JP5582398B2 - Image reading device - Google Patents

Description

  In the present invention, after the original is conveyed to the reading position and the image on the first side is read, the original is turned upside down via the loop-shaped conveyance path, and the original is read in the direction opposite to that when reading the first side. The present invention relates to an image reading apparatus that conveys images to a position and reads an image on a second surface.

  As an example of an image reading apparatus capable of reading on both sides, after a document is conveyed to a reading position and an image on the first surface is read, the document is turned upside down via a loop-shaped conveyance path. Is known to read the image on the second surface by conveying the document in the reverse direction to the reading position. Such an image reading apparatus is different from a configuration in which an image on both sides is read by switching back a document, and conveys a document along a series of document conveyance paths (one pass) via a loop-shaped conveyance path. The images on both sides of the document can be read (see, for example, Patent Document 1).

  For example, a first conveyance roller pair and a second conveyance roller pair are arranged at the entrance and exit of the loop-shaped conveyance path. The first conveying roller pair sandwiches the original after the image on the first surface is read at the reading position and conveys the original to the loop-shaped conveying path. On the other hand, the second transport roller pair sandwiches the document that is turned upside down by being transported along the loop-shaped transport path, and transports the original from the loop-shaped transport path to the reading position.

JP 2010-95364 A

  In the image reading apparatus as described above, there is a case where a phenomenon (so-called “skew”) in which the document is conveyed while being inclined obliquely toward the reading position may occur due to a slight shift in the document conveyance direction. Therefore, the leading edge of the document conveyed to the loop-shaped conveyance path is collided with the second conveying roller pair in a stopped state, thereby aligning the leading edge of the document with the second conveying roller pair and correcting skew of the document. Can be considered.

  However, when the loop-shaped conveyance path between the first conveyance roller pair and the second conveyance roller pair is shorter than the length of the maximum readable document, the trailing edge of the document is corrected during skew correction of the document. May be sandwiched between the first conveying roller pair. In this case, since the skew of the original cannot be corrected satisfactorily, the loop-shaped conveyance path between the first conveyance roller pair and the second conveyance roller pair is longer than the maximum readable original length. Also need to be long. Further, when the first transport roller pair and the second transport roller pair are configured by triple rollers, the first transport roller pair is rotated by the transport force of the transport roller located between the two pairs of rollers. Accordingly, there is a problem that the skew correction itself cannot be performed when the second transport roller pair is also rotated, and therefore it is necessary to lengthen the loop-shaped transport path.

  When the loop-shaped conveyance path is long as described above, a wasteful time occurs between reading the rear end portion of the first surface of the document and starting reading the front end portion of the second surface. There is a problem that reading efficiency deteriorates. In addition, when the loop-shaped conveyance path is long, not only the apparatus is increased in size but also the number of conveyance rollers needs to be increased depending on the case, which may increase the manufacturing cost.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide an image reading apparatus capable of correcting skew feeding of a document with a shorter loop-shaped conveyance path.

  The image reading apparatus according to the present invention conveys a document to a reading position and reads an image on the first surface, then reverses the document through a loop-shaped conveyance path, and reverses the direction when reading the first surface. An image reading apparatus for reading an image on a second surface by conveying an original to the reading position, wherein the loop-shaped conveyance path sandwiches the original after the image on the first surface is read at the reading position. A first conveyance roller pair that conveys the original document that is reversed along the conveyance direction along the loop-shaped conveyance path, and a second conveyance roller pair that conveys the original from the loop-shaped conveyance path to the reading position. And the first conveying roller pair is separated from each other to release the nipping state with respect to the original, and then the leading end of the original conveyed to the loop-shaped conveying path is made to collide with the stopped second conveying roller pair. , To correct the skew of the document Characterized in that it comprises a control unit for.

  According to such a configuration, when correcting the skew of the document, even if the trailing edge of the document passes between the first transport roller pair, the document by the first transport roller pair By canceling the nipping state, the skew of the document can be corrected satisfactorily. Accordingly, the loop-shaped conveyance path between the first conveyance roller pair and the second conveyance roller pair can be made shorter than the length of the maximum readable document. The line can be corrected.

  The control unit controls the first conveyance roller pair to be separated from each other and the nipping state with respect to the document is released after the image on the first surface at the trailing edge of the document is read at the reading position. There may be.

  According to such a configuration, after the image on the first surface at the rear end portion of the document is read at the reading position, the state in which the document is held by the first transport roller pair is released. The paired document holding state is not released. Accordingly, it is possible to prevent the read image from being affected by releasing the nipping state of the document by the first conveying roller pair during reading, and it is possible to read the image satisfactorily.

