JP2000128401A - Automatic document carrying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep carrying force constant applied to the width direction of each document regardless of its size, and to enhance the carrying performance of documents by preventing documents from skewing in returning each document back to constant glass. SOLUTION: A reference turn-over driving roller 22 and discharging driven roller are disposed so as to slidably come into contact with one end face in the width direction of documents of all sizes at all times, and the plural turn- over rollers 22 and the discharging driven rollers are disposed so as to slidably come into contact with the other end face in the width direction of each size document. When a document is to be returned back to a contact glass 2 with an end face reference of each document, any one of the discharging driven rollers located at a position corresponding to the size of a document to be returned to the contact glass 2, is slidably brought into contact with the turn- over driving roller 22.

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 apparatus such as a copying machine, a facsimile machine, a scanner, and the like. By turning over the completed manuscript on the contact glass and returning it,
The present invention relates to an automatic document feeder capable of reading the back side of a document.

[0002]

2. Description of the Related Art Generally, an automatic document feeder (hereinafter, referred to as a copier, facsimile, scanner, etc.)
In order to speed up or automate the reading of a document, the document is separated one by one from a bundle of documents placed on a document tray and transported to a reading position of a contact glass. The document which has been read is discharged onto the discharge tray.

An ADF for transporting an original to such a contact glass is provided with a transport belt on the upper surface of the contact glass. The original is transported to the reading position. In the double-sided reading mode, after the document is unloaded from the contact glass by the transport belt, a plurality of driving rollers and a plurality of driving rollers are provided downstream of the contact glass in the document transport direction and separated in the width direction of the document. The document is reversed by a plurality of driven rollers that slide against the rollers and returned to the contact glass. When the leading edge of the document reaches an arbitrary position on the reversing path, the transport belt is driven to rotate in reverse to discharge the paper. The document returned from the member is transported again to the reading position of the contact glass to read the back side of the document (for example, see Japanese Patent Application Laid-Open No. 4-257874).

When the original is transported to the contact glass and stopped, the leading end of the original in the transport direction is positioned at the reading position on the contact glass, or the original is transported to the reference scale provided at the end of the contact glass. There is a device that conveys and positions the document until the end portion in the direction abuts (so-called abutting), and the stop position is arbitrarily set by the ADF.

[0005]

However, in such a conventional ADF, a document is returned to a contact glass with reference to an end face in the width direction of the document. Since the driving roller and the driven roller are not arranged at an optimal position according to the size of the document and separated from one end surface in the width direction of the document (the end surface reference side), the center of the document in the conveyance direction may be dependent on the size of the document. The drive roller and the driven roller were not arranged at a fixed position on the line.

For this reason, there has been a problem that the conveyance force applied to the document by the conveyance load due to the driving roller and the driven roller at the time of reversing is not uniform in the width direction of the document, and skew occurs in the document. ADF with reference scale
Is to hit the original against the reference scale to prevent skew.However, if the skew that occurs when returning the original to the contact glass is large as described above, It cannot be completely corrected.

According to the present invention, when a document is returned to the contact glass, the conveying force applied in the width direction of the document can be kept constant regardless of the size of the document, and the skew of the document can be prevented. It is an object of the present invention to provide an automatic document feeder capable of improving the document transfer performance.

[0008]

