JP2011184120A - Document carrying device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a document carrying device surely carrying and discharging document, and having improved aligning performance of the discharged document, even when preceding document and succeeding document carried on a carriage passage one on top of the other have different lengths. <P>SOLUTION: The device includes: a carrier carrying document to the reading position; reversal discharger switching back the read document to reverse the document and send it; and paper discharger carrying the preceding document from the reversal discharger and the succeeding document from the carrier one on top of the other so as to discharge the preceding document onto a discharged paper tray and switch back the succeeding document to again send it to the reading position. The lengths of the preceding document and the succeeding document are compared to each other. When the length of the preceding document is longer than the length of the succeeding document, the succeeding document is made to stand by in the carriage passage. At the time point when the preceding document passes a predetermined position in the reversal discharge passage, the succeeding document is carried from the standby position. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a document conveying device that conveys a document to a predetermined reading position. More specifically, in order to read both sides of a document, the document which has been read on one side is switched back and conveyed to the reading position again. The present invention relates to document conveyance control for discharging a document.

    2. Description of the Related Art Image forming apparatuses such as copying machines and scanners use a document conveying device called an ADF (Auto Document Feeder) that conveys a document onto a platen glass of an image reading unit.

2. Description of the Related Art Conventionally, this type of document conveying apparatus includes a sheet feeding path for feeding a document on a sheet feeding tray to a reading position for reading a document, a conveyance path for receiving a document from the sheet feeding path and passing the reading position, and a reading path. The document that has been switched back on the paper discharge path by the paper discharge path for discharging the received document to the paper discharge tray and the paper discharge roller pair provided in the paper discharge path is received from the paper discharge path and guided again to the transport path. The document that has been scanned at the reading position is transported to a pair of paper discharge rollers, and after being switched back by this pair of paper discharge rollers, it is reversed through the circulation path and transported again to the reading position. However, there are some that read the back side of the document.

In the document conveying device configured as described above, it is necessary to reverse and discharge the document whose back side is read so that the page order is aligned on the discharge tray. For example, as in the case of reading the back side of a document as in Patent Document 1, after the document is switched back by a pair of discharge rollers, the document is conveyed through a reading position so that the front and back sides of the document are reversed and discharged from the discharge path. A structure for discharging to the discharge tray, a switchback path for switching back the document below the discharge tray, and a reversing path for guiding the document from the switchback path to the discharge path as in Patent Document 2 are provided. A configuration is known in which a document whose front and back sides are read at a reading position is switched back by a switchback path and then discharged to a discharge tray via a reverse path.

Further, Japanese Patent Laid-Open No. 2004-228561 has a configuration in which a preceding document and a succeeding document are transported in an overlapped manner in order to shorten the double-sided document reading process. In this configuration, in order to reverse the page alignment of the original whose both sides have been read, the next original is fed into the conveyance path when a predetermined amount of the original has been conveyed into the conveyance path. As a result, the first original and the next original are overlapped in a state shifted by a predetermined distance, and are conveyed on the conveyance path. Then, the two originals conveyed in an overlapped state are sent to the paper discharge path in that state, and a predetermined position where the trailing edge of the preceding original preceding the trailing edge of the next original has passed through the discharge roller pair. When the position reaches, the paper discharge roller pair is reversed. As a result, the first original is discharged onto the discharge tray, and the next original is switched back by the pair of discharge rollers.

JP 2006-327728 A JP 2004-175460 A

In Patent Document 1, the leading edge of the leading document is moved in the transportation direction with respect to the leading edge of the next document by feeding the next document into the transportation path when the leading document sent from the circulation path is transported by a predetermined amount in the transportation path. A predetermined distance is shifted. Then, by shifting the leading edge of the first document from the leading edge of the next document by a predetermined distance, the leading edge of the next document in the transport direction is nipped by the pair of discharging rollers when the leading document passes the pair of discharging rollers at the position of the pair of discharging rollers. It is in a state to do. However, when the document size of the next document following the previous document is smaller than the document size of the previous document, the trailing edge of the previous document is positioned downstream of the trailing edge of the next document in the paper discharge direction. The first original cannot be discharged onto the discharge tray and the next original cannot be switched back by the pair of discharge rollers.

The present invention has been made in view of the above-described problems, and reliably transports and discharges a document even if the length of the previous document and the next document that are transported over the transport path are different. It is an object of the present invention to provide a document conveying device that can perform the above processing.

  A conveying unit that conveys a document to a reading position, a reversing discharge unit that switches back a read document and reversely sends the document, a first document from the reversing discharge unit, and a next document from the conveying unit are overlapped. A paper discharge means for discharging the first original to a paper discharge tray and switching back the next original and sending it to the reading position again, comparing the length of the first original and the next original, When the length of the original is longer than the length of the next original, the next original is waited on the transport path, and the next original is transported from the standby position when the previous original passes a predetermined position on the reverse discharge path.