  The image reading apparatus includes a triple roller including a first roller, a second roller whose outer peripheral surfaces are in contact with the first roller, and a third roller whose outer peripheral surfaces are in contact with the second roller. The first transport roller pair may be composed of the first roller and the second roller, and the second transport roller pair may be composed of the second roller and the third roller.

  According to such a configuration, the second roller and the third roller in the triple roller are used as the second transport roller pair, and the leading edge of the document is caused to collide with the stopped second roller and the third roller. The skew can be corrected. Further, the first roller and the second roller in the triple roller can be used as the first transport roller pair, and the first roller and the second roller can be separated from each other to release the nipping state with respect to the document. Accordingly, the number of transport rollers to be driven can be reduced.

  The triple roller may be disposed downstream of the reading position when reading the first surface of the document and upstream of the reading position when reading the second surface of the document.

  According to such a configuration, the original after the image on the first surface is read at the reading position can be held between the first roller and the second roller and conveyed to the loop-shaped conveyance path. In addition, the original that has been turned upside down by being conveyed along the loop-shaped conveyance path can be conveyed by the second roller and the third roller to the reading position from the loop-shaped conveyance path.

  The control unit may perform control so that the first conveyance roller pair is separated from each other and the nipping state with respect to the document is released immediately before correcting the skew of the document.

  According to such a configuration, the document can be transported to the loop-shaped transport path by the first transport roller pair until just before correcting the skew of the document. Accordingly, it is possible to reliably correct the skew of the document by reliably causing the leading end portion of the document conveyed to the loop-shaped conveyance path to collide with the stopped second conveyance roller pair.

  The controller may be configured to return the first transport roller pair separated from each other to the original state when the transport of the document is resumed after correcting the skew of the document. .

  According to such a configuration, after correcting the skew of the document, the document can be transported by both the first transport roller pair and the second transport roller pair, so that the second surface of the document is read at the reading position. Can be performed satisfactorily.

  The reading position may be different when reading the first side of the document and when reading the second side of the document.

  According to such a configuration, at the time of reading the first surface where the document is conveyed at the reading position toward the loop-shaped conveyance path side, and at the time of reading the second surface where the document is conveyed from the loop-shaped conveyance path side to the reading position. Even when the optimum reading position is different, the images on the first surface and the second surface can be satisfactorily read.

1 is a schematic cross-sectional view illustrating an example of an image reading apparatus according to an embodiment of the present invention. It is a schematic sectional drawing for demonstrating the drive mechanism of a triple roller. FIG. 6 is a schematic cross-sectional view for explaining a mechanism for releasing a state in which the first conveyance roller pair is clamped with respect to a document. 5 is a flowchart illustrating an example of processing by a control unit when reading images on both sides of a document. FIG. 10 is a schematic cross-sectional view showing another embodiment of a mechanism for releasing a state in which the first conveying roller pair is clamped with respect to a document.

  FIG. 1 is a schematic sectional view showing an example of an image reading apparatus according to an embodiment of the present invention. The image reading apparatus can transport a document along the document transport path 10 and read a document image at a reading position 11. More specifically, after the original is conveyed to the reading position 11 and the image on the first side is read, the original is turned upside down, and the original is conveyed to the reading position 11 in the direction opposite to that when reading the first side. Thus, the image on the second surface can be read.

  Documents can be set in a stacked state on a document tray (not shown), and the document is sent out by the pickup roller 12. When a plurality of documents are sent out by the pickup roller 12, only one document is separated by the separation roller 13 and conveyed to the document conveyance path 10. The original is conveyed along the original conveyance path 10 to the reading position 11 by the conveying rollers 14 and 15, and the image on the first surface is read at the reading position 11.

  Reading of a document is performed by a scanner 16 provided at a reading position 11. The scanner 16 emits light from below to the document passing through the reading position 11 and receives reflected light from the document, thereby generating image data based on the amount of received reflected light. A first document sensor 17 is provided upstream of the reading position 11 of the document conveyance path 10 (may be immediately before the conveyance roller 15), and the first document sensor 17 causes the leading edge of the document. After a predetermined time has elapsed since the detection of the image (after transporting a predetermined transport distance), reading of the first surface of the document by the scanner 16 is started.

  The original on which the image on the first surface has been read at the reading position 11 is conveyed to a loop-shaped conveyance path 18 that constitutes a part of the original conveyance path 10. The loop-shaped conveyance path 18 has a shape that extends in a loop shape from the downstream side of the reading position 11 and returns to the reading position 11 again. The original on which the image on the first surface is read at the reading position 11 is turned upside down via the loop-shaped conveyance path 18 and then passes through the reading position 11 in the direction opposite to that when reading the first surface. The image of the second surface is read at the position 11.

