JP5669378B2 - Document feeder - Google Patents

Description

  The present invention provides a document transport that supplies a document from a paper feed tray onto a platen glass of an image forming apparatus such as a copying machine or an image scanner, and reads the document image on the platen glass and then discharges the document to a discharge tray. It relates to the device.

  In an image forming apparatus such as a copying machine or a scanner, a document conveying device called an ADF (Auto Document Feeder) is used to automatically supply a document onto a platen glass of an image reading unit, and images are printed on both sides. The double-sided original document can be read.

  Conventionally, as this type of document conveying device, for example, the one disclosed in Patent Document 1 is known. This document transport device has two modes. In the first mode, a single-sided document is read and directly discharged onto the paper discharge tray. In the second mode, the first side of a double-sided document is read. The paper is temporarily fed to the paper discharge tray. However, the paper is not completely discharged to the paper discharge tray, but is switched back, and is fed again to the document feed path through the duplex feeding path. Then, after reading the second side and feeding it to the paper discharge tray, it is switched back to the paper discharge tray again so that the page order is aligned, and then switched to the original document feed path via the double-sided feed path. The paper is fed again and then discharged and stacked on the paper discharge tray. Therefore, the double-sided original is circulated by a roller for discharging and reversing the entrance of the paper discharge tray and a double-sided feeding path for feeding the original from the paper discharge tray to the original feeding path. The discharge of the double-sided document is reversed by the roller, and is discharged to the discharge tray by the roller through the same path as that of the read document on the second side.

JP 7-175279 A

  However, in the above-described conventional document conveying device, in the case of a double-sided document, if an attempt is made to sequentially stack the page order on the paper discharge tray, the document needs to pass through the image reading unit three times. Of these, when the document is passed for the third time, it passes through the image reading unit even if the document is not read, and during that time, the subsequent document cannot be fed. For this reason, there is a problem that it takes time to read continuous double-sided originals.

  Further, since the number of times of passing through the image reading unit is large, the image reading unit is likely to get dirty, and there is a possibility that the reading accuracy of the original document is lowered and the occurrence rate of reading failure is increased.

  Accordingly, in order to solve the above-described problems, the present invention is provided with a conveying unit that shortens the waiting time of continuously fed documents, thereby efficiently performing a process for reading a plurality of double-sided documents, and An object of the present invention is to provide a document conveying device that can be performed speedily.

In order to solve the above-described problems, a document transport device according to the present invention includes a paper feed tray on which a document is placed, a transport unit that transports a document fed from the paper feed tray, and an image that reads both sides of the transported document. A reading unit; a discharge tray that discharges a document that has been read on both sides; and a first switchback path that switches back the document whose surface has been read by the image reading unit and transports the document back to the image reading unit. a first switchback section, and a second switchback portion having a second switchback path for discharging the original double-sided by the image reading unit is read to the discharge tray switched back, The first switchback unit sequentially switches back the documents whose surfaces have been read by the image reading unit and transports them to the image reading unit, and also includes the first switchback unit. A document that has been switched back and a document that has been switched back in the second path, and is conveyed in the opposite direction while rubbing against each other, and the document that has been switched back in the second switchback path and the image reading unit. The document whose surface is read by the sheet is conveyed in the same direction in a state of being overlapped, and the second switchback unit sequentially switches back the document whose other surfaces are read by the image reading unit. In addition to conveying toward the tray, the document after switching back and the document before switching back are rubbed against each other in the second switchback path and conveyed in the opposite directions .

  According to the document conveying device of the present invention, the first and second switchback portions having a pair of switchback rollers for conveying two documents in a reverse direction in a state of being stacked are provided. Therefore, it is possible to perform conveyance and double-sided reading of the front and back sides in a state in which the interval between the preceding first document and the subsequent second document is reduced. For this reason, the speed of the continuous reading is increased, and the entire original conveying apparatus is reduced in size.

