JP2006213457A - Sheet conveying device and image reader provided with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive sheet conveying device capable of shortening a time required for conveying all sheets, and an image reader provided with the same. <P>SOLUTION: The sheet conveyed from a sheet placement means 102 by a sheet conveying means 203 is conveyed to a reader part 202 via a sheet conveying passage 208 and the sheet with the image already read by an image reading part 202 is inversed and conveyed again to the sheet conveying passage 208 via a re-conveying passage 206 branched from a paper delivery passage 220. Further, after the images of both first surface and second surface are read, the subsequent sheet conveyed by the sheet conveying means 203 is superposed on the preceding sheet inversed and conveyed to the sheet conveying passage 208 and is conveyed, the preceding sheet is delivered to a paper delivery part 108 and the subsequent sheet is directed from the re-conveying passage 206 to the image reading part 202. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a sheet conveying apparatus and an image reading apparatus including the sheet conveying apparatus, and in particular, conveys a sheet having images formed on both sides to an image reading unit to read the images on both sides, and then reverses and discharges the sheet. It relates to what I did.

  2. Description of the Related Art Conventionally, image reading apparatuses such as facsimiles and scanners read document images by a so-called flow reading method, for example, while reading a document as a sheet. In this case, an automatic document feeder (ADF) as an example of a sheet conveying device conveys a document placed on a document stacking tray to an image reading unit (a reading position), and then discharges the document on which an image has been read. It is discharged to the paper tray.

  Here, as such an automatic document feeder, for example, when reading an image of a document having images formed on both sides, the document having images formed on both sides is first transported to a reading position. After the image on one side is read, a part of the original after the image is read is once transported to the paper discharge tray, and then switched back without completely discharging the original to the paper output tray. The document is again fed to the document feeding path via the feeding path.

  Next, the reversed document is conveyed to the reading position through the duplex feeding path and the document feeding path to read the image on the second side, and then fed to the paper discharge tray. In order to keep the page order even if the originals are stacked on the paper discharge tray, the original is then switched back without being completely discharged onto the paper output tray, and then the original feed path via the duplex feeding path. The document is discharged to the paper discharge tray with the first side down, and is stacked (see, for example, Patent Document 1).

  In addition, as an automatic document feeder having another configuration, a reading unit that reads the back side of a document is provided. When reading a document on which images are formed on both the front and back sides, the document is read by a reading unit provided in the image reading device. When transporting, the back side of the document is read by the reading means on the apparatus side, so that the document information on both the front and back sides of the document is read at the same time, and then discharged and stacked on the discharge tray (for example, Patent Document 2). reference.).

JP-A-10-218466 Japanese Patent Laid-Open No. 10-081449

  However, in such a conventional automatic document feeder and an image reading apparatus including the same, the apparatus described in Patent Document 1 is ready to read the next document after the document reading is completed. In order to eject the originals in order, it is necessary to pass the original through the original reading section even though the original is not read. Therefore, the next original can be fed even after the reading is completed. Therefore, it takes a long time to convey all the documents, leading to a decrease in productivity.

  Further, the device described in Patent Document 2 includes a reading unit for reading the back side of the document, so that the configuration becomes complicated and expensive.

  Therefore, the present invention has been made in view of such a current situation, and is an inexpensive automatic document feeder (sheet conveying device) that can reduce the time required to convey all originals (sheets), and An object of the present invention is to provide an image reading apparatus provided with this.

  In the present invention, a sheet on which images are formed on both sides is conveyed to an image reading unit, a sheet on which an image on the first side is read is reversed and conveyed again to the image reading unit, and then an image on the second side. In the sheet conveying apparatus in which the read sheet is reversed again and discharged to the sheet discharge unit, the sheet conveying unit conveys the sheet one by one from the sheet placing unit, and the sheet conveying unit conveys the sheet one by one A sheet conveyance path for conveying a sheet to the image reading unit, a sheet discharge path for conveying a sheet whose image has been read by the image reading unit to the sheet discharge unit, and a branch from the sheet discharge path, A re-conveying passage for inverting the sheet after the image has been read and conveying the sheet again to the sheet conveying passage, and after the images on both sides of the first surface and the second surface are read The sea The next sheet conveyed by the sheet conveying means is superimposed and conveyed on the preceding sheet conveyed by being reversed to the conveying path, and the preceding sheet conveyed while being superimposed is discharged to the paper discharge unit, The next sheet is directed from the re-conveyance path to the image reading unit.

