JP3689081B2 - Document conveying apparatus, document conveying method, and image reading apparatus - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a document transport apparatus and a document transport method that are mounted on a copy apparatus, a facsimile machine, or the like, and transport a document to a predetermined reading position in order to read a document image, and in particular, read both front and back sides of a document continuously. The present invention relates to an original conveying apparatus and an original conveying method for discharging paper with the page order aligned without inverting the original surface.
[0002]
[Prior art]
[Patent Document 1]
JP 2001-354336 A
In many cases, an image reading apparatus for automatically and sequentially reading a plurality of originals is a transported original reading method (sheet-through reading method) in which an original is conveyed on a reading unit disposed at a predetermined reading position. ) Is used.
[0003]
In this case, the originals stacked on the paper feed tray are fed out one by one, read in a state rotated (reversed) by 180 degrees, and sequentially discharged onto the paper output tray. ) Are sequentially read, the page order of the originals that have been read and discharged onto the paper discharge tray as they are is maintained in the page order of the originals placed on the paper feed tray.
[0004]
However, when scanning both sides of a document, after scanning one side of the document, the document is reversed and the other side of the document is read continuously. When the paper is discharged, the page order of the originals discharged onto the discharge tray is overlapped with the original page surface of the original placed on the paper supply tray being reversed.
[0005]
For this reason, for example, in the conventional image reading apparatus disclosed in Patent Document 1, when both sides of a document are read, the page order of the document ejected on the sheet ejection tray is not reversed and is the same as the original. In order to align them, the original on which one side (front side) of the original is read, reversed, and read on the other side (rear side) is reversed again and fed over the reading position, and then the paper discharge tray The paper is discharged upward.
[0006]
[Problems to be solved by the invention]
In this way, when reading both sides of the document, in order to align the page order as it was without reversing the page order of the document ejected on the paper ejection tray, Since the operation of reversing the original is essential, the image reading apparatus disclosed in Patent Document 1 reverses the original on which both sides have been read and feeds the reading position to the paper discharge tray. Since the paper is used, the original is transported to the reading position three times for reading the front and back surfaces, which hinders the speeding up in the double-sided reading operation.
[0007]
The present invention has been made in view of the above-described problems, and enables a double-sided scanning operation that aligns the page order as it is without changing the page order of the read original, and at the same time, enables high-speed double-sided scanning. An object of the present invention is to provide an original document conveying apparatus and a document conveying method.
[0008]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention provides a paper feed tray on which a document is placed, and a paper feed that feeds the document placed on the paper feed tray one by one to a predetermined paper feed position. Means for conveying the fed document from the paper feed position to the paper discharge port via the reading position, and is provided in the paper discharge direction of the paper discharge port to switch back and reverse the document. Switchback path, a refeed path for guiding the document that has been switched back and reversed in the switchback path to the feed position again, and a document after image reading provided at the downstream end of the switchback path And a paper discharge means for discharging the paper onto a paper discharge tray, and the document that has been read on both sides is sent to the paper feed position via the switchback path, and is fed by the paper feed means. The document to be read next after being fed and the document that has been scanned on both sides are read at the reading position. It is conveyed in a stacked state, Conveyance for reading the document to be read next and conveyance for discharging the document after the double-sided reading to the paper discharge tray are performed simultaneously. An original conveying apparatus characterized by the above is provided.
[0009]
Here, by feeding the next document to be scanned and the next document that has been scanned for page alignment, the next document to be scanned is transported simultaneously and the document that has been scanned is fed simultaneously. Became possible. As a result, it is possible to perform a double-sided scanning operation in which the page order of the read original is aligned as it is without being reversed. Further, in order to read a double-sided document, it is necessary to transport the document to a three-time reading position. However, since the reading can be completed by two times of conveyance, the double-sided scanning operation can be speeded up.
[0010]
Further, the originals for which the duplex reading has been completed are stacked and conveyed in a state where the leading edge of the original is shifted a predetermined distance backward from the leading edge of the original to be read next at the paper feeding position. As a result, the next document to be read is stacked in a state shifted forward by a predetermined distance and conveyed to the reading position, and the document is always read from the next document to be read. The finished document is not read.
[0011]
Further, the paper discharge means includes a pair of paper discharge rollers that can be rotated at different rotational speeds in order to discharge the original on which the duplex reading has been completed to the paper discharge tray.
[0012]
The pair of paper discharge rollers includes a first paper discharge roller that comes into contact with a document that has been read on both sides of the stacked originals, and a second paper discharge roller that comes into contact with the next document to be read. When a document on which duplex reading has been completed is discharged onto the discharge tray, the first discharge roller is rotated at a higher speed than the second roller.
[0013]
As a result, at the position of the pair of paper discharge rollers, it is possible to transport the stacked originals on which the duplex reading has been completed to the paper discharge tray before the next original to be read.
[0014]
Further, the paper discharge roller pair switches back the original to be read next by reversing the rotation direction after detecting that the original on which the double-sided reading has been completed has passed through the paper discharge roller pair. The paper is sent to the paper feeding position.
[0015]
The pair of paper discharge rollers includes a reversing prevention lever that stops the back end of the original so that the original that has been read does not switch back when the rotation direction of the pair of paper discharge rollers is reversed. As a result, the document to be read next is switched back in order to read the back surface thereof, and the document that has been read and transported in advance at the position of the discharge roller is discharged to the discharge tray in the same page order. It became possible to make paper.
[0016]
The present invention further includes a step of feeding a document placed on a paper feed tray to a predetermined paper feed position, and transporting the fed document. Do A step of reading one side of the original transported to a predetermined reading position, a step of switching back and reversing the original on which the one side has been read, and a step of switching back and reversing the original A step of feeding the paper again to the paper feed position, a step of conveying the original on which the one side is read and reading the other side of the original, and a switchback of the original after the double-sided reading is reversed and inverting A step of feeding the original after completion of the double-sided reading to the paper feeding position, and conveying the original after completion of the double-sided reading through the reading position in a state of being overlapped with the next fed original. And a step of discharging the original after the double-sided reading, and the original after the double-sided reading is fed next. In a state of being superimposed on the manuscript Transport via the reading position In the step, a document reading method is provided in which one side of the next fed document is read.
[0017]
Here, by feeding the next document to be scanned and the next document that has been scanned for page alignment, the next document to be scanned is transported simultaneously and the document that has been scanned is fed simultaneously. Became possible. As a result, it is possible to perform a double-sided reading operation that aligns the page order as it is without changing the page order of the read document, and to speed up the double-sided scanning operation.
[0018]
Further, in the step of transporting the document that has been read on both sides via the reading position in a state of being overlapped with the document that is next fed, the document that has been read on both sides is Are conveyed rearwardly by a predetermined distance from the leading edge of the next fed document.
[0019]
As a result, the next document to be read is stacked in a state shifted forward by a predetermined distance and conveyed to the reading position, and the document is always read from the next document to be read. The finished document is not read.
[0020]
Further, after the step of discharging the original that has been read on both sides, the step of switching back the original on which one side of the next fed document is read and sending it to the feeding position; And reading one side of the original that has been read on one side.
[0021]
Also The present invention replaces the front and rear of a document read at the reading position, a conveying unit that feeds the document one by one and conveys it to a predetermined reading position, a reading unit that reads a document image that moves at the reading position, and A switchback path that reverses the front and back and re-feeds the original to the reading position, and a paper discharge unit that discharges the read original, and conveys the original from the reading position to the switchback path twice. Said The original front and back by the reading means Both sides Read Both sides A control unit is provided that superimposes the document that has been read and the next fed document and transports them to the reading position, and reads the next fed document that has been transported superimposed by the reading unit. An image reading apparatus is provided.