1 is a cross-sectional view illustrating an overall configuration of a document conveying device according to the present invention. FIG. 3 is a cross-sectional view of a main part of a transport reading unit that constitutes the document transport apparatus. It is explanatory drawing which shows the structure of the drive system of the said conveyance reading unit. 6 is a timing chart of processing starting from feeding of the first and second originals in the drive system. 4 is a timing chart of processing up to discharge of first and second originals in the drive system. FIG. 5 is an explanatory diagram illustrating a document transport operation (stage 1). FIG. 6 is an explanatory diagram illustrating a document transport operation (stage 2). FIG. 6 is an explanatory diagram illustrating a document transport operation (stage 3). FIG. 6 is an explanatory diagram showing a document transport operation (stage 4). FIG. 10 is an explanatory diagram illustrating a document transport operation (stage 5). FIG. 6 is an explanatory diagram illustrating a document transport operation (stage 6). FIG. 6 is an explanatory diagram illustrating a document transport operation (stage 7). FIG. 10 is an explanatory diagram illustrating a document transport operation (stage 8). FIG. 10 is an explanatory diagram illustrating a document transport operation (stage 9). FIG. 6 is an explanatory diagram illustrating a document transport operation (stage 10).

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of a document conveying device according to the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, the document conveying apparatus 1 according to the present invention includes a main body unit 2 having an image reading unit 4, and a conveying / reading unit 3 attached to the upper side of the main body unit 2 so as to be opened and closed. .

  The image reading unit 4 reads a document passing through the upper surface of the first contact glass 6 with the optical unit 5 fixed. Further, a second contact glass 7 having a plane space for placing a document is provided on the upper surface of the main unit 2, and the image reading unit 4 is arranged for the document set on the contact glass 7. It can be read by moving the optical unit 5.

  The image reading unit 4 includes a light source 10 such as a lamp, a plurality of mirrors 11, a lens 16, a photoelectric conversion element 17 such as a CCD, and the like. The document that is conveyed or placed is irradiated with light emitted from the light source 10 via the first contact glass 6 or the second contact glass 7. Then, the light irradiated and reflected on the document surface is reflected several times by the plurality of mirrors 11 and then photoelectrically converted by the photoelectric conversion element 17 through the lens 16 to read the image of the document.

  Next, the configuration of the transport reading unit 3 will be described. As shown in FIGS. 1 and 2, the transport reading unit 3 includes a paper feed tray 20 on which a plurality of documents can be placed, and a support tray 21 that raises and lowers the placed documents to a feeding position. And a paper discharge tray 22 for storing the document that has been read.

  The transport reading unit 3 includes a paper feed path 23 that feeds one by one from a plurality of documents stacked on the paper feed tray 20, and a first contact glass 6 from the paper feed path 23. The apparatus includes a reading conveyance path 24 that extends through the sheet, and a document conveyance means that includes a discharge path 25 that extends from the conveyance path 24 to a discharge port of the discharge tray 22.

  On the downstream side of the support tray 21, a feed roller 27 for feeding out the original abutted by the raising of the support tray 21, a paper feed roller 28 for feeding the fed original, and the paper feed roller 28. A separation pad 29 that presses against and separates the originals one by one, and a registration roller pair 30 that feeds toward the first contact glass 6 after abutting and aligning the leading edges of the originals that are separated and fed one by one. With.

  The reading conveyance path 24 is provided with a first lead roller pair 32 disposed on the upstream side of the first contact glass 6 and a second lead roller pair 33 disposed on the downstream side.

  The first stage of the paper discharge tray 22 includes a first switchback portion 41 for temporarily retracting a document on which an image on one surface (front surface) has been read and then transporting it again. A second switchback unit 42 is provided for temporarily storing the document from which the image has been read and then storing it in the paper discharge tray 22. The first switchback unit 41 includes a first switchback path 45 that also serves as the paper discharge path 25, and a re-transport path 47 that merges from the upstream side of the first switchback path 45 toward the registration roller pair 30. And a first switchback roller pair 43 provided at an end portion of the first switchback path 45 and a standby roller pair 48 provided on the re-conveying path 47. The first switchback roller pair 43 and the standby roller pair 48 are constituted by drive rollers 43a and 48a, one of which can be rotated forward and reversely, and the other of which are driven free rotation rollers 43b and 48b. Arranged as possible. Hereinafter, forward rotation refers to counterclockwise rotation that feeds the document downstream, and reversal refers to clockwise rotation that feeds the document upstream.

  The second switchback portion 42 is folded from the second switchback path 46 extending from the second read roller pair 33 toward the lower side of the paper discharge tray 22 and the upstream side of the second switchback path 46. A reverse discharge path 49 that merges with the switchback path 45 is provided, and a second switchback roller pair 44 is provided in the vicinity of a portion where the second switchback path 46 and the reverse discharge path 49 are branched. One of the second switchback roller pair 44 is a drive roller 44a capable of normal rotation and reverse rotation, and the other is a rotation-free driven roller 44b, which are disposed so as to be capable of being pressed against and separated from each other.