According to the first aspect of the present invention,
In order to solve the above-mentioned problem, a separation sheet feeding unit that separates documents one by one from a bundle of documents placed on a document table and feeds the documents toward a contact glass is provided on an upper surface of the contact glass; Transport belt means for transporting the document fed by the separation paper feed means to a reading position on the contact glass, and carrying out the document which has been read at the reading position from the contact glass; and A reversing sheet discharging means for discharging the document conveyed out of the glass onto a discharge tray, or reversing on a reversing path and returning it to the contact glass; A document detecting means for detecting a size of the document, wherein the document is returned to the contact glass with reference to one end surface in the width direction of the document. An automatic document feeder configured to convey or return the document to a source glass, wherein the reverse discharge means includes a plurality of drive rollers disposed at a distance in the width direction of the document and for returning the document toward the contact glass. In the automatic document feeder having a plurality of driven rollers provided for each of the driving rollers and slidably in contact with the driving rollers, the driving rollers and the driven rollers abut on one end surfaces in the width direction of the originals of all sizes. And a plurality of reference driving rollers and reference driven rollers which are always in sliding contact with each other, and a plurality of positions which are arranged at positions corresponding to originals of various sizes and which are in contact with the other end surfaces in the width direction of the originals of various sizes. And a plurality of driven rollers provided slidably in contact with and separated from the driving roller, and one of the plurality of driven rollers is set to the driven roller based on detection information of the document detecting means. To It is characterized in that a driven roller control means for sliding contact with the drive roller to respond.

In this case, the reference drive roller and the driven drive roller are arranged so as to always contact one end in the width direction of the originals of all sizes, and the other end in the width direction of the originals of various sizes. A plurality of driving rollers and driven rollers are disposed so as to be separated from each other, and when returning an original to the contact glass on the basis of the end surface, the driven rollers positioned at positions corresponding to the size of the original to be returned to the contact glass are driven. , The drive roller and the driven roller, the reference drive roller and the reference driven roller hold the both end surfaces of the document, and the document is returned to the contact glass.

Therefore, the conveying force applied in the width direction of the original can be kept constant regardless of the size of the original, and the skew of the original can be prevented, thereby improving the original conveying performance. .

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 8 show an embodiment of the automatic document feeder according to the present invention, and show an example in which the automatic document feeder of the present invention is mounted on a copying machine as an image reading device. The image reading device can be applied to a facsimile device, a scanner device, and the like in addition to the copying machine.

First, the configuration will be described. 1 and 2, reference numeral 1 denotes a copying machine, and a contact glass 2 is provided on an upper surface of the copying machine 1. An automatic document feeder (hereinafter, simply referred to as an ADF) 3 is provided at an upper portion of the copying machine 1, and the ADF 3 opens and closes the contact glass 2, that is, lifts up / down.
It is connected to the copying machine 1 via a hinge or the like (not shown) so that it can be lifted down.

The ADF 3 includes a document tray 4 as a document table on which a document bundle P composed of a plurality of documents can be placed;
After separating the originals one by one from the original bundle placed on the original tray 4, the separated originals are conveyed toward the contact glass 2, and the separated originals are fed to the contact glass 2 by the separated paper supply 5. The original conveyed toward and toward the reading position on the contact glass 2 is conveyed and stopped, and reading means (a well-known exposure lamp, mirror, lens, CCD, etc.) of the copying machine 1 disposed below the contact glass 2 is used.
Etc.), the original that has been read by the contact glass 2
Belt unit 6 for unloading the original from the reading position of the contact glass 2 by the conveyor belt unit 6 and disposed below the first discharge tray 8 or the original tray 4 protruding from the side of the copying machine 1. And a reversing sheet discharging means 7 for discharging the sheet to either one of the second sheet discharging trays 9 or returning the sheet to the contact glass 2. The first paper discharge tray 8 may be provided so as to protrude from the side of the ADF 3.

The separating and feeding means 5 comprises a calling roller 10, a feeding roller 11, a reverse roller 12, a pull-out driving roller 13, a pull-out driven roller 14, a registration sensor 15a, and original detection sensors 15b and 15c. These call rollers
10, paper feed roller 11, reverse roller 12, pull-out drive roller
Reference numeral 13 is driven by a paper feed motor (not shown), and is connected to the paper feed motor via a drive system such as a gear mechanism.