  In the present embodiment, the reading position 11 differs between when reading the first side of the document and when reading the second side of the document. More specifically, the reading position (first reading position 111) for reading the image on the first surface of the document is closer to the transport roller 15, and the reading position (first position for reading the image on the second surface of the document). The second reading position 112) is set at a position far from the conveying roller 15. That is, the reading positions 111 and 112 are set on the upstream side with respect to the document conveyance direction both when reading the image on the first side of the document and when reading the image on the second side of the document. Yes.

  When reading the first surface where the document is transported from the reading position 11 toward the loop-shaped transport path 18 side, and when reading the second surface where the document is transported from the loop-shaped transport path 18 side to the reading position 11 The optimum reading position 11 may be different due to the fluttering of the document. Even in such a case, as described above, the reading position 11 is set to the optimum position for reading the first side of the document and for reading the second side of the document, respectively. The images on the first surface and the second surface can be read satisfactorily. However, the reading position 11 is not limited to be different between the reading of the first side of the original and the reading of the second side of the original, but the first side and the second side of the original at the same reading position 11 are not limited. It may be configured to read an image.

  On the downstream side of the reading position 11 (first reading position 111) when reading the first side of the document and on the upstream side of the reading position 11 (second reading position 112) when reading the second side of the document, A triple roller 19 is provided at a position serving as an entrance / exit of the loop-shaped conveyance path 18. The triple roller 19 includes a first roller 191, a second roller 192 whose outer peripheral surfaces are in contact with the first roller 191, and a third roller 193 whose outer peripheral surfaces are in contact with the second roller 192. The second roller 192 is a driving roller that is rotated by a driving force of a motor (not shown), and the first roller 191 and the third roller 193 whose outer peripheral surfaces are in contact with the second roller 192 are the second roller 192. This is a driven roller that rotates with the rotation.

  The first roller 191 and the second roller 192 whose outer peripheral surfaces are in contact with each other are provided in the vicinity of the entrance of the loop-shaped conveyance path 18 and sandwich the document after the image on the first surface is read at the reading position 11 to loop. 1st conveyance roller pair which conveys to the cylindrical conveyance path 18 is comprised. On the other hand, the second roller 192 and the third roller 193 whose outer peripheral surfaces are in contact with each other are provided in the vicinity of the exit of the loop-shaped conveyance path 18, and the originals that are turned upside down are conveyed along the loop-shaped conveyance path 18 A second conveyance roller pair that sandwiches and conveys from the loop-shaped conveyance path 18 to the reading position 11 is configured.

  In the middle of the loop-shaped conveyance path 18, a conveyance roller 20 that conveys a document conveyed to the loop-shaped conveyance path 18 by the first conveyance roller pair 191 and 192 to the second conveyance roller pair 192 and 193 is provided. . A second document sensor 21 is provided immediately before the second conveyance roller pair 192 and 193 in the loop-shaped conveyance path 18, and a predetermined time has elapsed since the leading edge of the document was detected by the second document sensor 21. (After transporting a predetermined transport distance), reading of the second surface of the document by the scanner 16 is started.

  A flexible film 22 is provided at the junction between the inlet and outlet of the loop-shaped conveyance path 18. Due to the action of the film 22, the original after the image on the first surface has been read can be satisfactorily conveyed from the entrance to the loop-shaped conveyance path 18, and turned upside down via the loop-shaped conveyance path 18. The original can be transported satisfactorily from the exit to the reading position 11. As described above, in the present embodiment, a document can be transported along a series of document transport paths 10 (one pass) continuous via the loop-shaped transport path 18 and images on both sides of the document can be read.

  The document from which the image on the second surface has been read at the reading position 11 is conveyed to the branch path 23 branched from the document conveyance path 10. At this time, the rotation direction of the transport roller 15 is reversed. The branch path 23 intersects with the loop-shaped transport path 18 by partially joining and branching. The document conveyed to the branch path 23 is discharged through a conveyance roller 24 provided on the branch path 23 and a conveyance roller 20 provided at a junction between the branch path 23 and the loop-shaped conveyance path 18. To 25 and discharged out of the machine. In the present embodiment, the discharge roller 25 is constituted by a triple roller as shown in FIG. The triple roller functions as a conveyance roller that conveys the original along the loop-shaped conveyance path 18 in the loop-shaped conveyance path 18, and serves as the above-described discharge roller 25 that discharges the original to the outside of the machine in the branch path 23. It is functioning. Guides (not shown) are provided at a portion where the branch path 23 branches from the document transport path 10 and at a downstream branch portion of the transport roller 20 at the junction between the branch path 23 and the loop-shaped transport path 18. The document transport path is appropriately selected by the guide.