  Further, the present invention is provided in a joining portion of the sheet conveyance path and the re-conveyance path, stops in a state where the preceding sheet is held until the next sheet arrives, and after the next sheet arrives, The image forming apparatus includes an overlapping conveyance unit that overlaps and conveys the preceding sheet and the next sheet.

  In the present invention, the next sheet is provided in the sheet discharge path and discharged in a reverse direction after discharging the preceding sheet conveyed to the sheet discharge unit and then reversely rotating the sheet. It is characterized by having a discharging means that can be rotated forward and backward.

  According to the present invention, an image reading apparatus includes an image reading unit and any one of the sheet conveying devices described above that conveys a sheet to the image reading unit.

  The present invention is also characterized in that the image reading apparatus main body or the sheet conveying apparatus is provided with control means for controlling the image reading operation of the image reading unit.

  In the invention, it is preferable that the control unit controls the image reading unit so as to read an image of the next sheet conveyed in a state of being superimposed by the overlapping conveyance unit.

  According to the present invention, the control means controls the image reading unit so that the image reading operation is not performed on the next sheet when the next sheet is conveyed in the overlapped state. It is characterized by.

  According to the present invention, the next sheet is overlapped and conveyed on the preceding sheet from which the images on both sides have been read, and the preceding sheet is discharged to the sheet discharge unit, and the next sheet is transferred from the re-conveyance path to the image reading unit. By making them face each other, it is inexpensive and the time required for transporting all the sheets can be shortened. And productivity can be improved by shortening the time required for conveyance of all the sheets in this way.

  The best mode for carrying out the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of an image reading apparatus provided with an automatic document feeder as an example of a sheet conveying apparatus according to an embodiment of the present invention, and FIG. 2 is a perspective view thereof. The image reading apparatus can be installed in the main body of an image forming apparatus such as a copying machine or a facsimile.

  In FIGS. 1 and 2, reference numeral 201 denotes an image reading apparatus, and reference numeral 101 denotes an automatic document feeder (ADF) provided on the upper part of the image reading apparatus 201.

  Here, the image reading apparatus 201 includes a reader unit 202 as an example of an image reading unit having an image reading sensor (not shown), and a document sent by the automatic document feeder 101 is placed at the image reading position 231. When it reaches, the reader unit 202 reads the image on the document. Note that the image information read by the reader unit 202 is processed by an image processing unit (not shown), and then, for example, when the image reading device 201 is installed in the image forming device (not shown), the image forming apparatus The image forming unit forms an image on a recording medium based on the processed image information.

  In FIGS. 1 and 2, reference numeral 102 denotes a document stacking tray as an example of a sheet placing unit for placing a document bundle, and 110 detects a document set on the document stacking tray 102 and a final document. This is a document set sensor. Reference numerals 103 to 105 denote first to third tray sensors provided on the document stacking tray 102. By the first to third tray sensors 103 to 105, the sub-scanning direction (conveyance) of the documents stacked on the document stacking tray 102 is performed. (Approx. Direction) can be detected.

  Reference numeral 106 denotes a side restricting plate provided on the document stacking tray 102. The side restricting plate 106 is connected to a width detecting sensor 414 shown in FIG. The document length (document width) in the main scanning direction (width direction orthogonal to the transport direction) can be detected. The width detection sensor 414 and the first to third tray sensors 103 to 105 can determine the document size.

  204 is a separation roller, and 203 is a pickup roller as an example of a sheet conveying unit. When a separation motor 404 shown in FIG. 8 (described later) is rotated forward during document feeding, the separation roller 204 rotates in the paper feeding direction. In conjunction with the separation roller 204, the pickup roller 203 is lowered while rotating in the paper feeding direction to convey the uppermost sheet of the document.

  The uppermost sheet of the document conveyed by the pickup roller 203 is conveyed by the separation roller 204, but the subsequent sheet is stopped by the deterring force of a separation pad (not shown) pressed against the separation roller 204. Thus, it is possible to prevent double feeding.

  Reference numeral 205 denotes a registration sensor that detects a document conveyed by the separation roller 204. Reference numeral 207 denotes a registration roller. The conveyed document is once applied to the registration roller 207 to form a predetermined loop, and is skewed by stopping. Is done. Then, after the skew correction of the document is performed, a sheet feeding motor 416 shown in FIG. 8 to be described later is rotated, whereby the registration rollers 207 are rotated in the transport direction, and the transport of the document is resumed.