With this configuration, even when the length of the first original and the length of the next original are different, the first original conveyed by the paper discharge unit is surely discharged to the paper discharge tray and overlapped with the first original. The next original can be switched back reliably, and the effect of preventing a poor conveyance of the original is obtained.

1 is a cross-sectional view illustrating a configuration of a document conveying device according to the present invention and an image reading device equipped with the document conveying device. FIG. 3 is an enlarged cross-sectional view showing a main part of the document conveying device according to the present invention. FIG. 3 is a block diagram showing a control system of the document feeder according to the present invention. It is explanatory drawing which shows the flow of the original document of the original conveying apparatus which concerns on this invention. FIG. 6 is a state diagram illustrating a state where a document discharge operation and a switchback operation according to the present invention are performed simultaneously. FIG. 5 is an operation flowchart showing an original size detection operation according to the present invention. FIG. 10 is an operation flowchart illustrating a selection operation for selecting a transport discharge operation according to the document size according to the present invention. It is an operation | movement flowchart figure which shows the 1st conveyance discharge operation | movement which concerns on this invention. It is an operation | movement flowchart figure which shows the 2nd conveyance discharge operation | movement which concerns on this invention. FIG. 6 is a state diagram showing a transport state of a first document and a next document in a first transport / discharge operation according to the present invention. FIG. 10 is a state diagram illustrating a transport state of a first document and a next document in a second transport / discharge operation according to the present invention.

FIG. 1 is a cross-sectional view showing a configuration of an original conveying apparatus and an image reading apparatus on which the original conveying apparatus is mounted, and FIG. 2 is an enlarged cross-sectional view showing a main part of the original conveying apparatus. 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, a document conveying device 3 according to the present invention is attached to an upper side of an image reading device main body 2 having an image reading means so as to be opened and closed.

The image reading unit of the image reading apparatus main body 2 reads a document passing through the upper surface of the first contact glass 6 with the optical carriage 5 fixed. Further, a second contact glass 7 for placing a document is provided on the upper surface of the main body 2, and reading can be performed by moving the optical carriage 5 with respect to the document set on the contact glass 7. it can.

The optical carriage 5 includes a first carriage 10 having a lamp for irradiating light to the original and a first mirror for deflecting the direction of reflected light from the original, and a second guide for deflecting and guiding the direction of light from the first mirror. The second carriage 11 has a third mirror. Then, the lamp is irradiated with light to the original conveyed on the first contact glass 6 or the original placed on the second contact glass 7, and the reflected light of the original is reflected by the lens 16 through a plurality of mirrors. Condensate. The light condensed by the lens 16 is photoelectrically converted by a photoelectric conversion element 17 such as a CCD, and an original image is read.

Next, the configuration of the document conveying device 3 will be described. As shown in FIGS. 1 and 2, the document transport device 3 includes a paper feed tray 20 on which a plurality of documents can be placed, and a paper discharge tray 22 that stores a document that has been read. . In addition, the document transport device 3 receives a document from a sheet feeding unit provided with a sheet feeding path 23 for feeding documents from the sheet feeding tray 20 toward the first contact glass 6, and a document from the sheet feeding path 23. And a paper discharge path 25 for guiding a document from the transfer path 24 from the paper discharge port 41 to the paper discharge tray 22. The paper discharge section, the circulation section provided with the circulation path 45 that communicates the discharge path 25 and the paper feed path 23, and the paper discharge path 25 branch downstream from the first contact glass 6. And a reverse discharge path 49 that reverses the original from the switchback path 46 and guides the original from the switchback path 46 to the discharge port 41 side of the discharge path 25. And a discharge unit.

In the paper feeding section, a feeding roller 27 that feeds out the original on the paper feeding tray 20, a paper feeding roller 28 that feeds the fed out original, and press feeds against the paper feeding roller 28 to separate the originals one by one. A separation pad 29 and a pair of registration rollers 30 that are fed out after abutting and aligning the leading ends of the documents that are separated and fed one by one are fed along the sheet feeding path 23.

The transport unit transports the original from the registration roller pair 30 to the first contact glass 6 and the first lead roller pair 32 that feeds the original on the first contact glass 6 toward the downstream. 2 read roller pairs 33, and conveys the document along the conveyance path 24 through the upper surface of the first contact glass 6.

The paper discharge unit is provided with a pair of paper discharge rollers 43 for discharging the document onto the paper discharge tray 22. The pair of paper discharge rollers 43 functions to reverse from normal rotation with the rear end of the original in the paper discharge direction nipped, and switch the document back to transport it from the downstream side of the paper discharge path 25 to the circulation path 45. Is also used. The circulation unit is provided with a standby roller pair 48 for sending the document switched back by the paper discharge roller pair 43 to the paper feed path 23.

The reverse discharge portion is provided with a switchback roller pair 44 that switches back the document carried in the switchback path 46 and sends it to the reverse discharge path 49. The paper discharge roller pair 43 and the switchback roller pair 44 are configured such that the other roller is separated from one roller, and pressure contact / separation control is performed according to the conveyance state of the document.