  Further, on the downstream side of the second read roller pair 33, the flow of the document is alternately switched toward either the first switchback path 45 or the second switchback path 46 in accordance with the document reading process. Switching means is provided. This switching means has a three-way path surface, and the three-way path surface is constituted by a switching flapper 34 that can be rotated by a rotation shaft 36. The switching flapper 34 can be rotated within the range of the thickness width of the original on each path surface. The first path surface 34 a is provided for guiding the document to the first switchback portion 41, the second path surface 34 b is provided for the second switchback portion 42, and the third path surface 34 c is provided for guiding the document toward the paper discharge tray 22. ing.

  Also, as shown in FIG. 2, various sensors are provided at various places where the document passes. An empty sensor 51 for detecting a document fed from the support tray 21 is provided in the vicinity of the feeding roller 27, and a separation sensor 52 for detecting a document separated into one sheet is provided at the tip of the paper feed roller 28. In addition, a registration sensor 53 and a lead sensor 54 are provided on the upstream conveyance path of the first contact glass 6, and a reverse sensor 55 and a reverse discharge sensor 56 are respectively disposed on the downstream conveyance path. The function of each sensor will be described in detail in a drive system timing chart and an operation explanatory diagram to be described later.

  FIG. 3 shows the drive system of each roller pair. There are mainly three motors (M1, M2, M3) for rotational driving and two solenoids (SOL1, SOL2) for controlling the separation of the roller pairs. The motor M1 is supplied to the paper feed roller 28, the drive roller 30a of the registration roller pair 30 and the drive roller 32a of the first lead roller pair 32, of which the drive roller 30a of the paper feed roller 28 and the registration roller pair 30. Are connected via electromagnetic clutches CL1 and CL2. The motor M1 is rotationally driven to convey the document toward the first platen glass 6, and the driving roller 30a of the paper feed roller 28 and the registration roller pair 30 is driven at a predetermined timing by electromagnetic clutches CL1 and CL2. Stop control is possible. The motor M2 is supplied to the drive roller 43a of the first switchback roller pair 43 and the drive roller 44a of the second switchback roller pair 44, and can perform forward rotation, reverse rotation, and stop control. Further, the motor M3 is supplied to the driving roller 48a of the standby roller pair 48 so that normal rotation and stop control are possible.

  SOL1 is connected to the driven roller 43b of the first switchback roller pair 43 and the drive roller 44a of the second switchback roller pair 44, respectively, and is controlled so as to be able to press and separate from the corresponding drive roller 43a and driven roller 44b. The The SOL 2 is provided in the vicinity of the rotation shaft 36 of the switching flapper 34 and is controlled to rotate clockwise and counterclockwise with a predetermined rotation width.

  Next, based on FIGS. 6 to 15 and with reference to the timing charts of FIGS. 4 and 5, the operation of the document feeder of the present invention will be described along the flow of the document. When the empty sensor 51 first detects that an original is placed on the paper feed tray 20, the paper feed motor M1 is driven. When the electromagnetic clutch CL1 is turned on, the feeding roller 27 and the paper feed roller 28 are rotationally driven. As a result, the uppermost document placed on the sheet feed tray 20 is sequentially fed out and separated into one document P1 by the separation pad 29. Note that the initial switchback roller pair 43 and the second switchback roller pair 44 are set in a separated position by the initial operation at the start of document feeding, and the switching flapper 34 is guided to the first switchback path 45. (Fig. 6 (00)).

  When the registration sensor 53 detects the leading edge of the document P1 that has passed through the separation pad 29, the document P1 is transported by a predetermined amount from the point of detection, thereby aligning the leading edge of the document P1 with the nip portion of the registration roller pair 30. Then, the skew is removed (FIG. 6 (01)).

  Thereafter, the electromagnetic clutch CL2 is turned on, and the registration roller pair 30 is driven to rotate counterclockwise. The original P1 is conveyed along the U-shaped paper feed path 23 by the first and second read roller pairs 32 and 33 to be driven, and the first platen glass 6 is placed on the first platen glass 6 in a state where the front surface and the back surface are reversed. Pass through. When passing over the first platen glass 6, the surface of the document P1 is read (FIG. 6 (02)).