  When the conveyance of the original by the registration roller 207 is resumed (or until then), the separation motor 404 is stopped, whereby the pickup roller 203 stops rotating. Further, after that, the pickup roller 203 is moved to the retracted position by rotating the separation motor 404 in the direction opposite to the conveying direction.

  Here, when the rotation of the separation motor 404 is stopped, the separation roller 204 cannot be driven to rotate. However, the separation roller 204 can be rotated in the transport direction by a one-way mechanism (not shown). When the registration roller 207 is rotated by the rotation of the motor 416, the separation roller 204 is rotated along with the original so that the original conveyance is not hindered.

  A lead sensor 211 is provided in the transport path (sheet transport path) 208 and detects the leading edge of the document transported by the registration roller 207. After the leading sensor 211 detects the leading edge of the document, the document is scanned at the document reading position. The document transport is temporarily stopped before reaching 231.

  Reference numerals 209 and 210 denote lead rollers that are rotated by a read motor 406 shown in FIG. 8 to be described later. is there. Then, by rotating the paper feed motor 416 and the read motor 406, the registration roller 207, the lead rollers 209 and 210, and the discharge roller pair 212 (212a and 212b) are rotated. At this time, the image is read by the image reading device 201 (the reader unit 202 thereof), and then discharged through the paper discharge passage 220.

  Note that one discharge roller 212a constituting the discharge roller pair 212 is normally located at a position separated from the other discharge roller 212b, and after the document trailing edge has passed the reading position, the other discharge roller 212a is separated by a separation solenoid (not shown). The sheet is moved to a position where it is in pressure contact with the discharge roller 212b, so that the document can be conveyed by the discharge roller pair 212.

  Reference numeral 213 denotes a path switching flapper, and the path switching flapper 213 is pressed downward by a spring (not shown). When a document is conveyed through the paper discharge passage 220, the path switching flapper 213 is switched upward by a switching solenoid (not shown). A paper discharge sensor 215 detects the trailing edge of the document. After detecting the passage of the trailing edge of the document by the paper discharge sensor 215, the document trailing edge passes the position of the path switching flapper 213 by transporting a predetermined distance. Then, when the document is reversed and moved again toward the conveyance path 208, the document conveyance is stopped, the path switching flapper 213 is switched to the lower side, and the discharge roller pair 212 is further reversed to reverse the document. It conveys in the reverse direction.

  The original conveyed in the reverse direction as described above is conveyed to a registration roller 207 provided at a branch point between the re-conveyance path 206 and the conveyance path 208 via the re-conveyance path 206. When the document is transferred to the registration roller 207, the discharge roller pair 212 is separated and thereafter conveyed by the registration roller 207.

  Reference numeral 108 denotes a paper discharge tray as an example of a paper discharge unit for stacking originals to be discharged after reading is completed. Reference numeral 107 denotes an external cover. If a paper jam or the like occurs, the external cover 107 is provided. Is opened counterclockwise to remove jammed originals.

  Next, the flow of a document when reading an image of a double-sided document in the automatic document feeder 101 configured as described above will be described with reference to FIGS.

  First, it is confirmed that the DF cover 107 is closed by a DF cover open sensor (not shown), and whether or not the document G is set on the document stacking tray 102 is detected by the document set sensor 110. When the original G is set as shown in a) and is detected by the original setting sensor 110, a “READY signal” indicating that the automatic original feeder 101 is capable of feeding the image reading apparatus 201. ".

  Next, it waits for the reception of a “document feeding signal” indicating the start of the feeding operation of the document G from the image reading apparatus 201. When the “document feeding signal” is received, the separation motor 404 (see FIG. 8) is rotated. The rotation of the separation roller 204 in the paper feeding direction is started, and the pickup roller 203 is rotated in the paper feeding direction, and is moved from the retracted position to the upper pressure contact position of the original bundle as shown in FIG. G separation / conveyance operation is started.

  Next, after the start of such a separating and conveying operation, it waits for the registration sensor 205 to be turned ON (document leading edge detection), and as shown in FIG. 3C, the registration sensor 205 detects the document G and is turned ON. Then, the separation motor 404 is stopped after a predetermined amount of conveyance, and the rotation of the separation roller 204 is stopped.

  Note that the predetermined transport amount after the document detection is larger than the distance from “document detection position of registration sensor 205 to position of registration roller 207”. Can be taken.