[0022]
The control unit conveys the document twice from the reading position to the switchback path, reads the front and back of the document by the reading unit, and then reads the document that has been read and the next fed document. The control unit reads the next fed document that is superposed and conveyed to the reading position and reads the next fed document by the reading unit, and conveys the document twice from the reading position to the switchback path. It is possible to select and perform control of reading the front and back sides of the original, further reversing the original that has been read and discharging the original by the paper discharge means, and then reading the supplied paper.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
The details of the document conveying apparatus and the document conveying method according to the present invention will be described below with reference to the drawings.
[0024]
FIG. 1 is a longitudinal sectional view of an automatic document feeder showing an embodiment of the document feeder of the present invention, showing a state where the automatic document feeder is mounted on an image reading device, and FIG. 2 is a main part of the automatic document feeder. FIG.
[0025]
In FIG. 1, reference numeral 10 denotes an automatic document feeder (hereinafter referred to as “ADF 10”) mounted on the image reading apparatus main body 1, and the ADF 10 is an upper surface of the first platen 2 of the image reading apparatus main body 1 (FIG. 1). The document is conveyed so as to pass through. The apparatus main body 1 irradiates a conveyed original with light from a light source 3 such as a lamp via a first platen 2, reflects the reflected light on a mirror 4, and photoelectrically converts the original by a reading unit such as a CCD. Read the image. That is, the upper surface of the first platen 2 constitutes a reading unit of the apparatus main body 1. The apparatus main body 1 also includes a second platen 5 having an area on which a document can be placed. The document placed on the upper surface of the second platen 5 by opening and closing the ADF 10 includes a light source 3 and a mirror 4. By moving the light source unit in the sub-scanning direction, an image of the document can be read through the second platen 5.
[0026]
The ADF 10 includes a paper feed tray 15 on which a plurality of originals can be placed, and a paper feed unit (paper feed means) that separates the originals on the paper feed tray 15 one by one and feeds them toward the first platen 2. ) 11, a transport unit (transport unit) 12 that passes the original along the upper surface of the first platen 2, and a paper discharge unit (paper discharge unit) 13 that receives and discharges the original that has passed through the upper surface of the first platen 2. And a paper discharge tray 16 for storing a document from which an image discharged from the paper discharge unit 13 is read. Further, the ADF 10 is configured to switch back a document discharged from the upper surface of the first platen 2 by the paper discharge unit 13, and send the document to the paper feeding unit 11 again to be fed to the upper surface of the first platen 2. And a paper re-feed path 30. Here, the paper feed tray 15 is inclined at a certain angle and is disposed with a space above the paper discharge tray 16.
[0027]
The side of the original placed on the paper feed tray 15 is regulated by the side guide 17 and the leading end is regulated by the stopper 60. Further, the paper feed tray 15 is rotatably attached with the front side 15a of the placed document as a fulcrum.
[0028]
The paper feed unit 11 descends and comes into contact with the uppermost surface of the original on the paper feed tray 15, and an up and down feed roller 18 that feeds the original, and a paper feed roller 19 that feeds the original fed by the feed roller 18 and the uppermost roller. Separation means composed of a separation pad 20 that passes only one upper document and blocks the feeding of the second and subsequent documents, and abuts the leading edge of the document separated into one by this separation means It consists of a pair of registration rollers 21 that are sent to the downstream side after alignment, and feeds the original along the paper feed path 25.
[0029]
The transport unit 12 includes a pair of transport rollers 22 for supplying a document to the first platen 2 on the upstream side of the first platen 2, and a pair of transport rollers 23 for discharging the document from the first platen 2 on the downstream side. The document is conveyed along a conveyance path 26 formed by the first platen 2 and the scooping guide 6 on the main body 1 side and the backup guide 26a on the ADF 10 side.
[0030]
The paper discharge unit 13 and the switchback unit 14 share a part on the paper discharge tray 16 side, and are provided with a paper discharge roller pair 24 that discharges the original to the paper discharge tray 16. As will be described later, the paper discharge roller pair 24 is controlled so as to reversely rotate in a state where the rear end side of the original is nipped in the double-sided reading mode, and to switch back the original and send it to the paper supply unit 11. .
[0031]
Further, the pair of paper discharge rollers 24 can be transported without any trouble when the leading and trailing ends of the documents circulated from the switchback unit 14 through the paper discharge unit 13, the refeed path 30, and the transport unit 12 pass each other. The sheet discharge roller 24b (second sheet discharge roller) is separated from the sheet 24a (first sheet discharge roller).
[0032]
In addition, a switchback path 28 and a flapper 29 for guiding the document to the paper discharge unit 13 are provided in a shared part of the paper discharge unit 13 and the switchback unit 14. The flapper 29 is always biased downward by a biasing spring (not shown), and the pair of paper discharge rollers 24 passes through a paper discharge port 31 where the original merges with the switchback path 28 along the paper discharge path 27. When the document is sent to the printer, the document is pushed upward by the leading edge of the document to be discharged and allows the document to pass therethrough. Further, when the document is switched back by the pair of discharge rollers 24, the document is positioned below to close the discharge path 27 and guide the document to the switchback path 28.
[0033]
The paper discharge path 27 is formed by a paper discharge upper guide 27 a extending from a backup guide 26 a provided to face the first platen 2, and a paper discharge lower guide 27 b formed integrally with the paper discharge tray 16. ing. The switchback path 28 refeeds the document by a switchback upper guide 28 a (FIG. 2) provided continuously on the document guide surface of the flapper 29 and a sheet discharge lower guide 27 b extending from the sheet discharge path 27. It is formed so as to guide to the road 30. The re-feeding path 30 is provided continuously from the switchback path 28, and the switchback upper guide 28a and the switchback lower guide 28b are used to feed the document to the feeding position of the registration roller pair 21 (hereinafter referred to as "nip point"). It is formed to guide.
[0034]
That is, the re-feed path 30 and the feed path 25 are configured to join at the nip point of the registration roller pair 21, and the mylar 28 c that draws the original document at the nip point of the registration roller pair 21 at this joining position. Is extended.
[0035]
Next, the driving configuration of each roller will be described with reference to FIGS. The ADF 10 is configured such that each roller is driven by a feed motor M1 and a transport motor M2 that can freely rotate forward and backward. FIG. 3 shows a drive transmission system of the feed motor M1, and FIG. These show the drive transmission system of the conveyance motor M2.
[0036]
First, as shown in FIG. 3, the drive transmission system of the paper feed motor M1 transmits the forward rotation drive of the paper feed motor M1 from the pulley P16 to the pulley P36 via the timing belt T16, and the drive of the pulley P36 is driven by the gear Z17, The gear Z19 and the gear Z18 attached to the drive shaft of the paper feed roller 19 are transmitted in this order, and the paper feed roller 19 rotates in the direction of feeding the document.
[0037]
A pulley P18 is provided on the drive shaft of the paper feed roller 19, and the drive is also transmitted to the feed roller 18 via a timing belt T2 stretched between the pulley P11 provided on the shaft of the feed roller 18. Is done.
[0038]
One end side of an elevating arm 18a that supports the feeding roller 18 is attached to the drive shaft of the paper feed roller 19, and the drive shaft is moved up and down by rotation in the paper feed direction (forward drive of the paper feed motor M1). When the arm 18a rotates and the feeding roller 18 descends and the feeding roller comes into contact with the document, the drive shaft of the paper feeding roller 19 is idled with respect to the lifting arm 18a by the action of the spring clutch A and the spring clutch B. It is composed.
[0039]
At this time, the registration roller 21a is connected by a pulley P28 provided on the drive shaft and a timing belt T3 stretched on a pulley P22 provided coaxially with the pulley P36, but provided in the pulley P28. It does not rotate due to the action of the one-way clutch OW1.
[0040]
The reverse rotation driving of the sheet feeding motor M1 is transmitted from the pulley P16 to the pulley P36 via the timing belt T16, and attached to the shaft of the registration roller 21a from the pulley 22 provided coaxially with the pulley P36 via the timing belt T3. This is transmitted to the pulley P28, and the registration roller 21a is rotated in the paper feeding direction.