The feed motor is driven by an output signal from a controller (not shown). When a feed start signal is input from a main controller (not shown) of the copying machine 1, the controller corrects the feed motor.・
It is designed to be driven in reverse rotation. When the paper feed motor is driven to rotate forward, the call roller 10 rotates clockwise to rotate the original bundle P
, And the sheet feed roller 11 and the reverse roller 12 are rotated clockwise to separate only the uppermost document from the document bundle P. The separated document is sandwiched between a pull-out driving roller 13 rotating in a counterclockwise direction and a pull-out driven roller 14 rotating therewith, pulled out from the sheet feeding roller 11 and the reverse roller 12, and conveyed toward the contact glass 2. You.

When the leading edge of the document is detected by the registration sensor 15a, the controller operates the registration sensor 15a.
The paper feed motor is driven to rotate in the reverse direction based on the output signal from. At this time, the paper feed motor and call roller 10, paper feed roller 1
1.The drive roller interposed between the reverse roller 12 and the pull-out drive roller 13 stops the recall roller 10 and the paper feed roller 11, and the pull-out drive roller 13 is continuously rotated in the counterclockwise direction. By continuing to rotate the clockwise clockwise, the following document is prevented from entering the nip portion between the feed roller 11 and the reverse roller 12 and is not separated.

The registration sensor 15a detects the front and rear ends of the document and outputs a signal to the controller, and the controller grasps the length of the document based on the detection information. Also, the original detection sensor 15
b and 15c are provided apart from each other in the width direction of the original. As shown in FIG. 2, when the width of the original is 230 mm or less from one end of the original, the original detection sensors 15a and 15b are provided.
If neither document is detected and the length in the width direction of the document is between 230 mm and 260 mm from one end of the document, the document detection sensor 15a detects the document and the width of this document is measured from one end of the document. If the direction length is 260 mm or more, the
Both a and 15b detect the original.

The memory of the controller stores the size information of the document corresponding to the length of the document in the conveying direction and the width of the document shown in FIG. 2 in each table map, and the controller stores the sensors 15a to 15c. The size of the document is determined based on the detection information, and the size information is read from each table map in the memory. In this embodiment, each of the sensors 15a to 15c constitutes a document detecting unit.

The call roller 10 is connected to the drive shaft of the sheet feed roller 11 via a belt (not shown). The drive force from the sheet feed roller 11 is applied to the call roller 10 by driving the sheet feed motor. Is transmitted via the Internet. The recall roller 10 is configured to abut on and retract from the document bundle P about the rotation axis of the sheet supply roller 11 by a drive solenoid (not shown).

A transport path 16 composed of a pair of curved guide plates is provided between the paper feed roller 11 and the reverse roller 12 and the contact glass 2, and is separated by the paper feed roller 11 and the reverse roller 12. Originals are transported on path 16
As a result, the upper and lower surfaces are inverted and conveyed toward the contact and the glass 2. The transport belt means 6 includes a transport belt 17, a transport belt driving roller 18 and a transport belt driven roller 19 provided at both ends of the transport belt 17, and a transport belt 17. It comprises a plurality of pressure rollers 20a to 20e for pressing the contact glass 2.

The transport belt driving roller 18 is driven by a transport belt motor (not shown). When the registration sensor 15a detects the leading edge of the original, the motor rotates forward based on a signal from the controller. Thus, the document is conveyed onto the contact glass 2 by driving the conveyance belt 17 via the driving roller 18.

The controller is a registration sensor 15a.
Detects the trailing edge of the document, counts the number of rotation pulses of the conveyor belt motor from the time of detection, and stops the drive of the drive roller 18 and stops the conveyor belt 17 when the rotation pulse reaches a predetermined value. Then, the document is stopped at the reading position on the contact glass 2. Further, when the trailing edge of the document is detected by the registration sensor 15a, the controller drives the sheet feeding motor again, separates the subsequent document as described above, and conveys the document toward the contact glass 2,
When this document is detected by the registration sensor 15a, the paper feed motor is stopped to wait for the next document in advance.