  Next, by rotating the separation motor 404 in the reverse direction, the pickup roller 203 is raised from the pressure contact position on the original bundle to the standby position, and then the paper feed motor 416 (see FIG. 8) is rotated forward to feed the registration roller 207. Rotate in the direction. Although the separation roller 204 loses driving force for conveying the original G by reversing the separation motor 404, the one-way mechanism (not shown) does not hinder the original conveyance by the registration roller 207. Yes.

  Next, it waits for the lead sensor 211 to turn on (document leading edge detection), and when the lead sensor 211 detects the leading edge of the document G and turns on as shown in FIG. After conveying only a fixed amount, the paper feed motor 416 and the read motor 406 are stopped, and the rotation of the registration roller 207 and the read roller 209 is stopped. As a result, the document G is temporarily stopped before the image reading position 231 (first-out position). Further, after the document G is temporarily stopped before the image reading position 231 as described above, a “paper feed completion signal” is transmitted to the image reading apparatus 201.

  Next, the automatic document feeder 101 waits for reception of a “document transport signal” to be transmitted when the image reading device 201 that has received the “paper feed completion signal” becomes ready to read an image. When the “conveying signal” is received, the read motor 406 (see FIG. 8) and the paper feed motor 416 are rotated, the registration roller 207, the read rollers 209 and 210, and the discharge roller pair 212 are rotated, and the leading edge of the original G is read. When the position 231 is reached, an “image reading start signal” that prompts the image reading apparatus 201 to start reading an image of the original G is transmitted. Note that the image reading apparatus 201 reads an image on the first surface of the document G in response to the “image reading start signal”.

  Next, the paper discharge sensor 215 detects the leading edge of the document, the path switching flapper 213 switches to the upper side, and waits for the registration sensor 205 to detect the trailing edge of the document as shown in FIG. When the sensor 205 detects the trailing edge of the document, the document set sensor 110 determines whether the document is the final document. Here, when the document set sensor 110 detects “document exists”, it transmits a “non-final document signal” to the image reading apparatus 201, and when it detects “no document”, it transmits “final document signal”. Send. At the same time, the paper feed motor 416 is stopped and the registration roller 207 is stopped.

  Next, it waits for the lead sensor 211 to detect the trailing edge of the document G, and after the lead sensor 211 detects the trailing edge of the document G, the document G is conveyed by a predetermined amount, and the document trailing edge is moved to the image reading position 231. When it reaches, an “image reading end signal” is transmitted to urge the end of image reading.

  Next, it waits for the paper discharge sensor 215 to detect the trailing edge of the document. When the paper discharge sensor 215 detects the trailing edge of the document, it then transports a predetermined amount to the document reversing position and stops the read motor 406. The original G is temporarily stopped in a state where a part of the original G is discharged to the discharge tray 108. This document reversing position is a position where the trailing edge of the document has passed the switching position of the path switching flapper 213 as shown in FIG.

  Then, after the document G is temporarily stopped in this way, the path switching flapper 213 is switched to the lower side, the read motor 406 is reversed, and the discharge roller pair 212 provided in the sheet discharge passage 220 is reversed. The original G is fed backward. As a result, the document G is conveyed along the upper surface of the path switching flapper 213 to the registration roller side through the re-conveyance path 206 as shown in FIG.

  Next, the registration sensor 205 detects the leading edge of the document G, and stops the read motor 406 after a predetermined amount of conveyance from the leading edge detection of the document G. Note that the conveyance amount after the document detection is larger than “document detection position of registration sensor 205 to registration roller position”, so that a loop can be formed at the leading edge of the document to perform skew feeding.

  Next, the paper feed motor 416 is rotated in the forward direction and the read motor 406 is rotated in the reverse direction, so that the original G is conveyed again. Then, after conveying a predetermined amount, the read motor 406 is stopped and then driven in the forward direction. The predetermined amount at this time is a distance that allows the registration roller 207 to securely nip the leading edge of the original G and convey it.

  Next, as shown in FIG. 4D, the process waits until the lead sensor 211 detects the leading edge of the document G, and after the lead sensor 211 transports the document G by a predetermined amount from the detection, the read motor 406 and the paper feed motor 416 are detected. Is stopped (first-out position), and a “paper supply completion signal” indicating completion of paper supply of the document is transmitted to the image reading apparatus 201.

