading failure of the document from occurring.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 are views showing an embodiment of an automatic document feeder according to the present invention, and show an example in which the automatic document feeder is mounted on an image reading apparatus such as a copying machine. First, the configuration will be described. In FIG. 1, reference numeral 1 denotes a copying machine as an image reading apparatus, and a slit glass (reading position) 2 and a contact glass 3 are provided on the upper surface of the copying machine 1.

Below the slit glass 2 and the contact glass 3, there are an exposure lamp 4 as an image reading means and a first lamp.
A mirror 5 and the like are provided. The lamp 4 and the first mirror 5 move below the contact glass 3 in the left-right direction in FIG. 1 when reading an original placed on the contact glass 3. Further, when reading a document on the slit glass 2, the document is stopped below the slit glass 2 and the exposure lamp 4
After exposing the original surface by the CCD, the reflected light is transmitted through the first mirror 5 and a lens (not shown) to the CCD as is known.
The image is formed.

An automatic document feeder (hereinafter, simply referred to as ADF) 6 is mounted on the upper portion of the copying machine 1, and the document placed on the contact glass 3 is placed on the contact glass 3 on the lower surface of the ADF 6. A reflecting plate 7 is provided which serves as a white reference when the original is read while being pressed, and can be opened and closed with respect to the copying machine 1. Further, a document placing table 8 is provided on the upper part of the ADF 6, and a document stack P made up of a plurality of documents is placed on the document placing table 8. The original stack P placed on the original placing table 8 is fed by a calling roller 9 which can be brought into contact with and separated from the original stack P, and then separated by a separation belt 10 and a separation roller 11. There is.

Further, a stopper member 12 is provided downstream of the calling roller 9 in the original conveying direction, and the original bundle P placed on the original placing table 8 is urged against the stopper member 12 to the separating belt 10 side. It is forbidden to enter. A pressing plate 13 is provided below the calling roller 9, and the pressing plate 13 is brought into contact with and separated from the calling roller 9 by a solenoid (not shown). That is, when the copy start switch is pressed, the pressing plate 13 is moved by the solenoid from the position separated from the calling roller 9 shown by the solid line to the position where it comes into contact with the calling roller 9 shown by the phantom line to read the original. The roller 9 is pressurized and the original is fed by the calling roller 9.

The separating belt 10 moves clockwise and the separating roller 11 rotates clockwise, so that the uppermost original is separated from the original stack P fed by the calling roller 9. It is like this. The separation belt 10 and the separation roller 11 form a separation member. The separated document is sandwiched by a pair of transport rollers 14 composed of a transport driving roller 14a and a transport driven roller 14b and transported along a transport path 15. The transport path 15 reverses the original. The slit glass 2 is conveyed.

The conveyance path 15 is composed of an outer guide plate 16 that defines a document conveyance path and has a reading surface facing the reading surface when the document is conveyed, and an inner guide plate 17 that faces the reading surface opposite to the reading surface. As shown in FIG. 2, the inner guide plate 17 has a central portion opposed to each other in the extending direction of the separation belt 10, the separation roller 11, and the conveyance roller pair 14 (only the conveyance driving roller 14a is shown in FIG. 2). The curved portion 17a is curved so as to project toward the outer guide plate 16 and the flat portions 17b formed on both sides of the curved portion 17a and having a planar shape.
Further, the flat surface portion 17b is arranged on a line (indicated by an imaginary line F) connecting the tangents of the separation belt 10 and the nip portion of the separation roller 11 and the nip portion of the transport roller pair 14. The outer guide plate 16
Is formed in the same shape as the curved portion 17a across the width of the inner guide plate 17.

A reflection guide plate 18 is provided above the slit glass 2, and this reflection guide plate 18 constitutes a white reference at the time of reading. Further, a conveyance roller pair 19 including a conveyance driving roller 19a and a conveyance driven roller 19b is provided downstream of the slit glass 2 in the original conveyance direction, and the conveyance roller pair 19 ejects the original document read by the slit glass 2. The paper is conveyed through the paper path 20 toward a paper discharge roller pair 21 including a paper discharge driving roller 21a and a paper discharge driven roller 21b.