  When only the first surface of the document is read, the document on which the image on the first surface is read at the reading position 11 is transported to the loop-shaped transport path 18, and then halfway along the loop-shaped transport path 18. Is conveyed to the discharge roller 25 via the branching path 23 intersecting at, and discharged outside the apparatus.

  In the present embodiment, when reading images on both sides of the document, the leading end of the document that has been read on the first surface at the reading position 11 and conveyed to the loop-shaped conveyance path 18 is stopped by the second conveyance roller in the stopped state. By making it collide with the pair 192, 193, the skew of the original is corrected. After the leading edge of the document is detected by the second document sensor 21, the rotation of the second roller 192, which is the driving roller of the triple roller 19, is stopped, so that the second transport roller pair 192, 193 in the stopped state is stopped. The tip can be made to collide. The second conveying roller pair 192, 193 is stopped for a predetermined time after the leading edge of the original is detected by the second original sensor 21 (stopped only while the predetermined conveying distance is conveyed), and then the second roller 192 is The document is resumed by being rotated again.

  When correcting the skew of the document, the first roller 191 of the triple roller 19 is separated from the second roller 192, whereby the first transport roller pair 191 and 192 are separated from each other, and the nipping state with respect to the document is changed. It is to be released. Such release of the nipping state of the document is effective when the length of the document is longer than the length of the loop-shaped conveyance path 18 between the first conveyance roller pair 191 and 192 and the second conveyance roller pair 192 and 193. Produce. In such a case, after the image on the first surface at the trailing edge of the document is read at the reading position 11, at least when the skew of the document is corrected, the first conveyance roller pair 191, 192 holds the document. The state is to be released.

  According to such a configuration, when correcting the skew of the document, even if the trailing end of the document passes between the first transport roller pair 191 and 192, the first transport roller By canceling the holding state of the original by the pair 191 and 192, the skew of the original can be corrected satisfactorily. Therefore, the loop-shaped conveyance path 18 between the first conveyance roller pair 191 and 192 and the second conveyance roller pair 192 and 193 can be made shorter than the length of the maximum readable document, and a shorter loop. It is possible to correct the skew of the original in the sheet conveyance path 18.

  Further, after the image on the first surface at the rear end portion of the document is read at the reading position 11, the state of nipping the document by the first transport roller pair 191 and 192 is released, so the first transport roller pair 191 during reading. , 192 is not released. Accordingly, it is possible to prevent the read image from being affected by releasing the document holding state by the first conveying roller pair 191 and 192 during reading, and the image can be read satisfactorily.

  In this embodiment, the length of the loop-shaped conveyance path 18 between the first conveyance roller pair 191 and 192 and the second conveyance roller pair 192 and 193 is set to be shorter than the length of the maximum readable document. ing. Further, the length of the original conveyance path 10 from the reading position 11 to the first conveyance roller pair 191 and 192 is set to the loop conveyance path between the first conveyance roller pair 191 and 192 and the second conveyance roller pair 192 and 193. The value obtained by adding the length of 18 is set to be longer than the length of the maximum readable document. As a result, even when scanning images on both sides of the maximum readable document, when the skew of the document is corrected, the holding state of the document trailing edge can be released and the document trailing edge Is not corrected in the state where the image is at the reading position 11. Therefore, it is possible to correct the skew of the original with the shorter loop-shaped conveyance path 18.

  In this embodiment, when the second document sensor 21 detects the leading edge of the document, the first conveying roller pair 191 and 192 are separated from each other, thereby correcting the skew of the document (the leading edge of the document). Is detected by the second document sensor 21), the state in which the document is held by the first transport roller pair 191 and 192 is released. Thus, the document can be transported to the loop-shaped transport path 18 by the first transport roller pair 191 and 192 until just before correcting the skew of the document. Therefore, it is possible to reliably correct the skew of the document by reliably causing the leading end of the document conveyed to the loop-shaped conveyance path 18 to collide with the stopped second conveyance roller pair 192 and 193.