Further, at the branch portion between the discharge path 25 and the switchback path 46 communicated from the transport path 24, the document from the second read roller pair 33 is fed to the discharge path 25 and the switchback path according to the reading process. A first flapper 34 for guiding one of the two to 46 is provided, and a document that is switched back by the pair of discharge rollers 43 is connected to the connection portion between the discharge path 25 and the circulation path 45. A second flapper 52 for guiding to 45 is provided. Further, a third flapper 53 for guiding the document switched back by the switchback roller pair 44 to the reverse discharge path 49 is provided in the reverse discharge unit. The second and third flappers 52 and 53 are supported so as to move downward under their own weight. As a result, the second flapper 52 is pushed upward by the original from the second lead roller 33 so that the original passes. When the original passes, the second flapper 52 moves downward to connect the discharge path 25 and the circulation path 49. . Similarly, the third flapper 53 is pushed upward by the original from the second lead roller 33 and passes through the original. When the original passes, the third flapper 53 moves downward to communicate the switchback path 46 and the reverse discharge path 49. Let

In addition, as shown in the block diagram of the control system in FIG. 3, various sensors are provided at various places where the document passes. An empty sensor S1 for detecting a document on the paper feed tray 21 is provided in the vicinity of the feeding roller 27, a registration sensor S2 and a lead sensor S3 are provided in the feeding path 23, and a discharge sensor S4 is provided in the discharge path 25. Yes. A reverse discharge sensor S5 is disposed in the reverse discharge path 49. Then, by detecting the originals of these sensors, the driving of the paper feed motor M1, the discharge motor M2, and the standby motor M3 is controlled by the control board on which the CPU is mounted, and the originals are conveyed.

The sheet feeding motor M1 is drivingly connected to the sheet feeding roller 28 and the registration roller pair 30 via electromagnetic clutches CL1 and CL2, and the discharging motor M2 is drivingly connected to the sheet discharging roller pair 43 and the switchback roller pair 44. Yes. The standby motor M3 is drivingly connected to the standby roller pair 48.

The first solenoid SOL1 moves the driven roller 43b away from the driven roller 43a of the paper discharge roller pair 43, and the first solenoid SOL1 moves the drive roller away from the driven roller of the switchback roller pair 44. Move to. As a result, the pressure contact and separation of the roller pairs 43 and 44 are controlled.

Next, the operation of the document conveying apparatus will be described based on the explanatory diagram showing the flow of the document in FIG. 4. The document on the sheet feeding tray 20 is guided from the sheet feeding path 23 to the conveying path 24 as shown by the solid line in FIG. 4. Then, the surface is read at the reading position X. The document whose surface has been read at the reading position is transported to the paper discharge path 25 as indicated by the broken line in FIG. 4, and after being switched back by the paper discharge roller pair 43 of this paper discharge path 25, is conveyed through the circulation path 45. Returning to the path 24, the paper is guided to the reading position X again while the front and back sides are reversed, and the back side of the document is read. The document whose both sides are read at the reading position X is guided to the switchback path 46 and switched back as indicated by a two-dot chain line in FIG. The switched-back document is guided to the downstream side of the discharge path 25 through the reverse discharge path 49 while being reversed, and is discharged from the discharge path 25 to the discharge tray 22.

This document conveying operation will be described in detail. When the empty sensor S1 first detects that a document is placed on the sheet feeding tray 20, the sheet feeding motor M1 is driven and when the electromagnetic clutch CL1 is turned on, the feeding roller. 27 and the paper feed roller 28 are driven to rotate. As a result, the uppermost document placed on the sheet feed tray 20 is sequentially fed out, and the document is separated into one sheet by the separation pad 29 and sent. It should be noted that the paper discharge roller pair 43 and the switchback roller pair 44 are moved away from each other by the initial operation at the start of document feeding, and the first flapper 34 is guided along the paper discharge path 25. Moved in any direction.

When the registration sensor S2 detects the leading edge of the document separated into one sheet, the leading edge of the first document abuts against the nip portion of the registration roller pair 30 by conveying the document by a predetermined amount from the point of detection. This aligns the leading edge of the document and removes the document skew.

Thereafter, the electromagnetic clutch CL2 is turned on, and the registration roller pair 30 is driven to rotate. Then, the original is conveyed on the first contact glass 6 by the registration roller pair 30 and the first and second lead roller pairs 32 and 33. When passing over the first platen glass 6, the surface of the document is read.

The document that has passed through the first platen glass 6 is guided along the paper discharge path 25 via the first flapper 34. When the trailing edge of the first document is detected by the registration sensor S2 while the leading edge of the first document is guided to the paper discharge path 25, the electromagnetic clutch CL2 is turned off and the registration roller pair 30 is stopped, and feeding of the second original is started by the feeding roller 27 and the paper feeding roller 28. The leading edge of the fed second document abuts against the nip portion of the registration roller pair 30 and is aligned.