  The document P1 that has passed through the first platen glass 6 is guided to the first switchback path 45 via the switching flapper 34. If the trailing edge of the first document P1 is detected by the post-separation sensor 52 while the leading edge of the first document P1 is guided to the first switchback path 45, the second document P2 is fed. When started by the paper roller 28 and the registration sensor 53 detects the trailing edge of the document P1, the electromagnetic clutch CL2 is turned off and the registration roller pair 30 is stopped (FIG. 7 (03)).

  The leading edge of the fed second document P2 comes into contact with the nip portion of the registration roller pair 30 and is aligned, and the conveyance of the document P2 is temporarily stopped. (FIG. 7 (04)).

  Then, after a predetermined time has elapsed since the electromagnetic clutch CL1 was turned off, the electromagnetic clutch CL2 is turned on. As a result, the registration roller pair 30 is driven, and the document P2 is sent out toward the first platen glass 6. The above-mentioned predetermined time is a predetermined time for keeping the interval between the original P1 and the original P2 fed in advance. On the other hand, when the leading edge of the document P1 is detected by the reverse sensor 55, the reverse discharge motor M2 is driven to rotate forward, and the first solenoid SOL1 is turned on (sucked). As a result, the driving roller and the driven roller of the first switchback roller pair 43 are rotated and driven, and the document P1 is further advanced toward the sheet discharge tray 22 (FIG. 7 (05)).

  While the original P2 is conveyed toward the first platen glass 6, the original P1 that has passed through the first platen glass 6 has passed a certain period of time after its rear end is detected by the reverse sensor 55. Then, the reverse discharge motor M2 is stopped in a state where it is nipped by the first switchback roller pair, and then the reverse switch motor M2 is driven in reverse to drive the first switchback roller pair 43 in the reverse rotation, and the document. P1 is switched back. (FIG. 8 (06), (07)).

The document P1 switched back by the first switchback roller pair 43 is transported along the re-transport path 47. Then, after the front end portion of the original P1 is nipped by the standby roller pair 48 that is rotationally driven, the standby motor M3 is stopped, whereby the original P1 is temporarily stopped. When the original P1 is nipped and stopped by the standby roller pair 48, the first solenoid SOL1 is turned OFF (suction is released), the first switchback roller pair 43 is separated, and the reverse discharge motor M2 is switched to the normal rotation drive. .
In this state, the document P2 that has passed through the first contact glass 6 is transported into the first switchback path 45, is transported under the document P1 stopped in the first switchback path 45, and is discharged into the paper discharge tray 22. Conveyed to the side. At this time, since the first switchback roller pair 43 is separated, the leading edge of the document P2 is conveyed to the discharge tray side in the first switchback path 45 without any problem. In addition, since the driving roller 43a of the separated first switchback roller pair 43 is driven to rotate in the forward direction, the document P2 is supplied with a conveying force when the driving roller 43a comes into contact and is smoothly fed. (FIG. 8 (08), FIG. 9 (09)).

The electromagnetic clutch CL2 through which the original P2 passes the registration sensor 53 is turned off. Further, the standby motor M3 is driven after a predetermined time has elapsed since the trailing edge of the document P2 was detected by the registration sensor 53. As a result, the leading edge of the document P1 stopped on the re-conveyance path 47 is sent out so as to contact the registration roller pair 30. During this time, the original P2 is conveyed on the first switchback path 45 so as to pass the original P1 by the forward rotation of the first read roller pair 32, the second read roller pair 33, and the first switchback roller pair 43. . At this time, the first switchback roller pair 43 is transported in different directions in a part of the first switchback path of the document P1 and the document P2 while being separated. Then, after the trailing edge of the document P2 is detected by the lead sensor 54, the first solenoid SOL1 is turned on after the time for the trailing edge of the document P2 to reach the reading position of the first contact glass 6 has elapsed. One switchback roller pair 43 is nipped. As a result, the first switchback roller pair 43 overlaps and presses the original P1 and the original P2, and in this state, the original P1 and the original P2 are conveyed in different directions in a part of the first switchback path. However, since the friction coefficient of the driving roller 43a is set higher than that of the original and the driven roller 43b, the original P1 sandwiched between the driven roller 43b and the original P1 is the standby roller 48, the registration roller pair 30, the first roller The document P2 that is fed toward the document reading 4 by the read roller pair 43 and sandwiched between the driving roller 43a and the document P1 is sent to the paper discharge tray 22 side against the document P1 by the driving roller 43b. (FIG. 9 (10), (11)).
Then, the first switchback roller pair 43 is driven from the normal rotation drive to the reverse rotation by switching the reverse discharge motor M2 from the normal rotation drive to the reverse rotation drive after a predetermined time after the rear end portion of the document P2 is detected by the reverse sensor 55. Then, the document P2 is switched back. At this time, the rear end portion of the document P1 passes through the nip position of the first switchback roller pair 43 and does not affect the switchback operation of the document P2. The switched-back original P2 is conveyed along the re-conveying path, and when nipped by the standby roller pair 48, the standby motor M3 is stopped and the first separation solenoid SOL1 is turned OFF to stop the original P1 and wait.