  When the image reading apparatus 201 receives the “paper feed completion signal” and can read the image, the image reading apparatus 201 transmits a “document transport signal” to the automatic document feeder 101 and receives the “document transport signal”. The automatic document feeder 101 rotates the read motor 406 and the paper feed motor 416 in the normal direction, and re-transports the document G. When the leading edge of the original G reaches the image reading position 231, an “image reading start signal” is transmitted to the image reading apparatus 201 to prompt the image reading start. Note that the image reading apparatus 201 reads an image on the second side of the document G in response to the “image reading start signal”.

  Next, the paper discharge sensor 215 detects the leading edge of the document G from which the image on the second surface has been read, the path switching flapper 213 switches to the upper side, and waits for the registration sensor 205 to detect the trailing edge of the document. When the sensor 205 detects the trailing edge of the document, the paper feed motor 416 is stopped. After that, it waits for the lead sensor 211 to detect the trailing edge of the document G, and after the lead sensor 211 detects the trailing edge of the document G, it conveys a predetermined amount. When the document trailing edge reaches the image reading position 231, the image is read. An “image reading end signal” that prompts the end of reading is transmitted.

  When the image reading on both the front and back sides of the document G is completed as described above, the document G is reversed in order to adjust the page order on the discharge tray.

  In this case, it waits for the paper discharge sensor 215 to detect the trailing edge of the document, and if detected, a predetermined amount to the document reversing position is conveyed, the read motor 406 is stopped, and the document is temporarily stopped. Note that this document reversing position is a position where the trailing edge of the document has passed the switching position of the path switching flapper 213 as shown in FIG. Then, after the document G is temporarily stopped in this way, the path switching flapper 213 is switched to the lower side and the read motor 406 is reversely rotated to reversely feed the document G. As a result, the document G is conveyed along the upper surface of the path switching flapper 213 to the registration roller side through the re-conveyance path 206 as shown in FIG. At this time, the paper feed motor 416 is also rotated forward.

  Next, the registration sensor 205 detects the leading edge of the document G, and then the lead motor 406 and the paper feeding motor 416 are stopped after a predetermined amount of conveyance from the leading edge detection of the document G. Note that the predetermined amount at this time is larger than “pass switching flapper position to discharge roller pair position”, and by conveying such a predetermined amount of the original G, the leading edge of the original G is shown in FIG. As shown in FIG. 4, the vehicle stops (standby) at a position downstream of the registration rollers 207.

  Next, when the original set sensor 110 determines whether or not it is the final original, and the original set sensor 110 detects “there is an original”, and the “non-final original signal” is transmitted, the separation motor 404 is corrected. The separation operation for the next original G1 is started. Then, after the separation operation is started, the document G1 is conveyed until the leading edge of the document G1 hits the registration roller 207, and then the separation motor 404 is stopped after the predetermined amount is conveyed.

  Here, the predetermined amount of conveyance after the leading edge of the document G1 abuts against the registration roller 207 is a loop forming amount by which a loop can be formed at the leading edge of the document, thereby performing skew feeding. At this time, since the preceding document G is conveyed by an amount larger than “path switching flapper position to discharge roller pair position”, as shown in FIG. The leading edge precedes the next original G1.

  Next, the read motor 406 is rotated forward and the paper feed motor 416 is rotated forward, and the registration roller 207 as an example of the superposition transport unit is rotated in the paper feed direction. As a result, the newly separated next document G1 and the preceding document G that has already been scanned on both sides are conveyed in a partially overlapped state, and then the preceding document G is read by the read sensor 211. The tip of is detected. Then, after the predetermined amount is conveyed, the read motor 406 and the paper feed motor 416 are stopped, whereby the originals G and G1 are temporarily stopped at the first position, and the feeding of the originals G and G1 to the image reading apparatus 201 is completed. A “paper feed completion signal” is transmitted.

  Next, the automatic document feeder 101 waits for reception of a “document conveyance signal” to be transmitted when the image reading device 201 becomes ready to read an image. 406 and the paper feed motor 416 are rotated to resume conveyance of the originals G and G1.

  Then, as shown in FIG. 6B, when the leading edge of the next original G1 has been conveyed by a predetermined amount to reach the image reading position 231, an “image reading start signal” that prompts the image reading device 201 to start image reading. Send. Note that the predetermined amount at this time is “first-out position−image reading position + superposition phase distance”. The image reading apparatus 201 reads an image in response to the “image reading start signal”.