[0041]
At this time, the reverse drive of the paper feed motor M1 is also transmitted to the drive shaft of the paper feed roller 19, and the feeding arm 18 is raised by rotating the lifting arm 18a counterclockwise. The one-way clutch OW2 provided inside does not rotate. The raised lifting arm abuts against a regulating member (not shown), and the drive shaft of the sheet feeding roller 19 is configured to idle with respect to the lifting arm 18a by the action of the spring clutch C.
[0042]
Next, as shown in FIG. 4, the drive transmission system of the conveyance motor M2 transmits drive from the pulley P26 provided on the drive shaft to the pulley P46 via the timing belt T4, and is provided coaxially with the pulley P46. Drive is transmitted from the pulley P33 to the pulley P32 attached to the shaft of the transport roller 23a via the timing belt T6, and the transport roller 23a is rotated forward or reverse.
[0043]
Further, the drive transmitted to the pulley P32 is transmitted to the gear Z2 by the gear Z1 provided coaxially, and the transport roller 23b is rotated via the spring clutch C. The peripheral speed of the transport roller 23a and the set peripheral speed of the transport roller 23b are the same speed, but when the peripheral speed difference between the transport roller 23a and the transport roller 23b occurs, the peripheral speed difference is absorbed by the action of the spring clutch C. .
[0044]
Further, the drive transmitted to the pulley P32 is configured such that the drive is transmitted to the pulley P31 attached to the shaft of the transport roller 22a via the timing belt T7 so that the transport roller 22a is rotated forward or reverse. Yes. Further, the drive transmitted to the pulley P31 is transmitted to the gear Z4 by a gear Z3 provided coaxially, and the transport roller 22b is rotated via the spring clutch D.
[0045]
The peripheral speed of the transport roller 22a and the set peripheral speed of the transport roller 22b are the same, but when the peripheral speed difference between the transport roller 22a and the transport roller 22b occurs, the peripheral speed difference is absorbed by the action of the spring clutch D. .
[0046]
Further, the driving of the conveying motor M2 transmitted to the pulley P46 via the timing belt T4 is transmitted from the pulley P42 provided coaxially with the pulley P46 to the pulley P48 via the timing belt T5, and the paper discharge roller 24a. The paper discharge roller 24a (first paper discharge roller) attached to the shaft via the spring clutch E is rotated forward or reverse.
[0047]
Further, the drive transmitted to the pulley P48 is transmitted to Z6 by a gear Z5 provided coaxially to rotate the paper discharge roller 24b (second paper discharge roller). The peripheral speed of the transport roller 23a and the set peripheral speed of the paper discharge roller 24b are the same. The set peripheral speed of the paper discharge roller 24a is faster than that of the paper discharge roller 24b. When one sheet is nipped between the paper discharge roller 24a and the paper discharge roller 24b, or when there is no paper, the spring clutch E works. The paper discharge roller 24a follows the peripheral speed of the paper discharge roller 24b.
[0048]
Further, a pressure contact solenoid SOL as a drive source for separating the paper discharge roller pair 24 is provided. This pressure contact solenoid SOL moves the paper discharge roller 24b to a position where it comes into pressure contact with the paper discharge roller 24a by exciting (ON) the pressure contact solenoid SOL. Then, by releasing (OFF) the excitation, the discharge roller 24b is moved to a position away from the discharge roller 24a by the action of a biasing spring that urges the discharge roller 24b away from the discharge roller 24a. It is configured.
[0049]
The paper discharge roller 24a is provided with a reverse return preventing lever 35 coaxially via a spring clutch F.
[0050]
When the paper discharge roller 24a is rotated in the discharge direction (counterclockwise), the reverse prevention lever 35 is stopped at an upper position retracted from the discharge port. In rotation in the switchback direction (clockwise direction), the reverse prevention lever 35 descends to the paper discharge port, and hits the upper surface of the switchback paper and slips and stops by the spring clutch F, thereby preventing the reverse of the discharged original.
[0051]
The paper feed tray 15 is provided with a plurality of sensors S1, S2, and S3 (FIG. 1) in the document feed direction. The length of the document placed on is detected. Further, the width direction of the document placed on the paper feed tray 15 is detected from a volume (not shown) whose output changes depending on the amount of movement of the side guide 17, and the detection result of the document width and a plurality of sensors S1, The document size is determined based on the document length detected in S2 and S3.
[0052]
As shown in FIGS. 1 and 7, an empty sensor S4 for detecting that a document is placed on the paper feed tray 15 and a paper feed path 25 are fed into the route for guiding the document. A registration sensor S5 that detects the edge of the document, a lead sensor S6 that is provided in front of the first platen 2 to detect the edge of the document, and a discharge sensor that detects the edge of the document discharged from the first platen 2. S7 is provided.
[0053]
Here, as shown in FIG. 5, a lever-type sensor is adopted as the lead sensor S <b> 6, and the lead sensor S <b> 6 is disposed at a curved portion of the paper feed path 25. A protruding portion 25c formed of a plurality of ribs is provided at the document detection position of the lower sheet feeding guide 25b of the lead sensor S6.
[0054]
A sensor lever S6a of the lead sensor S6 is extended in the paper feed path 25 provided with the protruding portion 25c. The projecting portion 25c corrects the leading edge of the document and guides the document at a narrow distance from the paper feed upper guide 25a, so that the timing of detecting the leading edge of the document does not vary.
[0055]
Each of these sensors S1 to S7 is connected to a CPU that controls the driving of the entire apparatus. Based on the detection signal from each sensor, each of the motors M1 and M2 described above is driven and excitation of the press contact solenoid SOL is performed. Is made.
[0056]
Next, the document conveyance control operation of the ADF 10 having the above configuration will be specifically described in the first embodiment. Note that FIG. 6 to FIG. 12 schematically showing the document conveyance state are referred to as necessary. Further, the reference numerals shown in the triangles attached to the original D1 and the original D2 shown in the drawing indicate the page of the original.
[0057]
First, a description will be given of a single-sided reading mode for reading one side of a document. When the empty sensor S4 is in an ON state, that is, when it is detected that a document is placed on the paper feed tray 15, the paper feed motor M1 is driven forward. The first document D1 is fed. At this time, the feeding roller 18 and the paper feeding roller 19 are rotated in the document feeding direction, but the registration roller pair 21 is not rotated by the action of the one-way clutch OW1.
[0058]
When the registration sensor S5 detects the leading edge of the fed document, the paper feeding motor M1 is temporarily stopped after a predetermined time from the detection. When the paper feed motor M1 is stopped, the leading edge of the document is abutted against the nip portion of the registration roller pair 21 to form a deflection, and the leading edge of the document is aligned and the skew is removed (see FIG. 6A).
[0059]
After this stop, the paper feed motor M1 is driven in reverse, the transport motor M2 is driven, and the pressure contact solenoid SOL is further excited. At this time, the feeding roller 18 rises to a position away from the document, the drive of the paper feed roller 19 is cut off by the action of the one-way clutch OW1, and the registration roller 21a of the registration roller pair 21 is rotated in the document feeding direction.
[0060]
By the rotational driving of the motors M1 and M2, the document D1 is transported from the paper feed path 25 to the transport path 26, and after the lead sensor S6 detects the passage of the leading edge of the document D1, the paper feed motor M1 passes after a predetermined time. The conveyance motor M2 is temporarily stopped (see FIG. 6B).
[0061]
When the reading conveyance signal is received from the image reading apparatus main body 1, the conveyance motor M2 is driven again. The surface (one side) of the document D1 is sub-scanned and read by the reading means. At this time, the document D1 is conveyed onto the paper discharge tray 16 by pushing up the front end of the flapper 29 disposed so as to block the paper discharge path 27 at the front end.
[0062]
When the registration sensor S5 detects passage of the trailing edge of the document D1 after the document D1 is sent out, it checks whether there is a next document in the paper feed tray 15, and if there is a document in the paper feed tray 15, 1 The feeding operation of the second document D2 is started in the same manner as the second document D1.