On the other hand, the first document P1 is guided to the second switchback path 46 through a path whose front end is switched by the switching flapper 34 after the back side is read. The switching flapper 34 forms a path that rotates clockwise and communicates with the second switchback path 46 when the rear end portion of the second original P2 is detected by the reverse sensor 55. When the rear end portion of the document P1 is detected by the read sensor 24, the second solenoid SOL2 is turned on (sucked), and the second switchback roller 44 is brought into a pressure contact state. (FIG. 10 (12), (13), FIG. 11 (14), (15)).
The document P2 that is nipped by the standby roller pair 48 and waits is driven by the standby motor M3 after the trailing edge of the document P1 is detected by the registration sensor 53 to come into contact with the stopped registration roller pair 30, and the leading edge of the document P2 Be aligned. Then, by turning on the electromagnetic clutch CL <b> 2, the registration roller pair 30 is rotationally driven, and the document is conveyed again toward the document reading unit 4.

When the original P1 is conveyed to the second switchback path 46 and the rear end thereof is detected by the reverse sensor 55, the reverse discharge motor M2 is switched from the reverse drive to the normal drive after a predetermined time. As a result, the second switchback roller pair 44 is switched from the forward rotation drive to the reverse rotation drive, and the document P1 is switched back. The document P1 that has been switched back is sent to the first switchback roller pair 43 along the reverse discharge path 26 and is discharged to the discharge tray 22 by the first switchback roller pair 43.
On the other hand, the original P2 is conveyed to the original reading unit 4 following the original P1, the back side is read, and is conveyed to the second switchback path 46. At this time, when the reversing sensor 55 detects the leading edge of the document P2, the second solenoid SOL2 is turned OFF (adsorption release), and the second switchback roller 44 is separated. Then, the document P1 and the document P2 are conveyed so as to pass each other in the second switchback path. (FIG. 11 (16)) (FIG. 12 (17)).
When the rear end portion of the document P1 is detected by the reverse discharge sensor 55, the second solenoid SOL2 is turned on and the second switchback roller 44 comes into pressure contact again. At the same time, the reverse discharge motor M2 is switched from the forward rotation drive to the reverse rotation drive. Thereafter, the reverse discharge motor M2 is switched from the reverse rotation drive to the normal rotation drive, and the second switchback roller pair 44 is switched from the normal rotation drive to the reverse rotation drive. As a result, the document P2 is switched back and sent to the first switchback roller pair 43 along the reverse discharge path 26. Then, the paper is discharged to the paper discharge tray 22 by the first switchback roller pair 43.

  The third original P3 is fed by a predetermined time after the second original P2 passes the registration sensor 53 and the electromagnetic clutch CL1 is turned on. The third original P3 is conveyed in the same manner as the first original P1, and the fourth original P4 following the third is conveyed in the same manner as the second original P2. It becomes. (FIG. 12 (18), (19), FIG. 13 (20), (21)).

When the second document P2 is discharged to the discharge tray 22, the document P2 and the third document P3 sent to the first switchback path 41 are overlapped and conveyed to the discharge tray 22 side. Is done. At this time, the document P2 reaches the first switchback roller pair 43 first, and then the document P3 is conveyed to the first switchback roller pair 43. That is, here, the original P3 is conveyed in the same direction with respect to the original P2 in a state shifted in a direction different from the direction of the paper discharge tray 22. Then, the reverse discharge motor M2 that is normally driven after a predetermined time from the time when the rear end portion of the document P4 is detected by the reverse sensor 56 is stopped. Thereby, the first switchback roller pair 43 is temporarily stopped. At this time, the original P2 is discharged to the paper discharge tray 22, and the end of the original P3 on the side different from the paper discharge tray 22 is nipped by the first switchback roller pair 43. Then, when the reverse discharge motor M2 is driven in reverse from this state, the first switchback roller pair 43 is driven in reverse to switch back the document P3.
The first switchback roller pair 43 is driven to rotate forward in a separated state until the leading edge of the document P3 reaches the first switchback roller pair 43, and the leading edge of the document P3 reaches the first switchback roller pair 43. At that time, the nipping is performed with the forward rotation driving (FIG. 13 (22), FIG. 14 (23), (24), (25)).