When the original stops at the reading position of the contact glass 2, the copying machine 1 reads and exposes the original. When the reading and the exposure are completed, a signal is input to the controller from the copier 1. When the signal is input, the controller drives the transport belt motor to rotate in the normal direction and the transport belt 17 moves the original from the contact glass 2. It is carried out to the reverse sheet discharging means 7.

The reversing and discharging means 7 includes a reversing driving roller 22, a discharging driven roller 23, a reversing guide roller 24, a reversing driven roller 25, a first
Switching claw 26, second switching claw 27, paper ejection drive roller 28, paper ejection driven roller 29, paper ejection sensor 30, and reversing sensor (document detecting means)
The reversing drive roller 22, the reversing guide roller 24, and the discharge drive roller 28 are driven by a discharge motor (not shown).

The first switching claw 26 is driven to be switched by a first solenoid (not shown). When a single-sided original is discharged, the first switching claw 26 communicates with the contact glass 2 and the first discharge tray 8 to straighten the single-sided original. It is in a state where it stands by at a home position where a paper discharge path for discharging paper is formed. When the controller is in the one-sided mode for conveying a normal one-sided original (the initial setting is set to the one-sided mode even if the one-sided mode is not designated by an operation unit (not shown) provided in the copying machine 1). Without driving the first switching claw 26 at the home position,
After the reading of the document and the exposure are completed, the paper discharge motor is driven at the same time as the transport belt motor is driven. Therefore, the document sandwiched between the reversing drive roller 22 and the discharge driven roller 23 is discharged straight to the first discharge tray 8 without turning the front and back surfaces.

On the other hand, when the double-sided mode is designated by the operation unit provided in the copying machine 1, the controller drives the first solenoid to connect the first switching claw 26 from the home position to the contact glass 2 and the reversing path 32. And after the reading of one side of the double-sided document and the exposure are completed, the transport belt motor is driven and the paper discharge motor is driven at the same time. For this reason, the original is
The sheet is nipped and guided by the sheet discharge driven roller 23 to the reversing path 32, and is conveyed toward the second switching claw 27 by the reversing guide roller 24.

The second switching claw 27 is driven by a second solenoid (not shown), and is not driven by the second solenoid when the document whose one side has been read is carried out of the contact glass 2. Then, the home position is switched to the home position where the reverse return path 33 provided between the reverse path 32 and the contact glass 2 is communicated. The reverse return path 33 and the reverse path 32 constitute a reverse path.

For this reason, the original conveyed out of the contact glass 2 is conveyed to the reversing path 32 by the first switching claw 26, and is then reversed by the second switching claw 27 to the reversing return path 33. Reverse drive roller 22 and reverse driven roller
It is sandwiched by 25 and returned to the contact glass 2. When the leading edge of the document is detected by the reversing sensor 31 provided on the reversing path 32, the controller drives the transport belt motor in the reverse direction to drive the transport belt 17 in the reverse direction, and the reverse sensor 31 detects the trailing edge of the document. When the rotation pulse of the conveyance belt motor from the time point reaches a predetermined value, it is determined that the document has been conveyed to the reading position on the contact glass 2, and the conveyance belt motor is stopped.

When the reading of the original and the exposure are completed at the reading position, a signal is input to the controller from the copying machine 1. When the signal is input, the controller drives the transport belt motor to rotate forward, and furthermore, The solenoid is driven and the driving of the second solenoid is stopped. The first switching claw 26 allows the contact glass 2 to communicate with the reversing path 32, and the second switching claw 27 causes the reversing return path 33.
The document delivered from the contact glass 2 is conveyed by being sandwiched between the reversing drive roller 22 and the reversing driven roller 23, and thereafter, is discharged from the contact glass 2 and the second discharging tray 9. The sheet is pinched by the second sheet discharge tray 29 and discharged onto the second discharge tray 9.