  Next, the paper discharge sensor 215 detects the leading edge of the preceding document G, the path switching flapper 213 switches to the upper side, and waits for the registration sensor 205 to detect the trailing edge of the next document G1. As shown in c), when the registration sensor 205 detects the trailing edge of the next original G1, the original set sensor 110 determines whether or not it is the final original. Here, when the document set sensor 110 is “document present”, a “non-final document signal” is transmitted to the image reading apparatus 201, and when “document not present” is transmitted, a “final document signal” is transmitted. At the same time, the paper feed motor 416 is stopped.

  Next, it waits for the lead sensor 211 to detect the trailing edge of the next original G1, and after the lead sensor 211 detects the trailing edge of the next original G1, it conveys a predetermined amount. When 231 is reached, an “image reading end signal” is transmitted to urge the end of image reading.

  Next, it waits for the paper discharge sensor 215 to detect the trailing edge of the next document G1, and when the paper discharge sensor 215 detects the trailing edge of the next document G1, the document is reversed as shown in FIG. A predetermined amount up to the position is conveyed, the read motor 406 is stopped, and the originals G and G1 are temporarily stopped. At this time, the document G is ahead of the document G1 by a predetermined amount (an amount larger than “pass switching flapper position to discharge roller pair position”), so that the trailing edge of the document G passes through the discharge roller pair 212. Then, after the documents G and G1 are temporarily stopped in this way, the path switching flapper 213 is switched to the lower side, the read motor 406 is reversed, and the discharge roller pair 212 is reversed to reversely feed the documents G and G1. Let

  Here, when the originals G and G1 are fed back in this way, the next original G1 is conveyed to the registration roller side along the upper surface of the path switching flapper 213 as shown in FIG. The first original G can be prevented from being fed by the conveyance of the original G1 by a backflow prevention member (not shown) provided downstream in the discharge direction of the discharge roller pair 212 as an example of the discharge unit. It is loaded on the tray. That is, when the two originals G and G1 are conveyed to the discharge tray side by the discharge roller pair 212 and then the discharge roller pair 212 is reversed, the preceding original G that has been discharged first remains as it is. Only the next original G1 is stacked and conveyed to the registration roller side. Thereafter, such an operation is performed until the reading of the image on the first side of the final document is completed.

  Next, the image reading of the first surface of the final document is completed in this way, and the final document is conveyed to the registration roller side by the reverse rotation of the discharge roller pair 212. Thereafter, the registration sensor 205 is moved to the leading edge of the final document. After a predetermined amount of conveyance from the detection of the leading edge of the document, the read motor 406 and the paper feed motor 416 are stopped. The predetermined amount at this time is “a distance at which the registration roller can securely nip the leading edge of the document and can be conveyed”.

  Next, the read motor 406 is driven in the reverse direction and the paper feed motor 416 is driven in the forward direction to transport the original and wait for the lead sensor 211 to detect the leading edge of the original. Then, as shown in FIG. 7B, when the lead sensor 211 detects the leading edge of the document, the lead motor 406 and the paper feed motor 416 are stopped and a “paper feed completion signal” is transmitted. Thereafter, when the leading end of the final document Gn reaches the image reading position 231, the image reading apparatus 201 is prompted to start image reading when the leading edge of the final document Gn reaches the image reading position 231. ". Note that the image reading apparatus 201 reads an image on the second surface of the document Gn in response to the “image reading start signal”.

  Next, the paper discharge sensor 215 detects the leading edge of the document, the path switching flapper 213 switches to the upper side, and waits for the registration sensor 205 to detect the trailing edge of the document. When the registration sensor 205 detects the trailing edge of the document, the paper feeding motor 416 is stopped. After that, when the discharge sensor 215 detects the trailing edge of the document, the read motor 406 is stopped and Wait for the “document output signal”.

  Next, when the “document discharge signal” is received, the read motor 406 is restarted to resume the document conveyance, and the document discharge sensor 215 detects the trailing edge of the document and conveys a predetermined amount. As shown in FIG. 7C, the document Gn is reliably stacked on the paper discharge tray. After the final document Gn is stacked on the paper discharge tray 108 in this way, the read motor 406 is stopped and a series of operations is completed.

  FIG. 8 is a control block diagram of such an automatic document feeder 101. In FIG. 8, 401 is a CPU (Central Processing Unit). A ROM (read only memory) 402 and a RAM (random access memory) 403 are connected to the CPU 401.