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 second original is sent out toward the first platen glass 6. The above-mentioned predetermined time is a predetermined time for keeping the interval between the first document fed first and the second document constant.

On the other hand, when the leading edge of the first document is detected by the discharge sensor S4, the discharge motor M2 is driven to rotate forward, and the first solenoid SOL1 is turned on (sucked). As a result, the driven roller 43b of the discharge roller pair 43 is pressed against the drive roller 43a, and the first original is further conveyed toward the discharge tray 22 side.

While the second original is being conveyed toward the first platen glass 6, the first original that has passed through the first platen glass 6 has a certain time after the trailing edge is detected by the discharge sensor S4. When the discharge motor M2 is stopped, the paper is stopped while being nipped by the paper discharge roller pair 43. Thereafter, by rotating the discharge motor M2 in the reverse direction, the discharge roller pair 43 is driven in reverse rotation, and the first original is switched back.

Then, the first document switched back by the paper discharge roller pair 43 is conveyed along the first switchback path 45. Then, after the leading edge of the first document is nipped by the standby roller pair 48 that is driven to rotate, the standby motor M3 is stopped, whereby the first document is temporarily stopped. When the first document is nipped by the standby roller pair 48 and stopped, the first solenoid SOL1 is turned off (suction is released), the paper discharge roller pair 43 is separated, and the discharge motor M2 is switched to the normal rotation drive. .

In this state, the second original that has passed through the first contact glass 6 is conveyed to the discharge roller pair 43 along the discharge path 25. At this time, the second original is conveyed below the first original in the downstream portion of the discharge path 25. At this time, since the discharge roller pair 43 is separated, the leading edge of the second original is conveyed toward the discharge tray without any trouble. Further, since the drive roller 43a of the pair of separated paper discharge rollers 43 is driven to rotate in the forward direction, the second document is fed with a conveying force when the drive roller 43a comes into contact and is smoothly fed.

The electromagnetic clutch CL2 through which the second document passes the registration sensor S2 is turned OFF. Further, the standby motor M3 is driven after a predetermined time has elapsed since the trailing edge of the second document was detected by the registration sensor S2. As a result, the leading edge of the first document stopped in the paths 45 and 49 comes into contact with the registration roller pair 30 and is aligned. Thereafter, the electromagnetic clutch CL2 is turned on to rotationally drive the registration roller pair, and the first original is reversed and conveyed toward the first contact glass 6. During this time, the first original roller pair 32, the second read roller pair 33, and the paper discharge roller pair 43 are driven to rotate forward so that the second original passes the first original downstream of the discharge path. Are transported. At this time, the pair of paper discharge rollers 43 are transported in different directions for the first document and the second document in a separated state. Then, the first solenoid SOL1 is turned on after a lapse of time until the trailing edge of the second document reaches the reading position X of the first contact glass 6 after the lead sensor S3 detects the trailing edge of the second document. Turned on and the discharge roller pair 43 is pressed. As a result, the paper discharge roller pair 43 overlaps and presses the first and second originals, and the first and second originals are part of the discharge path 25 in this state. It will be transported in different directions. At this time, the friction coefficient of the driving roller 43a is set higher than that of the original and the driven roller 43b. As a result, the first document between the driven roller 43b and the second document is fed toward the reading position X by the standby roller 48, the registration roller pair 30, and the first read roller pair 43, and the driving roller. The second original between 43a and the first original is fed to the discharge tray 22 side against the first original by the conveying force of the driving roller 43b.

The discharge roller pair 43 is driven from the normal rotation drive to the reverse rotation by switching the discharge motor M2 from the normal rotation drive to the reverse rotation drive after a certain period of time after the trailing edge of the second document is detected by the discharge sensor S4. The second document is switched back. At this time, the trailing edge of the first document passes through the nip position of the discharge roller pair 43 and does not affect the switchback operation of the second document. The second document that has been switched back is conveyed along the first switchback path 45, and when nipped by the standby roller pair 48, the standby motor M3 is stopped. At the same time, the first solenoid SOL1 is turned off to stop and wait for the second original.

On the other hand, after the back side of the first document is read, the leading edge portion is guided to the second switchback path 46 through a path switched by the first flapper 34. The first flapper 34 forms a path that rotates clockwise to communicate with the switchback path 46 when the trailing edge of the second document is detected by the discharge sensor S4. When the rear end of the first document is detected by the read sensor S3, the second solenoid SOL2 is turned on (sucked), and the switchback roller 44 is brought into a pressure contact state.

The second document that is nipped by the standby roller pair 48 and waits is transferred to the registration roller pair 30 that is stopped by driving the standby motor M3 after the trailing edge of the first document is detected by the registration sensor S2. Abut. Thereby, the leading edge of the document is aligned. Then, by turning on the electromagnetic clutch CL <b> 2, the registration roller pair 30 is rotationally driven to re-feed the original toward the reading position X of the first contact glass 6.