[0063]
When feeding the second document D2, as in the case of the previous document, the feeding roller 18 and the feed roller 19 are rotated by the forward drive of the paper feed motor M1, and the document D2 is brought to the nip point of the registration roller pair 21. The skew is removed by abutting (see FIG. 6C). Further, the paper feed motor M1 is driven in reverse, and the drive of the paper feed motor M1 is stopped a predetermined time after the lead sensor S6 detects the leading edge of the next original, and the transport motor M2 is also stopped.
[0064]
Here, the leading edge of the document D2 is stopped before the first platen 2, and the first document D1 is nipped by the paper discharge roller pair 24 at the rear end. Stop (see FIG. 7D).
[0065]
When the reading conveyance signal is received from the image reading apparatus main body 1, the conveyance motor M2 is driven again. The surface of the document D2 is sub-scanned and read by the reading means described above. During the reading of the second original D2, the first original D1 is discharged onto the discharge tray 16 (see FIG. 7E).
[0066]
When the registration sensor S5 detects passage of the trailing edge of the document D2, it is checked whether or not the empty sensor S4 detects the presence of the next document, and if there is, the same 3 as the second document D2. The feeding operation of the first document D3 is started. Thereafter, as long as the empty sensor S4 detects the presence of a document, the same processing is performed on the documents D4, D5,.
[0067]
Note that the drive of the conveyance motor M2 is stopped after the time required for the last document to be discharged to the discharge tray 16 after the discharge sensor S7 detects the trailing edge of the last document, and the pressure contact solenoid SOL is excited. The processing of all originals is completed.
[0068]
Next, the double-sided reading mode will be described. For document reading, it is selected whether high-speed reading or high-precision reading is performed. This selection is performed by a selection switch (not shown). Hereinafter, reading performed by high-speed reading will be described.
[0069]
First, reading of the first double-sided scanned original will be described. When the empty sensor S4 detects that an original is placed on the paper feed tray 15, the first original D1 is fed forward by the feed roller 18 and the paper feed by the forward drive of the paper feed motor M1 as in the single-sided reading mode. The roller 19 is rotated so that the original is brought into contact with the nip point of the registration roller pair 21 to remove the skew.
[0070]
The document D1 conveyed by the reverse rotation drive of the paper feed motor M1 and the forward rotation drive of the carry motor M2 is detected by the lead sensor S6, and then the paper feed motor M1 and the carry motor M2 are temporarily stopped. The document D1 is in a state where the leading end position is stopped before the first platen 2. At this time, the pressure contact solenoid SOL is excited and the paper discharge roller pair 24 is pressure contacted (see FIG. 8A).
[0071]
When the reading conveyance signal is received from the image reading apparatus main body 1, the conveyance motor M2 is driven to rotate forward, so that the surface of the document is sent onto the first platen 2 and sub-scanned and read by the reading means. The document D1 read by the first platen 2 is guided to the paper discharge path 27.
[0072]
The document D1 guided from the paper discharge path 27 to the paper discharge port 31 is conveyed onto the paper discharge tray 16 by pushing up the front end of the flapper 29 disposed so as to block the paper discharge port 31 at the front end. In this conveyance state, when the time required for the trailing edge of the document D1 to pass the position of the flapper 29 has elapsed after the paper discharge sensor S7 detects the trailing edge of the document D1, the driving of the conveyance motor M2 is stopped, and the document In D1, the rear end side is nipped by the discharge roller pair 24 and stops (see FIG. 8B).
[0073]
Thereafter, the transport motor M2 is driven in reverse. As a result, the paper discharge roller 24a rotates in the reverse direction, the original D1 is switched back, and the paper is returned from the switchback path 28 along the original guide surface of the flapper 29 that has moved to a position that closes the paper discharge outlet 31 as the original passes. Guided to the paper feed path 30. The conveyance motor M2, which is driven in reverse, removes the skew because the deflection of the registration roller pair 21 is formed after the leading edge of the document D1 guided to the refeed path 30 is detected by the registration sensor S5. Then, it is stopped after a predetermined time (see FIG. 8C).
[0074]
Then, the paper feed motor M1 is driven in reverse to re-feed the original D1. The registration roller 21a is rotated in the sheet feeding direction by the reverse rotation driving of the sheet feeding motor M1, and after the time that the leading edge of the document D1 securely nips the registration roller pair 21, the excitation of the pressure contact solenoid SOL is released, and the sheet discharge driven roller 24b is moved downward to be separated from the paper discharge roller 24a, and the transport motor M2 is driven forward.
[0075]
When the document D1 is reversed and fed along the paper feed path 25 and the leading edge thereof is detected by the lead sensor S6, the transport motor M2 stops after a predetermined time and also stops the paper feed motor M1. Thereafter, the conveyance motor M2 is re-driven by the reading conveyance signal from the image reading apparatus main body 1, and the back surface of the document D1 is sub-scanned and read by the reading unit. At this time, the leading edge side of the document D1 sent to the sheet discharge tray 16 and the trailing edge side of the document D1 to be fed again pass at a common portion of the sheet discharge path 27 including the sheet discharge roller pair 24 and the switchback path 28. However, since the discharge roller pair 24 is in a separated state, it can be transported without any problem (see FIG. 9D).
[0076]
Thereafter, when the registration sensor S5 detects the trailing edge of the document D1, the pressure contact solenoid SOL is excited, the discharge roller pair 24 is pressed, and a predetermined time after the discharge sensor S7 detects the trailing edge of the document D1. When the time elapses, the driving of the transport motor M2 stops, and the document D1 stops with its trailing end being nipped by the paper discharge roller pair 24 (see FIG. 9E).
[0077]
Next, when the registration sensor S5 detects passage of the trailing edge of the document D1, it is checked whether or not the empty sensor S4 detects the presence of the next document. If there is, the second document D2 is detected. Start feeding operation.
[0078]
In the same way as the first sheet, the second sheet D2 is rotated by the forward rotation of the sheet feeding motor M1 to rotate the feeding roller 18 and the sheet feeding roller 19, and the document is brought into contact with the nip point of the registration roller pair 21 to remove the skew. Then, the document D2 conveyed by the reverse rotation drive of the paper feed motor M1 and the forward rotation drive of the conveyance motor M2 has a leading end that is a predetermined distance from the registration roller pair 21 (a distance of “Z” shown in FIG. 10B). It is transported and temporarily stopped (see FIG. 11A).
[0079]
Then, the document D1 is reversed 180 degrees and fed to the paper discharge tray 16 so as to be discharged in the same page order. Therefore, the transport motor M2 is driven in reverse and the skew is removed by abutting the leading edge of the document D1 against the nip portion (sheet feeding position) of the registration roller pair 21 in the refeed path 30 (see FIG. 10B) The leading edge misalignment between D2 and document D1 is the distance "Z" shown in the figure).
[0080]
Two sheets of the document D2 are simultaneously fed in a state of being overlapped with the document D1 by the reverse rotation driving of the sheet feeding motor M1 and the forward driving of the conveyance motor M2, and the driving of the sheet feeding motor M1 is stopped by detecting the leading edge of the document D2 of the lead sensor S6. To do. After the leading edge of the document D2 is detected by the read sensor S6, the paper feed motor M1 and the transport motor M2 are temporarily stopped, and the leading edge of the document D2 is stopped in front of the first platen 2. At this time, the pressure contact solenoid SOL is excited and the paper discharge roller pair 24 is pressure contacted (see FIG. 10C).
[0081]
When a reading conveyance signal is received from the image reading apparatus main body 1, the conveyance motor M2 is driven to rotate forward, whereby the surface of the document D2 is sent onto the first platen 2 and sub-scanned and read by the reading means. .
[0082]
At this time, the image data for determination of the surface of the document D1 previously read and stored in the read data storage unit (for example, the reverse image data of the surface image of the document D1) is being read while being shifted by the same amount as the shift amount Z. The image data of the original D2 is collated. If it is determined that the front image of the fed document D1 being fed through is showing through, a warning is given to the operator, and the operator cancels, forces, responds by image data correction, or The conveyance of the state in which the two originals are overlapped is stopped, and a process such as performing an empty feed only for the reversal performed in the prior art to prevent the original from being shown through is performed.