  The ROM 402 stores a control program corresponding to the control procedure shown in FIG. 9 described later, and the RAM 403 stores input data and work data. Further, the separation motor 404, the paper feed motor 416, and the read motor 406 described above are connected to the output port of the CPU 401. Further, the document set sensor 110, the registration sensor 205, the paper discharge sensor 215, the lead sensor 211, the first to third tray sensors 103 to 105, and the width detection sensor 414 are connected to the input port of the CPU 401.

  The CPU 401 as an example of a control unit that controls the image reading operation of the reader unit 202 includes a communication unit 410, and performs serial communication with a CPU (not illustrated) of the image reading apparatus 201 to communicate with the image reading apparatus 201. Thus, control data such as the above-described “original conveyance signal”, “image reading start signal”, “image reading end signal”, “feed completion signal”, and “original discharge signal” are exchanged. Such a CPU 401 executes a control program stored in the ROM 402 based on signals from each sensor, and controls each unit.

  FIG. 9 is a flowchart showing a control flow of the present embodiment. This process shows a part of the program stored in the ROM 402 and is executed by the CPU 401.

  First, when a document feed request (document feed signal) requesting a feed operation for feeding a document from the image reading apparatus 201 to the first-out position is confirmed (Y in S501), the CPU 401 performs the document feed operation. Start (S502). Next, registration (skew) is performed, and when registration is completed (Y in S503), document conveyance is started (S504). Thereafter, it is determined whether or not the document being conveyed reads an image on the front surface (first surface) (S505). If the original is to read an image on the front surface (first surface) (Y in S505), The conveyance of the original is continued (S506). Next, it is confirmed whether or not the document feeding operation is completed (S507). When the document feeding operation is completed (Y in S507), the document conveyance is temporarily stopped (S508).

  Next, a document transport request (document transport signal) for requesting a transport operation for transporting the document from the image reading apparatus 201 from the first-out position to the image reading position is confirmed (S509). If there is a document transport request (S509) Y), the document conveying operation is resumed (S510). Thereafter, it is confirmed whether or not the document has reached the image reading position (S511). When the document has reached the image reading position (Y in S511), an image destination signal (image reading start signal) is output. (S512). As a result, the image reading apparatus 201 reads an image. Note that when the trailing edge of the document passes through the image reading position, that is, when the image reading position ends (Y in S513), the output of the image tip signal is stopped, that is, the image reading end signal is output, thereby the image reading The apparatus 201 ends the image reading.

  Next, in order to reverse the front and back of the document, it is confirmed whether or not the trailing edge of the document has reached the reverse position (S514). If the document has reached the reverse position (Y in S514), the original is conveyed. Is stopped (S515). Thereafter, it is confirmed whether or not image reading on the back side of the document has been performed, that is, whether or not double-sided image reading (back side reading) has ended (S516). If double-sided reading has not ended (S516). N), the document is reversely conveyed (S517).

  Next, when the registration of the reversely conveyed document is completed (Y in S503), the document conveyance is started (S504), and then it is determined that the image on the back side of the conveyed document is read. (S505: N), the document is continuously conveyed (S520). Next, after the original is conveyed by a predetermined distance (Y in S521), it is temporarily stopped (S522), and the forward rotation of the lead roller is started (S523).

  Thereafter, S506 to S515 described above are performed. If it is determined in S516 that the reading of the back side has been completed (Y in S516), the document is reversely conveyed (S525), the document is guided to the re-conveyance path 206, and then the document reaches the stop position. It is confirmed whether or not it has been done (S526), and when the stop position is reached (Y in S526), the reverse conveyance of the document is stopped (S527).

  At this time, it is confirmed whether or not the original is the final original (S528). If the original is not the final original (N in S528), the next original on the original stacking tray is fed to place the next original on the preceding original. Carry them in piles. Then, after the image reading of the first side of the next original is completed, the preceding original is discharged.

  On the other hand, when the image reading of all the documents loaded on the document stacking tray is completed (Y in S528), the final document is discharged to the discharge tray (S529). Stop the motor.

  In this way, the next document is superimposed and conveyed on the preceding document after the images on both sides are read, and the preceding document is discharged to the sheet discharge tray, and the next document is directed to the image reading unit. By doing so, it is inexpensive and the time required to transport all the originals can be shortened. And productivity can be improved by shortening the time required for conveyance of all the originals in this way.