When the trailing edge of the first document conveyed to the switchback path 46 is detected by the discharge sensor S4, the discharge motor M2 is switched from the reverse drive to the normal drive after a predetermined time. As a result, the switchback roller pair 44 switches from forward rotation to reverse rotation, and the first original is switched back. The first document that has been switched back is sent to the discharge roller pair 43 along the reverse discharge path 49, and is discharged to the discharge tray 22 by the discharge roller pair 43.

On the other hand, the second original is conveyed to the reading position X of the first contact glass 6 following the first original, the back surface is read, and conveyed to the switchback path 46. At this time, when the discharge sensor S4 detects the leading edge of the second original, the second solenoid SOL2 is turned OFF (adsorption release), and the second switchback roller 44 is separated. Then, the first document and the second document are conveyed so as to pass each other in the second switchback path. When it is detected that the second document has passed the registration sensor S2 during the conveyance process of the second document, the electromagnetic clutch CL1 is turned on. As a result, the feeding roller 27 and the paper feeding roller 28 are rotationally driven to start the feeding operation of the third original.

When the time until the trailing edge of the second document reaches the reading position X elapses after the trailing edge of the second document is detected by the read sensor S3, the second solenoid SOL2 is turned on and the switch is turned on. The back roller pair 44 comes into pressure contact. At the same time, the discharge motor M2 is switched from the forward rotation drive to the reverse rotation drive. At this time, the trailing edge of the first document passes through the switchback roller pair 44. As a result, the second original is switched back and sent to the paper discharge roller pair 43 along the reverse discharge path 49. Then, the paper is conveyed toward the paper discharge tray 22 by the paper discharge roller pair 43.

The leading edge of the third document is aligned by the registration roller pair 30 and is conveyed to the first contact glass 6 by the registration roller pair 30 and the first lead roller pair 32, like the first document. After the surface is read at the reading position X of the first contact glass 6, it is fed along the transport path 24 and the paper discharge path 25 by the second lead roller 33. Then, as shown in FIG. 5A, the third original is sent to the discharge roller pair 43 that is discharging the second original, and the second original as shown in FIG. 5B. Are conveyed toward the paper discharge tray 22 side. At this time, the trailing edge of the third document is conveyed in a state of being separated from the trailing edge of the second document by a predetermined distance L in a direction different from the direction of the paper discharge tray 22. Then, the discharge motor M2 is stopped after a predetermined time from the time when the trailing edge of the third document is detected by the discharge sensor S4. As a result, the paper discharge roller pair 43 is temporarily stopped. At this time, as shown in FIG. 5C, the second original is discharged to the paper discharge tray 22, and the third original has an end on the side different from the paper discharge tray 22 in the discharge roller pair 43. It stops in the state that was done. Then, by driving the discharge motor M2 in the reverse direction from this state, the discharge roller pair 43 is driven in the reverse rotation, and the third original is switched back. The paper discharge roller pair 43 is separated at the same time when the second original is switched back by the switchback roller pair 44, and is brought into pressure contact when the rear end of the third original reaches the reading position X. .

Thereafter, the subsequent fourth original passes through the reading position X, and is conveyed below the third original that is waiting in a state of being nipped by the standby roller pair 48 in the downstream portion of the discharge path 25. Thereafter, the third document is transported in the same manner as the previous first document, and the fourth document is transported in the same manner as the second document.

Here, as shown in FIGS. 5A, 5B, and 5C, when the second original is conveyed from the reverse discharge path to the discharge path, and the third original is sent from the transfer path to the discharge path. However, when a mixed document having different document sizes is handled, if the same control as that in the case of handling the same document size is executed, there is a problem that the conveyance failure of the document and the discharge alignment are deteriorated. That is, when the document size of the third document is smaller than the document size of the second document, the trailing edge of the second document is positioned downstream of the trailing edge of the next document in the paper discharge direction. Therefore, the second original cannot be discharged onto the discharge tray and the third original cannot be switched back by the discharge roller pair. If the document size of the third document is larger than the document size of the second document, the third document is moved to the switchback position even if the second document passes through the pair of paper discharge rollers. Since the two originals are difficult to be separated due to static electricity or the like, the second original is conveyed to a position far from the paper discharge port. As a result, the positions of the originals falling on the paper discharge tray vary, and the original alignment on the paper discharge tray decreases.

Therefore, in the present embodiment, the second read roller pair 33 and the switchback roller pair 44 are controlled to surely discharge the second original even if it is a mixed original, and the third original. Can be switched back, and the paper discharge alignment is good.

The operation when the second document and the third document are different in size will be described. For the sake of convenience, hereinafter, the second original is referred to as the first original D1, and the third original is referred to as the next original D2.

FIG. 6 is an operation flowchart for detecting the document size, and FIG. 7 is an operation flowchart for selecting the first and second transport / discharge operations according to the document size. FIG. 8 is an operation flowchart showing the first transport / discharge operation, and FIG. 9 is an operation flowchart showing the second transport / discharge operation. Further, FIG. 10 is a state diagram showing the transport state of the first document D1 and the next document D2 in the first transport / discharge operation, and FIG. 11 shows the transport state of the first document D1 and the next document D2 in the second transport / discharge operation. FIG.