[0083]
The document D1 conveyed while being superimposed on the document D2 read by the first platen 2 is guided to the paper discharge path 27.
[0084]
The document D1 being conveyed while being overlapped with the document D2 guided from the paper discharge path 27 to the paper discharge port 31 has the front end of the flapper 29 disposed so as to block the paper discharge port 31 with the front end of the document D2. The paper is pushed up and conveyed onto the paper discharge tray 16. When it is detected in this transport state that the trailing edge of the document D1 has passed the transport roller pair 23, the document D1 is discharged at the peripheral speed of the discharge roller 24a (first discharge roller). It is conveyed at the peripheral speed of the roller 24b (second paper discharge roller) (see FIG. 11D).
[0085]
Here, the setting of the conveyance speed of the originals D1 and D2 can be expressed as follows.
[0086]
The peripheral speed of the paper discharge roller 24a is V1, and the peripheral speed of the paper discharge roller 24b is V2. The amount of misalignment between the document D1 and the document D2 is Z, the distance from the transport roller pair 23 through the flapper 29 (switchable position) is L, and the distance between the flapper 29 passing position and the reverse prevention lever 35 is H. To do.
V1 ≧ V2 (L + H) / (L−Z)
With the above setting, when the trailing edge of the document D2 reaches the switchback position, the trailing edge of the document D1 reaches the reverse prevention lever 35.
[0087]
When the time required for the trailing edge of the document D1 to pass through the position of the reverse return prevention lever 35 provided downstream of the flapper 29 after the discharge sensor S7 detects the trailing edge of the document D1, the transport motor M2 is driven. The document D2 is stopped, and the rear end side of the document D2 is nipped by the discharge roller pair 24 and stopped (see FIGS. 11E and 11F).
[0088]
Thereafter, the transport motor M2 is driven in reverse. As a result, the paper discharge rollers 24a and 24b rotate in the reverse direction, the original D1 is stopped by the reverse return prevention lever 35, only the original D2 is switched back, and the flapper moved to a position that closes the discharge outlet 31 as the original D2 passes. It is guided to the switchback path 28 along the document guide surface 29 (see FIG. 12G).
[0089]
The conveyance motor M2 that is driven in the reverse direction is bent at the nip portion of the registration roller pair 21 after the leading edge of the document D2 guided from the switchback path 28 to the refeed path 30 is detected by the registration sensor S5. Then, the skew is removed and stopped after a predetermined time.
[0090]
Then, the paper feed motor M1 is driven in reverse to re-feed the original D2. The registration roller 21a is rotated in the paper feeding direction by the reverse rotation of the paper feeding motor M1, and after the time for which the leading edge of the document D1 securely nips the registration roller pair 21, the excitation of the pressure contact solenoid SOL is released, and the paper ejection roller 24b. Is moved downward to move away from the paper discharge roller 24a, and the transport motor M2 is rotated forward. When the trailing edge of the document D2 passes the reverse prevention lever 35, the trailing edge of the document D1 that has been stopped by the reverse prevention lever 35 falls to the paper discharge tray 16 to complete the discharge (see FIG. 12 (h)). The back side of the document D2 conveyed to the conveyance path 26 is read.
[0091]
When the registration sensor S5 detects passage of the trailing edge of the document D2, it is checked whether or not the empty sensor S4 detects the presence of the next document, and if there is, the same 3 as the second document D2. The feeding operation of the first document D3 is started. The reading operation of the third document D3 is performed by repeating the operations shown in FIGS. 10 (a) to 12 (h).
[0092]
Thereafter, as long as the empty sensor S4 detects the presence of a document, the same processing is performed on the documents D4, D5,.
[0093]
Similarly, except for the final document, double-sided scanning productivity can be remarkably improved by simultaneously performing empty reversal for page alignment of a document that has been scanned and scanning the next document at the same time as described above. It was.
[0094]
Note that the drive of the transport motor M2 is stopped after the time required for the last document to be discharged to the discharge tray 16 after the discharge sensor S7 detects the trailing edge of the last document, and the pressure contact solenoid SOL is excited. Is canceled and the processing of all originals is completed.
[0095]
Here, a reading operation when high-precision reading is selected will be described.
[0096]
First, reading of the first double-sided scanned original will be described. When the empty sensor S4 detects that an original is placed on the paper feed tray 15, the first original D1 is fed forward by the feed roller 18 and the paper feed by the forward drive of the paper feed motor M1 as in the single-sided reading mode. The roller 19 is rotated so that the original is brought into contact with the nip point of the registration roller pair 21 to remove the skew.
[0097]
The document D1 conveyed by the reverse rotation drive of the paper feed motor M1 and the forward rotation drive of the carry motor M2 is detected by the lead sensor S6, and then the paper feed motor M1 and the carry motor M2 are temporarily stopped. The document D1 is in a state where the leading end position is stopped before the first platen 2. At this time, the pressure contact solenoid SOL is excited and the paper discharge roller pair 24 is pressed (FIG. 13A).
[0098]
When the reading conveyance signal is received from the image reading apparatus main body 1, the conveyance motor M2 is driven to rotate forward, so that the surface of the document is sent onto the first platen 2 and sub-scanned and read by the reading means. The document D1 read by the first platen 2 is guided to the paper discharge path 27.
[0099]
The document D1 guided from the paper discharge path 27 to the paper discharge port 31 is conveyed onto the paper discharge tray 16 by pushing up the front end of the flapper 29 disposed so as to block the paper discharge port 31 at the front end. In this conveyance state, when the time required for the trailing edge of the document D1 to pass the position of the flapper 29 has elapsed after the paper discharge sensor S7 detects the trailing edge of the document D1, the driving of the conveyance motor M2 is stopped, and the document In D1, the rear end side is nipped by the discharge roller pair 24 and stops (see FIG. 13B).
[0100]
Thereafter, the transport motor M2 is driven in reverse. As a result, the paper discharge roller 24a rotates in the reverse direction, the original D1 is switched back, and the paper is returned from the switchback path 28 along the original guide surface of the flapper 29 that has moved to a position that closes the paper discharge outlet 31 as the original passes. Guided to the paper feed path 30. The conveyance motor M2, which is driven in reverse, removes the skew because the deflection of the registration roller pair 21 is formed after the leading edge of the document D1 guided to the refeed path 30 is detected by the registration sensor S5. Then, it is stopped after a predetermined time (see FIG. 13C).
[0101]
Then, the paper feed motor M1 is driven in reverse to re-feed the original D1. The registration roller 21a is rotated in the sheet feeding direction by the reverse rotation of the sheet feeding motor M1, and after the time that the leading edge of the document D1 securely nips the registration roller pair 21, the excitation of the pressure contact solenoid SOL is released, and the sheet discharge driven roller 24b is moved downward to be separated from the paper discharge roller 24a, and the transport motor M2 is driven forward.
[0102]
When the document D1 is reversed and fed along the paper feed path 25 and the leading edge thereof is detected by the lead sensor S6, the transport motor M2 stops after a predetermined time and also stops the paper feed motor M1. Thereafter, the conveyance motor M2 is re-driven by the reading conveyance signal from the image reading apparatus main body 1, and the back surface of the document D1 is sub-scanned and read by the reading unit. At this time, the leading edge side of the document D1 sent to the sheet discharge tray 16 and the trailing edge side of the document D1 to be fed again pass at a common portion of the sheet discharge path 27 including the sheet discharge roller pair 24 and the switchback path 28. However, since the discharge roller pair 24 is in a separated state, it can be transported without any trouble (see FIG. 13D).
[0103]
Thereafter, when the registration sensor S5 detects the trailing edge of the document D1, the pressure contact solenoid SOL is excited, the discharge roller pair 24 is pressed, and the discharge sensor S7 detects a trailing edge of the document D1 for a predetermined time. When the time has elapsed, the driving of the conveyance motor M2 is stopped, and the document D1 is stopped with its rear end side being nipped by the paper discharge roller pair 24 (see FIG. 13E).