This paper discharge roller pair 21 is a ADF main body 6 on the contact glass 3 for the document conveyed by the conveyance roller pair 19.
The part is protected, and the document is discharged onto the protective cover 22 which constitutes the document discharge part. Further, a scale 23 is provided between the slit glass 2 and the contact glass 3, and this scale 23 is a reading reference position with which the edge of the original comes into contact when the original is placed on the contact glass 3 and read. In addition, when the document is read by the slit glass 2, the document that has passed over the slit glass 2 is scooped up to the paper discharge path 20.

The reflector 7 is attached to the lower portion of the protective member 24, and the protective member 24 is connected to the ADF 6 via a fulcrum 25.
It is rotatably provided on the main body. Further, a paper discharge frame 26 is rotatably provided at the fulcrum 25, and a paper discharge driven roller 21b is attached to the paper discharge frame 26. A transport driven roller holding member 28 is rotatably attached to the paper discharge frame 26 via a fulcrum 27, and a transport driven roller 19b is attached to the transport driven roller holding member 28.

Further, the holding member 24 and the transport driven roller holding member
The links 28 are connected by a link 29, and the transport driven roller holding member 28 abuts and separates from the holding member 24 via the link 29. A magnet 30 is attached to the paper discharge frame 26, and the magnet 30 attracts the transport driven roller holding member 28. In addition,
The transport driven roller holding member 28 may be entirely made of metal because it is attracted by the magnet 30, or may be made of plastic or the like and only the attracting portion may be made of metal.

In these members on the contact glass 3, by rotating the paper discharge frame 26 upward through the fulcrum 25, the transport driven roller 19b and the paper discharge driven roller 21 are moved.
b is separated from the conveyance driving roller 19a and the paper ejection driving roller 21a to open the conveyance path 20 and the jammed document on the conveyance path 20 can be removed. The protective cover 22 covers the paper discharge frame 26.

Next, the operation will be described. When a document stack P composed of a plurality of double-sided documents is placed on the document mounting table 8 and the start switch is pressed, the pressure plate 13 calls the document stack P on the roller 9.
By pressing, the bundle of documents is conveyed toward the separation belt 10 by the calling roller 9. This original is separated from the uppermost original by a separation belt 10 and a separation roller 11, and then is conveyed onto a slit glass 2 along a conveyance path 15 by a conveyance roller pair 14, and then an exposure lamp is used by the slit glass 2. The document surface is read by the fourth mirror 5, the first mirror 5, and the like. The document that has been read is transported on the transport path 20 by the transport roller pair 19, and then discharged onto the protective cover 22 by the paper discharge roller pair 21.

Although the present embodiment is characterized by the structure of the conveying path 15, one conveying roller pair will be described before the explanation.
14 will be used to describe a conventional method of conveying a document along a curved conveyance path. Normally, the relationship between the feed speed V1 of the separation belt 10 and the feed speed of the transport driving roller 14a is V1 = V
Although it is preferable that the speed is 2, the speed V1 of the separation belt 10 and the document feed speed V1 'may become V1>V2' due to slip. Feed rate V1 'is V2>V1'
Therefore, the document is pulled by the pair of transport rollers 14.

FIG. 3 shows the state of conveyance of the original P1 when there is no curved inner guide plate as in the conventional case. In this case, the original P1 is pulled on the straight line connecting the tangents of the separating belt 10 and the nip portion of the separating roller 11 and the nip portion of the conveying roller pair 14, but in reality, the separating belt 10 is pulled.
Since there are inner and outer guide plates between the pair of transport rollers and the transport roller pair 14, the document P1 has a large transport resistance to the inner guide plate. As a result, the slip ratio between the pair of transport rollers 14 also increases, and the original P1 cannot be transported at a predetermined transport speed.