First, the document size detection operation will be described with reference to FIG. In the process of transporting the document from the sheet feed tray 20 to the reading position X, the sheet feed motor M1 from the detection of the leading edge of the document to the detection of the trailing edge of the document by the registration sensor S2 provided in the sheet feeding path 23. The drive pulse is counted by the pulse counter CN, and the size of the original is discriminated from this count value (ST1 to ST5). On the other hand, before the registration sensor S2 detects the trailing edge of the document, the leading edge of the document is detected by the discharge sensor S4. Even when the leading edge of the document reaches a position conveyed by a predetermined amount from the detection of the discharge sensor S4, the registration sensor. If the trailing edge of the document is not detected in S2, the document size is determined based on the detection state of a plurality of width sensors (not shown) (ST3, ST6 to ST8). The determined document size is stored in the RAM for each document (ST9). A plurality of width sensors are arranged in the width direction orthogonal to the document conveying direction at the same position as the registration sensor S2. In the present embodiment, since a document having a predetermined size or larger is configured to be detected only by the document width, the document size can be specified from the document width detected by the width sensor. In other words, in the present embodiment, the document to be handled is set to the general sizes A5 horizontal, A5 vertical, A4 horizontal, A4 vertical, A3 vertical A series and B5 horizontal, B5 vertical, B4 vertical B series. Further, as shown in FIG. 10 (a), the distance La from the registration sensor S2 to the position P1 conveyed by a predetermined amount from the detection of the discharge sensor S4 is made longer than the horizontal length of A4. For this reason, there are four types of B4 vertical, A4 vertical, A3 vertical, and B4 vertical documents whose sizes cannot be detected by the registration sensor S2 when the leading edge of the document reaches the predetermined position P1. Since the document types have different document widths, the size can be easily determined by arranging a plurality of width sensors at positions corresponding to the respective sizes in the width direction.

Then, as shown in the flowchart of FIG. 7, the size of the previous document D1 and the size of the next document D2 stored in the RAM in the document size detection operation are compared, and the length of the size of the previous document D1 is the length of the size of the next document D2. If it is longer than this, the first transport and discharge operation is executed (ST11 to ST12). On the other hand, when the length of the size of the first document D1 is shorter than the length of the size of the next document D2, the second transport / discharge operation is executed (ST11, ST13). The first and second transport / discharge operations are executed after the leading edge of the next original D2 reaches the predetermined position P1 and the size of the next original D2 is determined by the original size detection operation.

The first transport and discharge operation when the length of the previous document D1 is longer than the length of the next document D2 will be described with reference to FIGS. 8 and 10. As shown in FIG. When the position P1 is reached, the front document D1 is switched back by the switchback path 46, and is transported by the switchback roller pair 44 toward the reverse discharge path. The first document D1 conveyed by the switchback roller pair 44 and the next document D2 conveyed by the first and second lead rollers 32 and 33 are conveyed in a state of being overlapped between the separated discharge roller pair 34. Is done.

In the first transport and discharge operation, first, the next document D2 is moved to a predetermined standby position P2 between the reading position X and the second pair of read rollers 33 from the time when the trailing edge of the next document D2 is detected by the read sensor S3. If the transport amount corresponding to the distance is transported, the paper feed motor M1 is stopped (ST21 to ST23). As a result, the second read roller pair 33 is stopped, and as shown in FIG. 10B, the subsequent end of the next original D2 stops at the predetermined position P1 and enters a standby state. In the present embodiment, the number of pulses corresponding to the transport amount of the document is set, and it is determined whether or not the document has been transported by a predetermined amount by counting the drive pulses of the paper feed motor M1 or the discharge motor M2. .

Then, at the same time as the paper feed motor M1 is stopped, the first solenoid SOL1 is turned on to press the paper discharge roller pair 43 (ST25). At this time, the first document D1 is sandwiched between the next document D2 and the drive roller 43a of the paper discharge roller pair 43, and is conveyed by the drive roller 43a. The next original D2 that is stopped by being sandwiched between the first original D1 and the driven roller 43b of the paper discharge roller pair 43 is nipped by the second read roller pair 33, and therefore does not follow the movement of the first original D1. Hold the stopped state.

Then, as shown in FIG. 10C, when the trailing edge of the front document D1 is detected by the reverse discharge sensor S5, the paper feed motor M1 is re-driven (ST25 to ST26). As a result, the second read roller pair 33 is driven, and the next original D2 is conveyed in the paper discharge direction together with the previous original D1. In this embodiment, as shown in FIG. 10C, the distance from the reverse discharge sensor S5 to the position of the paper discharge roller pair 43 and the position of the paper discharge roller pair 43 from the predetermined position P2 is larger than the distance L1 from the reverse discharge sensor S5 to the position of the paper discharge roller pair 43. The distance L2 is configured to be longer by the distance Lx. Accordingly, as shown in FIG. 10 (e), the trailing edge of the first document D1 is located at a distance Lx in the discharge direction with respect to the trailing edge of the next document D2, and the two documents are placed on the discharge roller pair 43. Are transported.