On the other hand, as shown in FIG. 3, the paper discharge driven roller (follower roller) 23 is composed of seven paper discharge driven rollers 23a to 23g which are arranged apart from each other in the width direction of the document. The reversing drive roller (drive roller) 22 is driven by the driven rollers 23a to 23a.
It is composed of seven discharge driven rollers (not shown) that are slid on 23 g. Further, the ADS 3 of the present embodiment is configured such that one end surface in the width direction of the document returned to the contact glass 2 is
3 is a so-called end-face reference in which a document is conveyed or returned to the contact glass 2 with reference to the back side of the sheet. The discharge driven roller 23a and the reversing drive roller 22 slidably contacting the roller 23a are shown in FIG. As shown in (1), reference driving rollers and reference driven rollers are provided so as to be in sliding contact with one end surface in the width direction of documents of all sizes, and are always in sliding contact with each other. The paper discharge driven roller 23a is pressed against the reversing drive roller 22 by an elastic member such as a rubber material or a spring material.

Further, the paper discharge driven rollers 23b to 23g and these rollers
The reversing drive rollers 22 slidably contacting 23b to 23g are arranged at positions corresponding to the originals of various sizes and are slidably in contact with the other end surfaces in the width direction of the originals of various sizes.
23g is provided so as to be able to slide and separate from the reverse driven roller 22. More specifically, as shown in FIG.
23g is X (X is the same amount) from the end face of various size documents
It is provided at a position away from the camera.

As shown in FIG. 4, the driven discharge rollers 23b to 23g are rotatably mounted on the other end of an arm 42 whose one end is swingably mounted on a frame 41 constituting a paper discharge path. The arm 42 slides and separates from the reversing drive roller 22 through an opening 41a formed in the frame 41. The arm 42 is provided for each of the driven driven rollers 23b to 23g.

As shown in FIG. 5, cam surfaces 43a to 48a of a plurality of cams 43 to 48 are slidably contacted and separated from the arm 42. The cams 43 to 48 are shown in FIG. So that the phases of the cam surfaces 43a to 48a are shifted by 60 °.
Installed on 49. Also, the cam surfaces 43a to 48a are shown in FIG.
(As each cam 43-48 has the same shape,
43 only), body of cam 43 by spring 55
It is urged outward from 43b.

A driven pulley 50 is provided at an end of the drive shaft 49. The driven pulley 50 is connected to a drive pulley 52a attached to an output shaft of a drive motor 52 via a belt 51. I have. Therefore, when the drive motor 52 is driven, the driven pulley 50 is driven via the belt 51, and the cam surfaces 43a to 48a of the cams 43 to 48 are driven via the drive shaft 49.
Contact the arm 42 at a phase interval of 60 °, and
23b to 23g are sequentially brought into contact with the reversing drive roller 22.

A home position lever 53 is provided on the drive shaft 49 on the driven pulley 50 side. The home position lever 53 is detected by a home position sensor 54. This home position sensor 54 has cam surfaces 43a to 48a of all the cams 43 to 48 as arms.
When the lever 53 is detected at this position, the cams 43 to 48 are detected to be at their home positions, and a signal is sent to the controller. Output.

The controller reads the information stored in the table map of the memory based on the detection information of each of the sensors 15a to 15c, and drives the drive motor 52 to move the size of the document from the cams 43 to 48 located at the home position. , One of the cams 43 to 48 at a position corresponding to the arm 42 is brought into contact with the arm 42. At this time, one of the paper discharge driving rollers 23b to 23g is rotated by the arm 42. The other end of the document returned to the contact glass 2 is held in sliding contact with any one of the reference numerals 22.

For this reason, both ends of the original document are
Both ends are sandwiched by any one set of the sheet discharge drive roller 23a, the reverse drive roller 22, and the sheet discharge drive rollers 23b to 23g, and are returned to the contact glass 2. In the present embodiment, the cams 43 to 48, the drive shaft 49, the driven pulley 50, the belt
The drive roller 52, the home position lever 53, the home position sensor 54, and the controller constitute a driven roller control means 56.