[0104]
Then, the document D1 is reversed 180 degrees and fed to the paper discharge tray 16 so as to be discharged in the same page order. In order to re-feed the original D1, the paper feed motor M1 is driven in reverse. The registration roller 21a is rotated in the sheet feeding direction by the reverse rotation of the sheet feeding motor M1, and after the time that the leading edge of the document D1 securely nips the registration roller pair 21, the excitation of the pressure contact solenoid SOL is released, and the sheet discharge driven roller 24b is moved downward to be separated from the paper discharge roller 24a, and the transport motor M2 is driven forward.
[0105]
The document D1 is reversed along the paper feed path 25 and fed to the paper discharge path 27. At this time, the leading edge side of the document D1 sent to the sheet discharge tray 16 and the trailing edge side of the document D1 to be fed again pass at a common portion of the sheet discharge path 27 including the sheet discharge roller pair 24 and the switchback path 28. However, since the discharge roller pair 24 is in a separated state, it can be transported without any trouble (see FIG. 13D).
[0106]
The document D1 guided from the paper discharge path 27 to the paper discharge port 31 is conveyed onto the paper discharge tray 16 by pushing up the front end of the flapper 29 disposed so as to block the paper discharge port 31 with the front end of the document D1. . In this transport state, when it is detected that the trailing edge of the document D1 has passed the transport roller pair 23, the document D1 is transported at the peripheral speed of the sheet discharge roller 24a (first sheet discharge roller) (FIG. 14). (Refer to (f)).
[0107]
Next, when the registration sensor S5 detects passage of the trailing edge of the document D1, it is checked whether or not the empty sensor S4 detects the presence of the next document. If there is, the second document D2 is detected. The paper feeding operation is started (see FIG. 13G).
[0108]
The trailing edge of the document D1 falls on the paper discharge tray 16 to complete the discharge (see FIG. 13 (h)).
[0109]
In the same way as the first sheet, the second sheet D2 is rotated by the forward rotation of the sheet feeding motor M1 to rotate the feeding roller 18 and the sheet feeding roller 19, and the document is brought into contact with the nip point of the registration roller pair 21 to remove the skew. Then, the document D2 conveyed by the reverse rotation drive of the paper feed motor M1 and the forward rotation drive of the conveyance motor M2 is nipped by the registration roller pair 21 and temporarily stopped (see FIG. 13A).
[0110]
Thereafter, after reading the front and back of the second document D2 by the same operation as the first document D1, the document D2 is reversed 180 degrees and discharged to the discharge tray 16 with the page order aligned. Skip forward.
[0111]
When the registration sensor S5 detects passage of the trailing edge of the document D2, it is checked whether or not the empty sensor S4 detects the presence of the next document, and if there is, the same 3 as the second document D2. The feeding operation of the first document D3 is started. The reading operation of the third document D3 is performed by repeating the operations shown in FIGS. 13 (a) to 15 (h).
[0112]
Thereafter, as long as the empty sensor S4 detects the presence of a document, the same processing is performed on the documents D4, D5,.
[0113]
In this way, in high-precision reading, since the originals are conveyed and read one by one, the original surface facing the original that is generated when two sheets are conveyed in high-speed reading may be read through. Disappear. Therefore, a clear and highly precise image can be obtained.
[0114]
Note that the drive of the transport motor M2 is stopped after the time required for the last document to be discharged to the discharge tray 16 after the discharge sensor S7 detects the trailing edge of the last document, and the pressure contact solenoid SOL is excited. Is canceled and the processing of all originals is completed.
[0115]
FIG. 16 shows a flowchart of the flow of an example of document conveyance processing in high-speed reading. The flow of the duplex reading original conveyance process will be described with reference to FIG.
[0116]
First, an operation of reading the first original is performed. The original placed on the paper feed tray is fed to a predetermined paper feed position (ST1). The document fed to the feeding position is conveyed to the reading position (ST2).
[0117]
One side of the original conveyed to the predetermined reading position is read (ST3). The original on which one side is read is switched back and reversed (ST4). The document which is switched back and reversed is fed again to the feeding position (ST5).
[0118]
The original on which one side is read is conveyed and the other side of the original is read (ST6). The document that has been read on both sides is switched back again and reversed (ST7). The original that has been read on both sides is conveyed again to the paper feed position (ST8).
[0119]
The original for which double-sided reading has been completed is conveyed via the reading position while being overlapped with the next fed original (second original) (ST9). Here, one side of the document fed next is read (ST10).
[0120]
The front end of the original (first original) that has been read on both sides is shifted backward by a predetermined distance from the front end of the next supplied original (second original) at the paper feed position. Transport in state. Next, the document on which one side of the fed document is read is switched back and sent to the feeding position (ST11). The document that has been read on both sides (the first document) is discharged (ST12).
[0121]
Next, the other side of the original (second original) that has been fed and read on one side is read (ST13). If there are further documents to be read, processing steps ST7 to ST11 are repeatedly executed (ST14). If there is no original, the last read original is switched back, reversed, fed forward, and discharged (ST15).
[0122]
Here, another embodiment according to the present invention will be described. 17 and 18 are cross-sectional views showing a second embodiment of the ADF 10.
[0123]
A second embodiment of the ADF 10 will be specifically described with reference to a document conveyance control operation based on FIGS. 17 and 18. Since the reading of the first document is the same as in the first embodiment, description thereof is omitted.
[0124]
In the second embodiment, the document D1 that has been transported to the paper discharge path 27 and has been read is driven in the reverse direction by the transport motor M2 and is transported from the switchback path 28 to the refeed path 30 so that the registration roller pair 21 The leading edge of the document D1 is brought into contact with the nip portion to remove the skew (see FIG. 17A). The leading edge is conveyed from the registration roller pair 21 by a certain distance (distance “Z” shown in FIG. 17B) and temporarily stopped.
[0125]
Next, in the same manner as the first sheet, the second document D2 rotates the feeding roller 18 and the sheet feeding roller 19 by normal rotation driving of the sheet feeding motor M1, and the document is brought into contact with the nip point of the registration roller pair 21. The skew is removed, and the sheet is conveyed in the reading position direction by the reverse rotation driving of the paper feed motor M1 and the forward rotation driving of the conveyance motor M2.
[0126]
In this case, the first document D1 is conveyed prior to the second document D2, and the displacement direction between the first document D1 and the second document D2 is opposite to that in the first embodiment. It has become. (See FIG. 17 (b). Deviation amount: Z).
[0127]
Two sheets of document D2 are simultaneously fed in a state where the document D1 is overlapped by the reverse rotation drive of the sheet feed motor M1 and the forward rotation drive of the transport motor M2, and the drive of the sheet feed motor M1 is stopped by detecting the leading edge of the document D1 of the lead sensor S6 To do. After the leading edge is detected by the lead sensor S6, the paper feed motor M1 and the conveyance motor M2 are temporarily stopped, and the document D1 is in a state where the leading edge is stopped before the first platen 2. At this time, the pressure contact solenoid SOL is excited and the paper discharge roller pair 24 is pressed.
[0128]
The reading start position is pulse-counted for a set deviation amount from the leading edge of the document D1, specifies the reading start position, and starts reading.
[0129]
When a reading conveyance signal is received from the image reading apparatus main body 1, the conveyance motor M2 is driven to rotate forward, whereby the surface of the document D2 is sent onto the first platen 2 and sub-scanned and read by the reading means. (See FIG. 17 (c)).
[0130]
The document D1 that is sent together with the document D2 read by the first platen 2 is guided to the paper discharge path 27. The peripheral speeds of the paper discharge rollers 24a and 24b are the same, and no speed difference is provided.
[0131]
The document D1, which is sent together with the document D2 guided from the paper discharge path 27 to the paper discharge port 31, is pushed up by the front end of the flapper 29 arranged so as to block the paper discharge port 31 with the front end of the document D1. It is conveyed onto the paper tray 16.