In the first transport and discharge operation described above, the next original D2 is made to wait at the standby position P2 of the transport path 24, and the next original D2 is re-transported from the stop position P2 when the trailing edge of the previous original D1 is detected by the discharge sensor S5. Therefore, even if the length of the first original D1 is longer than the length of the second original D2, the first original D1 is surely discharged onto the paper discharge tray 22, and only the second original D2 is switched back and conveyed. Can be sent to the circulation path 45.

Next, the second transport and discharge operation when the length of the first document D1 is shorter than the length of the next document D2 will be described with reference to FIG. 9 and FIG. 11. As shown in FIG. Similar to the discharge operation, when the leading edge of the next original D2 reaches the predetermined position P1, the front original D1 is conveyed along the reverse discharge path by the switchback roller pair 44, and thereafter, the front original D1 and the next original D2 Is conveyed in a state where it is overlapped between the pair of discharged paper discharge rollers 34.

In the process in which the original document D1 can be conveyed along the reverse discharge path by the switchback roller pair 44, the discharge motor M2 is turned on when the reverse discharge sensor S5 conveys a predetermined conveyance amount from the time when the leading edge of the front document D1 is detected. Stop (ST31 to ST33). At this time, as shown in FIG. 11B, the document conveyed by the switchback roller pair 44 stops when its trailing end reaches a predetermined standby position P3 near the downstream side in the discharge direction of the switchback roller pair 44. And enters a standby state.

Thereafter, after the trailing edge of the next original D2 is detected by the read sensor S3, the paper is fed after a conveyance amount corresponding to the distance from the reading position X to the predetermined stop position P2 between the second read roller pair 33. The paper motor M1 is stopped (ST34 to ST36). As a result, the second read roller pair 33 is stopped, and the trailing edge of the next original D2 is temporarily stopped at the predetermined standby position P2. At the same time, the first solenoid SOL1 is turned on, the discharge roller pair 43 is pressed, and the discharge motor M2 is driven forward again (ST37 to ST38). As a result, as shown in FIG. 11C, the switchback roller pair 44 and the paper discharge drive roller 43a are rotationally driven, and the original document D1 is conveyed by the switchback roller pair 44 and the paper discharge drive roller 43a. At this time, since the next original D2 is nipped by the second lead roller pair 33 as described above, it does not follow the movement of the previous original D1.

Then, as shown in FIG. 11D, when the trailing edge of the front document D1 is detected by the reverse discharge sensor S5, the paper feed motor M1 is re-driven (ST39 to ST40). As a result, the second read roller pair 33 is driven, and the next original D2 is conveyed in the paper discharge direction together with the previous original D1. At this time, the trailing edge of the first document D1 is located at a distance Lx in the sheet discharge direction as shown in FIG. 11E with respect to the trailing edge of the next document D2. Be transported.

Whether or not to execute the second conveyance / discharge operation is selected after the front document D1 passes through the reverse discharge sensor S5. Here, the leading edge of the front document D1 is detected in advance by the reverse discharge sensor S5, Counting is performed by the pulse counter CN of the number of drive pulses for quantitative conveyance, and when the first conveyance discharge operation is selected, the count value of the number of drive pulses is cleared. The predetermined amount is a conveyance amount corresponding to a length obtained by subtracting a certain length from the length of the size of the original document D1.

Further, in the above-described second transport and discharge operation, the first document D1 is made to wait at the standby position P3 of the switchback path 46, and when the next document D2 reaches a predetermined stop position P2 of the transport path 24, the first document D1 is loaded. The next original D2 is re-conveyed from the stop position P2 when the rear end of the first original D1 is detected by the discharge sensor S5. This is because when the next original D2 is read, that is, when the original passes through the reading position X, if the paper discharge roller pair 43 is pressed, the read image of the original is distorted, and the first original D1 passes through the switchback roller pair 44. It is controlled in consideration that it cannot stand by at the position. Therefore, for example, a roller pair is provided downstream of the reverse discharge sensor S5 in the reverse discharge path 49 and the standby position P3 is set to the position of the reverse discharge sensor S5 in the reverse discharge path 49. When the reverse discharge sensor S5 detects the trailing edge of the leading document D1, the leading document D1 is stopped and waited, and when the trailing edge of the next document D2 reaches a position P2 downstream of the reading position, the discharging roller. It is also possible to press the pair and re-carry the previous document D1 so that the previous document D1 and the next document D2 are overlapped and sent.

In the second transport and discharge operation described above, the first document D1 is made to wait at the standby position of the switchback path 46 or the reverse discharge path 49, and when the next document D2 reaches the predetermined position P2 of the transport path 24, the first document D1. Therefore, even if the length of the first document D1 is shorter than the length of the next document D2, it is possible to prevent the first document D1 from jumping out of the discharge roller pair 43 and to discharge the document. The paper alignment can be improved.