  The document P2 that precedes the first switchback path 45 is accommodated in the paper discharge tray 22 by the first switchback roller pair 43, and the subsequent document P3 stops at the position where the trailing edge is detected by the reverse sensor 55. Then, the sheet is sent to the re-conveying path 47 so as to pass the fourth original P4 whose surface has been read. Thereafter, a plurality of continuous document reading processes are performed by repeating the procedures from FIG. 1 to FIG. 15 (FIG. 15 (26), (27), (28)).

  As described above, the document conveying apparatus 1 according to the present invention has a structure in which the first and second switchback portions are provided to retract and re-transport two documents while passing each other. It has become possible to perform conveyance and double-sided reading of the front and back sides in a state in which the interval between the first original and the subsequent second original is reduced. For this reason, the speed of continuous reading is increased, and the size of the entire document conveying apparatus is reduced. Further, since the roller pair constituting the first and second switchback portions is controlled so as to be able to rotate forward, reverse, stop and separate from the nip, the document can be stably and according to various passing patterns. It can be transported smoothly.

DESCRIPTION OF SYMBOLS 1 Document conveying apparatus 2 Main body unit 3 Conveyance reading unit 4 Image reading part 5 Optical part 6 1st contact glass 7 2nd contact glass 10 Light source 11 Mirror 16 Lens 17 Photoelectric conversion element 20 Paper feed tray 21 Support tray 22 Paper discharge Tray 23 Paper feed path 24 Reading transport path 25 Paper discharge path 27 Feeding roller 28 Feeding roller 29 Separating pad 30 Registration roller pair 32 First read roller pair 33 Second lead roller pair 34 Switching flapper 34a First pass surface 34b Second Pass surface 34c Third pass surface 35 Press roller 36 Rotating shaft 41 First switchback portion 42 Second switchback portion 43 First switchback roller pair 43a Drive roller 43b Follower roller 44 Second switchback roller pair 44a Drive roller 44b Follower Roller 45 first switch Back path 46 second switchback path 47 re-conveying path 48 wait roller pair 48a driven roller 48b driven roller 49 reverse discharge path 51 empty sensor 52 separated sensors 53 register sensor 54 read sensor 55 reverse sensor 56 reverse discharge sensor

Claims (2)

A paper feed tray on which documents are placed;
A transport means for transporting a document fed from a paper feed tray;
An image reading unit that reads both sides of the conveyed document;
A paper discharge tray that discharges the original that has been scanned on both sides;
A first switchback unit having a first switchback path for switching back a document whose surface has been read by the image reading unit and re-conveying the original to the image reading unit;
And a second switchback portion having a second switchback path for discharging the sheet discharge tray document having both surfaces read by the image reading unit switched back,
The first switchback unit sequentially switches back the document whose surface is read by the image reading unit and transports the document toward the image reading unit, and after switching back in the first switchback path. A document that is transported in a relatively reverse direction while rubbing the document and the document before switchback, and a document that is switched back in the second switchback path and a document whose surface is read by the image reading unit Are transported in the same direction with
The second switchback unit sequentially switches back the document whose other surfaces have been read by the image reading unit and conveys the document toward the paper discharge tray, and switches back in the second switchback path. An original conveying apparatus that conveys a subsequent original and an original before switchback in a relatively opposite direction while rubbing each other .   The first document and the next document transported from the paper feed tray are transported to the document reading unit in the order of the front surface of the first document and the front surface of the next document, and the two documents whose surfaces are read are transferred to the first switchback. The two originals are re-conveyed to the original reading unit in the order of the back side of the first original and the back side of the next original after being switched back by the second part, and the two originals having both sides read by the second switchback part The document conveying device according to claim 1, wherein the document conveying device is controlled so that the document is ejected to the sheet ejection tray after being switched back.

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