[0132]
When the discharge sensor S7 detects the trailing edge of the document D1 and the passage of the trailing edge of the document D1 downstream of the flapper 29 is detected, the driving of the transport motor M2 is stopped. The rear end side of the document D2 is nipped by the paper discharge roller pair 24 and stopped (see FIG. 18D).
[0133]
Thereafter, the transport motor M2 is driven in reverse. As a result, the paper discharge rollers 24a and 24b rotate reversely, the original D1 stops at the reverse return prevention lever 35, only the original D2 is switched back, and the flapper moved to a position that closes the discharge outlet 31 as the original passes. It is guided to the switchback path 28 along the document guide surface 29 (FIG. 18E).
[0134]
The conveyance motor M2, which is driven in reverse, is bent at the nip portion of the registration roller pair 21 after the leading edge of the document D2 guided from the switchback path 28 to the refeed path 30 is detected by the registration sensor S5. The skew is removed and stopped after a predetermined time.
[0135]
Then, the paper feed motor M1 is driven in reverse to re-feed the original D2. The registration roller 21a is rotated in the paper feeding direction by the reverse rotation of the paper feed motor M1, and after the time that the leading edge of the document D2 is securely nipped by the registration roller pair 21, the excitation of the pressure contact solenoid SOL is released, and the paper discharge roller 24b. Is moved downward to move away from the paper discharge roller 24a, and the transport motor M2 is rotated forward. When the trailing edge of the document D2 passes the reverse prevention lever 35, the trailing edge of the document D1 that has been stopped by the reverse prevention lever 35 falls to the paper discharge tray 16 to complete the discharge (see FIG. 18 (f)).
[0136]
The document D2 is conveyed to the conveyance path 26, and the back surface of the document D2 is read by the same operation as the reading of the front surface.
[0137]
In the second embodiment, since the trailing edge of the document D1 precedes the trailing edge of the document D2, the document D1 can be discharged without providing a speed difference between the discharge rollers 24a and 24b.
[0138]
19 and 20 are cross-sectional views showing a third embodiment of the ADF 10.
[0139]
A third embodiment of the ADF 10 will be specifically described with reference to FIG. 19 and FIG. Since the reading of the first document is the same as in the first embodiment, description thereof is omitted.
[0140]
In the third embodiment, the registration rollers 21a and 21b, the transport rollers 22a and 22b, the transport rollers 23a and 23b, and the paper discharge rollers 24a and 24b are all provided with a speed difference. The speed differences are the registration rollers 21a> 21b, the conveyance rollers 22a> 22b, and the conveyance rollers 23a> 23b, and a torque limiter is built in each of the registration rollers 21a, the conveyance rollers 23a, and the conveyance rollers 22a.
[0141]
In the third embodiment, the second original D2 is rotated at the nip point of the registration roller pair 21 by rotating the feeding roller 18 and the paper feeding roller 19 by the normal rotation driving of the paper feeding motor M1 as in the first sheet. The document D2 is transported by abutting the document to remove the skew and conveyed by the reverse rotation drive of the paper feed motor M1 and the forward rotation drive of the conveyance motor M2, and the leading edge of the document D2 is conveyed from the registration roller pair 21 by a certain distance (FIG. 19A). The distance of “Z” shown in FIG.
[0142]
The document D1 is reversely driven by the transport motor M2 and transported from the switchback path 28 to the refeed path 30, and the skew of the document D1 is abutted against the nip portion of the registration roller pair 21 (see FIG. 19A). )reference). Note that when only a read document is conveyed (when one sheet is conveyed), the discharge roller 24b is driven by the speed of the discharge roller 24a by a torque limiter.
[0143]
Two sheets of document D2 are simultaneously fed in a state of being overlapped with document D1 by reverse rotation driving of sheet feeding motor M1 and forward rotation of conveying motor M2, and driving of sheet feeding motor M1 is stopped by detecting the leading edge of document D2 of lead sensor S6. . After the leading edge is detected by the lead sensor S6, the paper feeding motor M1 and the conveying motor M2 are temporarily stopped, and the document D2 is in a state where the leading edge is stopped before the first platen 2. At this time, the pressure contact solenoid SOL is excited and the paper discharge roller pair 24 is pressed.
[0144]
Since the speed of each roller pair is registration rollers 21a> 21b and conveying rollers 22a> 22b, the leading ends of the originals D1, D2 are aligned when the originals D1, D2 are conveyed to the reading position (FIG. 19B). reference).
[0145]
When a reading conveyance signal is received from the image reading apparatus main body 1, the conveyance motor M2 is driven to rotate forward, whereby the surface of the document D2 is sent onto the first platen 2 and sub-scanned and read by the reading means. .
[0146]
The document D1 that is sent together with the document D2 read by the first platen 2 is guided to the paper discharge path 27. (See FIG. 19 (c))
The leading edge of the document D1 fed along with the document D2 guided to the sheet discharge path 27 precedes the document D2 at this time, and is a flapper 29 disposed so as to block the sheet discharge port 31 with the tip of the document D1. Is pushed up and conveyed onto the paper discharge tray 16.
[0147]
When the paper discharge sensor S7 detects the trailing edge of the document D1 and detects that the trailing edge of the document D1 passes through the position of the reverse return prevention lever 35 provided downstream of the flapper 29, the driving of the transport motor M2 is stopped and the document D2 is stopped. The rear end side is nipped by the paper discharge roller pair 24 and stops (see FIG. 20D).
[0148]
Thereafter, the transport motor M2 is driven in reverse. As a result, the paper discharge rollers 24a and 24b rotate reversely, the original D1 stops at the reverse return prevention lever 35, only the original D2 is switched back, and the flapper moved to a position that closes the discharge outlet 31 as the original passes. It is guided to the switchback path 28 along the document guide surface 29 (FIG. 20E).
[0149]
The conveyance motor M2, which is driven in reverse, is bent at the nip portion of the registration roller pair 21 after the leading edge of the document D2 guided from the switchback path 28 to the refeed path 30 is detected by the registration sensor S5. The skew is removed and stopped after a predetermined time.
[0150]
Then, the paper feed motor M1 is driven in reverse to re-feed the original D2. The registration roller 21a is rotated in the paper feeding direction by the reverse rotation of the paper feed motor M1, and after the time that the leading edge of the document D2 is securely nipped by the registration roller pair 21, the excitation of the pressure contact solenoid SOL is released, and the paper discharge roller 24b. Is moved downward to move away from the paper discharge roller 24a, and the transport motor M2 is rotated forward. When the trailing edge of the document D2 passes the reverse prevention lever 35, the trailing edge of the document D1 that has been stopped by the reverse prevention lever 35 falls to the paper discharge tray 16 and the discharge is completed (see FIG. 20F).
[0151]
The document D <b> 2 is conveyed onto the first platen, the back side is read, and conveyed to the paper discharge path 27.
[0152]
As described above, in the third embodiment, the document D2 can be preceded by a long distance from the position where the leading edge of the document D2 passes the lead sensor S6 to the switchback point (from the document D1 resist to the read sensor). The amount of the document D1 is set so that the trailing edge of the document D1 can precede the trailing edge of the document D2.
[0153]
As described above in detail, the document feeder of the present invention feeds a document feed tray on which a document is placed and a document placed on the feed tray one by one to a predetermined feed position. A paper feed unit for feeding paper, a transport unit for transporting the fed document from the paper feed position to the paper discharge port via the reading position, and a document back-feeding direction. A switchback path for reversing the sheet, a refeed path for guiding the document that has been switched back and reversed in the switchback path to the sheet feeding position, and a downstream end of the switchback path. A paper discharge means for discharging the original after reading onto the paper discharge tray, and the original after the double-sided reading is sent to the paper feed position via the switchback path, By The document to be read next after being fed and the document that has been scanned on both sides are read at the reading position. It is conveyed in a stacked state, Conveyance for reading the document to be read next and conveyance for discharging the document after the double-sided reading to the paper discharge tray are performed simultaneously. It is characterized by that.