Therefore, in the present embodiment, the inner guide plate 17
Are formed on both sides of the curved portion 17a and the curved portion 17 that are curved so that the central portions of the separation belt 10, the separation roller 11, and the conveyance roller pair 14 that face each other in the extending direction project toward the outer guide plate 16. Since the separation belt 10 and the separation roller 11 and the nip portion of the conveyance roller pair 14 are formed on the line connecting the tangents of the nip portion of the conveyance roller pair 14 and have a plane shape, the document is curved 17a. The original can be smoothly conveyed to the nip portion of the conveying roller pair 14 via the conveying path defined between the outer guide plate 16 and the outer guide plate 16, and the central portion of the back surface of the original is slidably contacted only with the curved portion 17a. It is possible to significantly reduce the transport resistance of the.

Therefore, even if a slip occurs between the separation belt 10, the separation roller 11 and the original document, the conveyance roller pair 14
It is possible to reduce the slip between the original and the original, and it is possible to prevent the image from being stretched when the original is read. Further, since the curved portion 17a is opposed to the separating belt 10, the separating roller 11 and the conveying roller pair 14 in the extending direction, the contact resistance with respect to the document can be made uniform and the document bending can be prevented. Thus, it is possible to prevent the reading failure of the document.

Further, since the document separated by one pair of transport rollers 14 is transported to the slit glass 2,
It is possible to reduce the cost of the DF 6, reduce the installation space of the transport roller pair 14, reduce the size of the ADF 6, and further reduce the weight of the ADF 6. In this embodiment, the flat surface portion 17b is arranged on the line connecting the tangent lines of the separation belt 10, the nip portion of the separation roller 11 and the nip portion of the conveying roller pair 14, but at a position other than this line. You may arrange.

[0028]

According to the first aspect of the invention, since the original separated by one pair of conveying rollers is conveyed to the reading position, the cost of the apparatus can be reduced and the pair of conveying rollers can be used. The installation space can be reduced, the device can be downsized, and the weight of the device can be reduced.

Further, the inner guide plates are formed on both sides of the curved portion and the curved portion which are curved so that the central portions of the separating member and the pair of conveying rollers facing each other in the extending direction project toward the outer guide plate. Since it is composed of a flat surface portion having a flat shape, the central portion of the back surface of the original can be brought into sliding contact with only the curved portion of the inner guide plate, and the conveyance resistance of the original can be greatly reduced. Therefore, even if a slip occurs between the separation member and the document, the slip between the pair of transport rollers and the document can be reduced, and it is possible to prevent the image from being stretched when the document is read.

Further, since the curved portions of the inner guide plate are opposed to each other in the extending direction of the separating member and the pair of conveying rollers,
The conveyance resistance with respect to the document can be made uniform, the document bending can be prevented from occurring, and the document reading failure can be prevented from occurring.

[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 configuration diagram of a calling roller, a separation belt, a separation roller, a conveyance roller pair, and an inner guide plate portion.

FIG. 3 is a diagram illustrating a document conveyance state when a guide plate is not present.

[Explanation of symbols]

 1 Copier (image reading device) 2 Slit glass (reading position) 4 Exposure lamp (image reading means) 5 First mirror (image reading means) 6 ADF (automatic document feeder) 8 Document tray 14 Transport roller pair 15 Transport Path 16 Outer guide plate 17 Inner guide plate 17a Curved part 17b Flat part

Claims (1)

[Claims] 1. An automatic document feeder mounted on an image reading device having an image reading means capable of reading a document while stopped at the reading position, wherein the image reading means transports the document to the reading position. In an automatic document feeder configured to read a document, a document table on which a document stack made up of a plurality of documents can be placed, and a document set placed on the document table are separated one by one. A separation member that conveys the separated document toward the reading position through a conveyance path that inverts the separated document; and one conveyance roller pair that is provided on the conveyance path and that nips the document and conveys the document to the reading position. The conveyance path includes an outer guide plate that defines a conveyance path for a document and has a reading surface that faces when the document is conveyed, and an inner guide plate that faces a surface opposite to the reading surface. The inner guide plate is a separating member. and It is characterized in that a central portion of each of the pair of feeding rollers facing each other in the extending direction is formed of a curved portion that is curved so as to project toward the outer guide plate, and flat portions that are formed on both sides of the curved portion and have a planar shape. Automatic document feeder.