Next, a method for conveying a one-sided original and a two-sided original will be described. First, a method for conveying a one-sided original will be described. First, after the document bundle P is set on the document tray 4 and the start switch is pressed, the copier 1
A paper feed start signal is input to F3. At this time, the controller drives the drive solenoid to bring the call roller 10 into contact with the document bundle P, and drives the paper feed motor forward to rotate the call roller clockwise to position the document roller P on the upper layer. The document is fed, and the feed roller 11 and the reverse roller 12 are rotated clockwise to separate only the top document from the document bundle P.

The separated document is sandwiched between a pull-out driving roller 13 rotating in a counterclockwise direction and a pull-out driven roller 14 rotating therewith, pulled out from the sheet feeding roller 11 and the reverse roller 12 and directed toward the contact glass 2. Transported. Next, when the registration sensor 15a detects the leading edge of the original, the feed roller 10 and the feed roller 10 are fed by a driving system interposed between the feed roller 10, the feed roller 11, the reverse roller 12, and the pull-out drive roller 13. The roller 11 is stopped, the pull-out drive roller 13 is continuously rotated in the counterclockwise direction, and the reverse roller 12 is continuously rotated in the clockwise direction. The nip portion is prevented from entering the nip portion and is not separated.

When the registration sensor 15a detects the leading edge of the document, the transport belt driving roller 18 is driven by the transport belt motor, so that the transport belt 17 is driven and the document is transported onto the contact glass 2. When the registration sensor 15a detects the trailing edge of the document during this conveyance, the controller counts the rotation pulses of the conveyance belt motor from this detection time, and when the rotation pulse reaches a predetermined value, drives the driving roller 18. The document is stopped at the reading position on the contact glass 2 by stopping and stopping the transport belt 16.

On the other hand, the controller operates the registration sensor 15a.
When the trailing edge of the original is detected, the paper feed motor is driven again, the subsequent original is separated and transported toward the contact glass 2 as described above, and the original is detected by the registration sensor 15a. At this point, the paper feed motor is stopped, and the next original is put on standby. When the document is stopped at the reading position of the contact glass 2, the copying machine 1 reads and exposes the document. When the reading and the exposure are completed, the transport belt motor is driven to rotate forward, and the transport belt 17 transports the original from the contact glass 2 to the reverse discharge means 7.

At this time, since the first switching claw 26 is waiting at the home position, the controller drives the conveyance belt motor after the completion of the reading of the original and the exposure, and at the same time, drives the discharge motor. For this reason, the reversing drive roller
The document sandwiched between the paper discharge roller 22 and the paper discharge driven roller 23 is discharged straight to the first paper discharge tray 8 without turning over the front and back surfaces.

When a feed start signal for the next original is input, the drive solenoid is driven to bring the call roller into contact with the original bundle P, and the paper feed motor is driven again to call the call roller 10 and the paper feed roller. By driving 11 and the like, the following document is separated as described above and conveyed toward the contact glass 2, and the above-described processing is continued. The operation of the paper discharge driven roller 23 will be described in detail when the following two-sided document conveyance process is described. The operation of the paper discharge driven roller 23 during single-sided conveyance is the same as the operation of the two-sided document.

Next, a method of transporting a double-sided document will be described with reference to the flowchart of FIG. Note that the flow of FIG. 8 is executed by the controller. Note that the method of transporting the original conveyed out of the contact glass 2 will be described because the method of discharging and returning the original conveyed from the contact glass 2 is different from the method of single-sided conveyance when conveying a double-sided original.

First, it is determined whether reading of the front side of the double-sided document on the contact glass 2 has been completed (step S1).
When the processing is completed, the size information of the document stored in the table map of the memory is read based on the detection information of each of the sensors 15a to 15c. At this time, for example, if the document size is B
If it is 6Y (horizontal), the drive motor 52 from the home position to the time when the paper discharge driven roller 23d slides on the reversing drive roller 22
Drive pulse amount of the motor
52 is driven (steps S3 and S4).