[0154]
In the document conveying apparatus and the document conveying method of the present invention, the feeding and reading for reading the next document can be performed by superimposing and feeding the blank document that has been read for page alignment and the next scanned document. It is now possible to simultaneously feed the finished manuscript. As a result, it is possible to perform a double-sided scanning operation in which the page order of the read original is aligned as it is without being reversed.
[0155]
Furthermore, in order to read a double-sided document, it is necessary to transport the document to the front side scanning, back side scanning, idle feed, and triple reading position. The reading operation can be speeded up.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an ADF mounted on an image reading apparatus according to the present invention.
FIG. 2 shows an enlarged cross-sectional view of the ADF shown in FIG.
3 shows a drive diagram (part 1) of the ADF shown in FIG. 1. FIG.
4 shows a drive diagram (part 2) of the ADF shown in FIG. 1. FIG.
FIG. 5 is an enlarged view of a transported document detection unit according to the ADF shown in FIG. 1;
6 is a diagram (No. 1) schematically showing a document transport state in the single-sided reading mode of the ADF shown in FIG. 1. FIG.
FIG. 7 is a diagram (part 2) schematically illustrating a document conveyance state in the single-sided reading mode of the ADF illustrated in FIG.
FIG. 8 is a diagram (No. 1) schematically showing a document transport state in a duplex scanning mode with ADF high-speed scanning in the first embodiment.
FIG. 9 is a diagram (part 2) schematically illustrating a document transport state in the duplex scanning mode by high-speed scanning of ADF in the first embodiment.
FIG. 10 is a diagram (part 3) schematically illustrating a document conveyance state in the duplex scanning mode in high-speed scanning of ADF in the first embodiment.
FIG. 11 is a diagram (part 4) schematically illustrating a document transport state in the duplex scanning mode by high-speed scanning of the ADF in the first embodiment.
FIG. 12 is a diagram (No. 5) schematically showing a document transport state in the duplex scanning mode with high-speed scanning of ADF in the first embodiment.
FIG. 13 is a diagram (part 1) schematically illustrating a document conveyance state in a double-sided scanning mode of ADF in high-precision scanning.
FIG. 14 is a diagram (part 2) schematically illustrating a document conveyance state in a double-sided scanning mode of ADF in high-precision scanning.
FIG. 15 is a diagram (part 3) schematically illustrating a document conveyance state in a double-sided reading mode of ADF in high-precision reading.
FIG. 16 shows a flowchart of a flow of an example of document conveyance processing according to the present invention.
FIG. 17 is a diagram (part 1) schematically illustrating a document conveyance state in the ADF duplex reading mode according to the second embodiment.
FIG. 18 is a diagram (part 2) schematically illustrating a document conveyance state in the double-sided reading mode of the ADF in the second embodiment.
FIG. 19 is a diagram (part 1) schematically illustrating a document conveyance state in the ADF duplex reading mode according to the third embodiment.
FIG. 20 is a diagram (part 2) schematically illustrating a document conveyance state in the double-sided reading mode of the ADF in the third embodiment.
[Explanation of symbols]
2 First platen
10 Automatic document feeder (ADF)
10b Exterior cover
11 Paper feed unit
12 Transport section
13 Paper output section
14 Switchback section
15 Paper tray
16 Output tray
25 Paper feed path
25a Paper feed guide
25b Feeding lower guide
25c protrusion
35 Reverse prevention lever
S6 Lead sensor
S6a Sensor lever
S6c Sensor flag
S6d Sensor body

Claims (12)

A paper feed tray on which documents are placed;
A paper feed means for feeding out the originals placed on the paper feed tray one by one and feeding them to a predetermined paper feed position;
Transport means for transporting a fed document from the paper feed position to the paper discharge port via the reading position;
A switchback path provided in the paper discharge direction of the paper discharge port, for switching back and reversing the document;
A refeeding path that guides the document that has been switched back and reversed in the switchback path to the feeding position;
A discharge means provided at the downstream end of the switchback path for discharging the document after image reading onto a discharge tray;
A document that has been read on both sides is sent to the paper feed position via the switchback path, and a document that is read next after being fed by the paper feed unit and a document that has been scanned on both sides are read in the reading position. And the conveyance for reading the next document to be read next and the conveyance for discharging the document after the double-sided reading to the discharge tray are performed simultaneously. Document transport device.   2. The document having been read on both sides is conveyed while being overlapped in a state where the leading edge of the document is shifted by a predetermined distance from the leading edge of the document to be read next at the paper feeding position. Document transport apparatus described in 1.   2. The discharge unit according to claim 1, wherein the discharge unit includes a pair of discharge rollers that are rotatable at different rotational speeds in order to discharge the document on which the double-sided reading has been completed to the discharge tray. Document transport device.   The pair of paper discharge rollers is composed of a first paper discharge roller that contacts the original that has been read on both sides of the stacked originals and a second paper discharge roller that contacts the original to be read next, and 4. The document conveyance according to claim 3, wherein when the document on which double-sided scanning is completed is discharged onto the discharge tray, the first discharge roller is rotated at a higher speed than the second roller. apparatus.   The paper discharge roller pair switches back the original to be read next by reversing the rotation direction after detecting that the original on which the double-sided scanning has been completed has passed through the paper discharge roller pair, thereby supplying the paper. The document feeder according to claim 3, wherein the document feeder is fed to a paper position.   The paper discharge roller pair includes a reverse prevention lever that stops a rear end of the original so that the original that has been read does not switch back when the rotation direction of the paper discharge roller pair is reversed. The document conveying device according to claim 1. Feeding a document placed on a paper feed tray to a predetermined paper feed position;
A step of conveying the original, which is the sheet of paper,
Reading one side of the document conveyed to a predetermined reading position;
Switching back and reversing the document on which the one side is read;
Feeding the document that has been switched back and reversed to the feeding position again;
Conveying the document on which the one side is read and reading the other side of the document;
A step of switching back and reversing the original that has been read on both sides;
Re-sending the original on which the duplex reading has been completed to the paper feed position;
Transporting the document that has been read on both sides via the reading position in a state of being overlaid on the next fed document;
Discharging the original after the double-sided scanning;
Each step of
In the step of transporting the document that has been read on both sides via the reading position while being overlapped with the next fed document, one side of the next fed document is read. An original reading method. In the step of transporting the document that has been read on both sides via the reading position in a state of being overlapped with the next fed document,
8. The document that has been read on both sides is conveyed in a state in which the leading edge of the document is shifted backward by a predetermined distance from the leading edge of the next fed document at the feeding position. Document transport method.   The method includes a step of switching back a document on which one side of the next fed document is read and sending the document to the feeding position after the step of discharging the document that has been read on both sides. The document conveying method according to claim 7.   The document conveying method according to claim 9, further comprising a step of reading the other side of the document that is fed next and whose one side is read. Conveying means for feeding out the documents one by one and conveying them to a predetermined reading position;
Reading means for reading a document image that moves in the reading position;
A switchback path that replaces the front and back of the document read at the reading position, and reverses the front and back to refeed the reading position;
A paper discharge means for discharging the read original,
Reads the front and back surfaces of the document by the reading means and transported twice document from the reading position to the switch back path, wherein by superimposing the fed document original and next the two sides of the reading has been completed An image reading apparatus comprising: a control unit configured to read the next fed document conveyed to a reading position and superimposed and conveyed by the reading unit. The control unit conveys the document twice from the reading position to the switchback path, reads the front and back of the document by the reading unit, and then superimposes the document that has been read and the next fed document. A control for reading the next fed document fed in an overlapping manner and transported to the reading position by the reading means;
The original is transported twice from the reading position to the switchback path, the front and back sides of the original are read by the reading means, and the original that has been read is turned over and discharged by the paper discharging means, and then fed. The image reading apparatus according to claim 11, wherein the image reading apparatus can be selected and controlled.

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