In the embodiment described above, the first surface, the second surface, the first back surface, the second back surface, the third surface, the fourth surface, the third back surface. The document transport operation was executed so that the document was read in the order of the back side of the fourth sheet, but the first side, the first side, the second side, the second side, the third side The document may be conveyed so as to be read in the order of the front surface, the third back surface, the fourth surface, and the fourth back surface. In this case, after reading the front surface of the first document at the reading position, the document is switched back at the paper discharge unit, re-conveyed to the reading position via the circulation unit, and reversely discharged after reading the back side of the document. The original is conveyed to the section. At this time, the next original is fed at the next point after the original passes through the registration sensor S2, and conveyed to the reading position following the previous original. The original document conveyed to the reverse discharge unit is switched back to the reverse discharge unit and sent to the paper discharge roller pair 43 of the paper discharge unit via the reverse discharge path 49. At the same time, the next original whose surface has been read at the reading position is also sent to the paper discharge roller pair 43 along the paper discharge path 25. Then, the first document and the next document are conveyed in a state where they overlap the downstream side of the sheet discharge path 25, the first document is discharged to the sheet discharge tray 22, and the next document is conveyed in a switchback manner. That is, according to the reading procedure of the above-described embodiment, the transport / discharge operation is controlled according to the trailing edge of the second document transported by the pair of discharge rollers 34 and the size of the third document. In this reading procedure, the conveying and discharging operations of the trailing edge of the first document and the second document are controlled.

According to the above-described embodiment, when the length of the previous original is longer than the length of the next original, the next original is waited in the middle of conveyance, and the next original in the standby state is based on the fact that the previous original has passed a predetermined position. When the original is transported and the length of the first original is shorter than the length of the next original, the first original is placed in the middle of discharge, and the next original waiting is conveyed based on the fact that the next original has passed a predetermined position. As a result, it is possible to reliably discharge the first original onto the paper discharge tray and switch back only the next original, and to improve the alignment of the original discharged to the discharge tray.

2 Image reading device 3 Document transport device 6 First contact glass 20 Paper feed tray 22 Paper discharge tray 23 Paper feed path 25 Paper discharge path 33 Second lead roller pair 43 Paper discharge roller pair 45 Circulation path 44 Switchback roller pair 46 Switchback path 49 Reverse discharge path S2 Registration sensor S3 Lead sensor S4 Discharge sensor S5 Reverse discharge sensor

Claims (5)

A paper feed tray for placing a document, a paper discharge tray for storing a document read at a reading position for reading the document, a paper feed unit for feeding a document on the paper feed tray toward the reading position, A transport unit that transports a document to the reading position, a paper discharge unit that discharges the read document onto a discharge tray, and a circulation for transporting the document read at the reading position to the reading position again. A document conveying apparatus comprising: a reversing discharge unit configured to reverse the read document and convey the document to the paper discharge unit;
A reversing discharge means for conveying the original document from the reverse discharge section to the paper discharge section provided in the reverse discharge section; a conveying means for conveying the original document from the transport section to the paper discharge section; An original provided from the reverse discharge unit and the original from the conveyance unit are provided in the paper discharge unit so as to be overlapped and conveyed, and the original from the reverse discharge unit is discharged and the original from the conveyance unit is switched back. A paper discharge unit that sends the paper to the circulation unit, a detection unit that is disposed upstream of the reading position, detects a document, a determination unit that determines the length of the document based on a detection result of the detection unit, and the determination The length of the next original transported to the reading position following the previous original and the previous original determined by the means is compared. If the length of the previous original is longer than the length of the next original, The next document transported to the discharge unit And the next document is transported from the standby position of the transport unit when the previous document transported from the reverse discharge unit to the discharge unit passes the predetermined position of the reverse discharge unit. As described above, a document conveying apparatus comprising: a conveying unit and a control unit that controls the reverse conveying unit. When the length of the previous document is shorter than the length of the next document, the control unit stops the previous document conveyed from the reverse discharge unit to the discharge unit at a predetermined standby position of the reverse discharge unit, Controls the conveying unit and the reverse conveying unit so that the next original conveyed from the conveying unit to the discharge unit passes the predetermined position of the conveying unit to convey the original document from the standby position of the reverse discharging unit. The document conveying device according to claim 1. The transport means includes a pair of transport rollers provided on the downstream side of the reading position,
The document conveying apparatus according to claim 1, wherein a standby position of the conveying unit is provided between the reading position and the pair of conveying rollers. The predetermined position of the reverse discharge unit is provided at a position where the distance from the predetermined position of the reverse discharge unit to the paper discharge unit is shorter than the distance from the standby position of the transport unit to the discharge unit. The document conveying device according to claim 1. The predetermined position of the transport unit is provided at a position where the distance from the predetermined position of the transport unit to the paper discharge unit is longer than the distance from the standby position of the reverse discharge unit to the discharge unit. The document conveying device according to claim 2.