For this reason, the cam 45 abuts on the arm 42, and only the paper discharge driven roller 23d is moved through the arm 42 to the reversing drive roller 22d.
In sliding contact with At this time, since the other cams 43, 44, 46, 47, and 48 have the phase of the cams 45 and 60 °, the other discharge driving rollers 23
b, 23c, 23e, 23f, and 23g do not slidably contact the reversing drive roller 22;
Can be brought into sliding contact with.

Next, when a re-feed start signal is input from the copying machine 1, the first switching claw 26 is operated by the first solenoid.
Moves from home position to contact glass 2 and reversal path
The paper discharge motor is driven at the same time as the conveyor belt motor is driven. For this reason,
Both sides of the double-sided document are nipped by the reversing drive roller 22 and the discharge driven roller 23a and the reversal drive roller 22 and the discharge driven roller 23d, guided to the reversing path 32, and conveyed toward the second switching claw 27. .

Since the cam surface 45a is urged to the arm 42 by the spring 55 during this conveyance, the arm 42 may swing via the driven discharge roller 23d when the document thickness is different. However, the amount of movement of the arm 42 can be absorbed by the spring 55, and the paper discharge driven roller 23d can be reliably brought into sliding contact with the reversing drive roller 22. When the leading edge of the document is detected by the reversing sensor 31 at this time, the reversing belt motor is driven to rotate in the reverse direction, the transport belt 17 is driven to rotate in the reverse direction, and the second switching claw 27 is brought into contact with the contact glass 2 by the second solenoid. Since the position is switched to a position communicating with the reverse return path 33, the original conveyed from the contact glass 2 is moved by the second switching claw 27 to the reverse return path 33.
In the state where the front and back surfaces are inverted, the sheet is sandwiched between the inversion driving roller 22 and the inversion driven roller 25 and returned to the contact glass 2.

Next, the original is returned on the contact glass 2 by the transport belt 17 driven in reverse, and the rotation pulse of the transport belt motor from the time when the leading edge of the original is detected by the reversing sensor 31 has reached a predetermined value. At this time, it is determined that the document has been transported to the reading position on the contact glass 2, and the transport belt motor is stopped. Next, it is determined whether or not the trailing edge of the document is detected by the reversing sensor 31 (step S5). When the trailing edge of the document is detected by the reversing sensor 31, it is determined that the reversing operation has been completed and the drive is performed. Drives the motor 52 and moves the home position lever 53
Is stopped by the home position sensor 54, the drive motor 52 is stopped. For this reason, the paper discharge driven roller 23d is separated from the reversing drive roller 22 and the other paper discharge drive roller
23b, 23c, 23e, 23f and 23g are also located at the home position.

Next, when reading and exposure of the original on the contact glass 2 are completed, a refeed start signal is input from the main controller, so that the transport belt motor is driven to rotate forward and the first solenoid is driven. At the same time, the driving of the second solenoid is stopped, the first switching claw 26 connects the contact glass 2 to the reversing path 32, and the second switching claw 27 connects the reversing return path 33 to the second discharge tray 9. As a result, the document discharged from the contact glass 2 is conveyed while being sandwiched between the reversing driving roller 22 and the reversing driven roller 23, and is nipped by the discharging driving roller 28 and the discharging driven roller 29, and the second discharge tray 9. The paper is ejected on top.

At this time, both sides of the double-sided document are sandwiched by the reversing drive roller 22 and the discharge driven roller 23a, the reversing drive roller 22 and the discharge driven roller 23d under the above-described control, and are discharged onto the second discharge tray 9. Because the paper is printed, the document is discharged straight onto the second discharge tray 9. Also, when a single-sided original is conveyed, the opposite ends of the original are rotated by the reversing drive roller 22, the discharge driven roller 23a, the reversal drive roller 22, and the discharge driven
Since both ends are sandwiched by any one of 23b to 23g and discharged onto the first discharge tray 8, the document can be discharged straight onto the first discharge tray 8.