  In the above description, the case where the first surface of the next original is read when the originals are superimposed and conveyed has been described. However, the present invention is not limited to this, and the originals are superimposed and conveyed. , The next document is allowed to pass through the image reading position 231 without performing image reading, and the preceding document is discharged and conveyed at the same time, and then the next document is turned upside down. good.

  In this configuration, the preceding document (first document) reads the image of the document in the order of the first side and the second side, and the next document (second document) is the second side and the first side. The control is to read the image of the document in the order of the faces. Then, the third document that follows the next document is subjected to the same control as the first document, and the remaining document is conveyed.

  In the above description, the case where the document image reading control is performed by the CPU 401 provided in the automatic document feeder 101 has been described. However, the present invention is not limited to this, and the image reading device 201 is not illustrated. The CPU may be used.

1 is a diagram illustrating a schematic configuration of an image reading apparatus including an automatic document feeder as an example of a sheet conveying apparatus according to an embodiment of the present invention. FIG. 3 is a perspective view of the image reading apparatus. FIG. 3 is a first diagram illustrating a document flow when reading an image of a double-sided document in the automatic document feeder. FIG. 7 is a second diagram illustrating the flow of a document when reading an image of a double-sided document in the automatic document feeder. FIG. 9 is a third diagram illustrating the flow of a document when reading an image of a double-sided document in the automatic document feeder. FIG. 9 is a fourth diagram illustrating the flow of a document when reading an image of a double-sided document in the automatic document feeder. FIG. 10 is a fifth diagram illustrating the flow of a document when reading an image of a double-sided document in the automatic document feeder. FIG. 3 is a control block diagram of the automatic document feeder. A part of flowchart which shows the flow of control in the said automatic document feeder. The remaining part of the flowchart which shows the flow of control in the said automatic document feeder.

Explanation of symbols

101 Automatic document feeder (ADF)
102 Document stacking tray 110 Document set sensor 201 Image reading device 202 Reader unit 203 Pickup roller 206 Re-conveyance path 207 Registration roller 208 Conveyance path 212 Discharge roller pair 220 Discharge path 231 Image reading position 401 CPU
G Previous document G1 Next document Gn Final document

Claims (7)

The sheet on which the image is formed on both sides is conveyed to the image reading unit, the sheet on which the image on the first side is read is reversed and conveyed again to the image reading unit, and then the image on the second side is read. In the sheet conveying apparatus in which the sheet is reversed again and discharged to the paper discharge unit,
Sheet conveying means for conveying the sheets one by one from the sheet placing means;
A sheet conveying path for conveying the sheet conveyed by the sheet conveying means to the image reading unit;
A paper discharge path for transporting the sheet whose image has been read by the image reading unit to the paper discharge unit;
A re-conveying passage for branching from the paper discharge passage and reversing the sheet after the image has been read and transporting it again to the sheet transport passage;
With
After the images on both sides of the first surface and the second surface are read, the next sheet conveyed by the sheet conveying unit is superimposed and conveyed on the preceding sheet that is reversed and conveyed to the sheet conveying path. In addition, the preceding sheet conveyed in a superimposed manner is discharged to the sheet discharge unit, and the next sheet is directed from the re-conveyance path to the image reading unit. .   It is provided at a junction of the sheet conveyance path and the re-conveyance path, stops in a state where the preceding sheet is held until the next sheet arrives, and after the next sheet arrives, the preceding sheet and the next sheet The sheet conveying apparatus according to claim 1, further comprising a superimposing and conveying unit that superimposes and conveys the sheet.   The forward sheet, which is provided in the sheet discharge path and is conveyed in a superimposed manner by forward rotation, is discharged to the sheet discharge unit, and then reversely rotated so that the next sheet is directed to the re-conveyance path. The sheet conveying apparatus according to claim 1, further comprising a reversible discharge unit.   An image reading apparatus comprising: an image reading unit; and the sheet conveying device according to claim 1 for conveying a sheet to the image reading unit.   5. The image reading apparatus according to claim 4, further comprising a control unit that is provided in the image reading apparatus main body or the sheet conveying apparatus and controls an image reading operation of the image reading unit.   The image reading apparatus according to claim 5, wherein the control unit controls the image reading unit to read an image of the next sheet conveyed in a state of being superimposed by the overlapping conveyance unit. The control unit controls the image reading unit so that an image reading operation is not performed on the next sheet when the next sheet is conveyed in the overlapped state. Item 6. The image reading apparatus according to Item 5.

Images