As described above, in this embodiment, the reference reversing drive roller 22 and the paper discharge driven roller 23a are disposed so as to be in sliding contact with one end surface in the width direction of the original of all sizes.
A plurality of reversing drive rollers 22 and discharge driven rollers 22b to 22g are provided so as to slide on the other end surfaces in the width direction of various size documents, and when returning a document to the contact glass 2 based on the document end surface, By bringing any one of the paper discharge driven rollers 23b to 23d located at a position corresponding to the size of the document returned to the contact glass 2 into sliding contact with the reversing drive roller 22,
Reversing drive roller 22, discharge driven roller 23a, and discharge driven roller
The document can be returned to the contact glass 2 while holding both end faces of the document by any one of 23b to 23d and the reversing drive roller 22.

Therefore, regardless of the size of the original, the conveying force applied in the width direction of the original can be made constant, and the skew of the original can be prevented, thereby improving the original conveying performance. .

[0054]

According to the first aspect of the invention, the conveying force applied in the width direction of the original can be made constant regardless of the size of the original, and the skew of the original can be prevented. Transfer performance can be improved.

[Brief description of the drawings]

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

FIG. 2 is a diagram illustrating a relationship between a length of a document in a conveying direction, a length in a width direction of the document, and a document size according to the embodiment;

FIG. 3 is a diagram illustrating a positional relationship between a document size and a discharge driven roller in an embodiment.

FIG. 4 is a schematic side view of a driven roller control unit of one embodiment.

FIG. 5 is a perspective view of a driven roller control unit of one embodiment.

FIG. 6 is a side view of the cam showing a positional relationship of the cam according to the embodiment.

FIG. 7 is a sectional view of a cam according to an embodiment.

FIG. 8 is a diagram illustrating a method of controlling a driven paper ejection roller according to an embodiment.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 copy machine (image reading device) 2 contact glass 3 ADF (automatic document feeder) 4 document tray (document placement table) 5 separation paper feeding device 6 transport belt device 7 reverse discharge device 15 a registration sensor (document detection device) 15 b , 15c Document detection sensor (document detection means) 22 Reversing drive roller (drive roller) 23a to 23g Discharge driven roller (driven roller) 56 driven roller control means

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 2H076 BA22 BA24 BA42 BA48 BB04 3F049 DA11 DA12 EA17 EA24 LA03 LB02 3F053 EA03 EB01 EC02 EC06 ED03 LA03 LB02 3F100 AA03 BA13 CA12 CA15 DA04 EA08 EA13 EA11 A11 BA102 A

Claims (1)

[Claims] A separating and feeding means for separating originals one by one from a bundle of originals placed on an original placing table and feeding the separated originals toward a contact glass; Transport belt means for transporting the document fed by the paper means to a reading position on the contact glass, and carrying out the document which has been read at the reading position from the contact glass; and A reversing sheet discharging means for discharging the conveyed document onto a paper discharge tray or reversing it on a reversing path and returning it to a contact glass; and detecting a size of the document conveyed from the document table. Document detecting means for conveying the document to the contact glass with reference to one end surface in the width direction of the document returned to the contact glass. An automatic document feeder adapted to return the original to a contact glass, wherein the reverse discharge means is disposed at a distance in the width direction of the original and returns the original toward a contact glass; In the automatic document feeder provided for each driving roller and having a plurality of driven rollers slidingly contacting the driving roller, the driving roller and the driven roller may be in contact with one end surface in the width direction of all sizes of originals. And a plurality of driving rollers disposed so as to abut on the other end in the width direction of the originals of various sizes at a position corresponding to the originals of various sizes. A roller and a plurality of driven rollers provided so as to be able to slide and separate from the driving roller; one of the plurality of driven rollers corresponding to the driven roller based on detection information of the document detecting means. Drive An automatic document feeder which characterized in that a driven roller control means for sliding contact with the roller.