  Further, in the present embodiment, after correcting the skew of the document, when the transport of the document is resumed, the first transport roller pair 191 and 192 which are separated from each other are returned to the original state, and the outer peripheral surfaces of the first transport roller pair are restored. It comes into contact. As a result, the first roller 191 rotates following the rotation of the second roller 192 as the conveyance of the original is resumed, and the original can be held and conveyed by the first conveyance roller pair 191 and 192. It becomes a state. Therefore, after correcting the skew of the document, the document can be transported by both the first transport roller pair 191 and 192 and the second transport roller pair 192 and 193, so that the second surface of the document at the reading position 11 can be transported. Reading can be performed satisfactorily.

  FIG. 2 is a schematic cross-sectional view for explaining the drive mechanism of the triple roller 19. A gear 31 is coaxially attached to a second roller 192 that is a driving roller of the triple roller 19. The gear 31 is connected via a gear 32 to a gear 33 attached to a drive shaft 34 of a motor that is a drive source. Therefore, by driving the motor, the second roller 192 connected to the drive shaft 34 of the motor via the gears 31, 32, 33 rotates, and the first roller whose outer peripheral surface comes into contact with the second roller 192, respectively. The roller 191 and the third roller 193 are configured to rotate.

  In addition to the gears 31, 32, 33, a gear 35 is provided in the drive mechanism of the triple roller 19. The gear 35 does not mesh with the gears 31, 32, 33 when the gears 31, 32, 33 mesh with each other. However, when the gear 32 is displaceable and the gear 32 is displaced as indicated by the broken line in FIG. 2, the gears 32, 33, and 35 are engaged with each other. 33 and 35 are not engaged with each other.

  That is, the gear 32 is in a first state (a state indicated by a one-dot chain line in FIG. 2) meshed with the gear 33 and the gear 31, and a second state (a state indicated by a broken line in FIG. 2) engaged with the gear 33 and the gear 35. Can be displaced. The gear 32 is displaced by driving a solenoid 36 as a displacement means. The operations of the solenoid 36 and the motor described above are controlled by a control unit 40 configured by, for example, a CPU. The control unit 40 is also connected to the first document sensor 17 and the second document sensor 21. However, the displacement means is not limited to the solenoid 36 but may be other means such as an electromagnetic clutch.

  In the first state in which the gears 31, 32, and 33 are engaged, the triple roller 19 is rotated by the driving force of the motor as described above. On the other hand, in the second state in which the gears 32, 33, and 35 are engaged, the triple roller 19 does not rotate, and the nipping state of the first conveying roller pair 191 and 192 with respect to the document is released as the gear 35 rotates. It has become so.

  FIG. 3 is a schematic cross-sectional view for explaining a mechanism for releasing the clamping state of the first conveying roller pair 191 and 192 with respect to the document. When the second state where the gears 32, 33, and 35 are engaged with each other is driven by the solenoid 36, the gear 35 is rotated by the driving force of the motor. The gear 35 is connected via a gear 37 to a driven member 38 for separating the first roller 191 of the triple roller 19 from the second roller 192.

  The gear 37 is a pinion gear, and a rack is formed on the contact surface of the driven member 38 with the gear 37. Therefore, when the gears 35 and 37 are rotated by the driving force of the motor, the driven member 38 is slidably displaced. The driven member 38 is formed with an inclined surface 381 extending in a direction intersecting the sliding direction, and the rotating shaft 194 of the first roller 191 is moved by the inclined surface 381 as the driven member 38 slides. Be able to.

  That is, when the gears 35 and 37 are rotated by the driving force of the motor, the driven member 38 slides, and the rotating shaft 194 of the first roller 191 is moved by the inclined surface 381 of the driven member 38. The first roller 191 is separated from the second roller 192. A tension spring 39 as an urging member is attached to the driven member 38 so as to extend parallel to the sliding direction. Therefore, when the second state in which the gears 32, 33, and 35 mesh with each other is released by driving the solenoid 36, the driven member 38 returns to the original position by the urging force of the tension spring 39. Yes.

  FIG. 4 is a flowchart illustrating an example of processing by the control unit 40 when reading images on both sides of a document. The document sent out from the document tray by the pickup roller 12 is conveyed to the reading position 11 via the document conveying path 10, and the image on the first surface is read at the reading position 11 (step S101). At this time, the scanner 16 reads an image on the first surface of the document at the first reading position 111.

  The document from which the image on the first surface has been read is conveyed to the loop-shaped conveyance path 18. In this state, the gear 32 is in a first state (a state indicated by a one-dot chain line in FIG. 2) where the gear 32 meshes with the gear 33 and the gear 31. Thereafter, the second document sensor 21 provided in the loop-shaped conveyance path 18 detects the leading edge of the document (Yes in Step S102), and when the reading of the first surface of the document is completed (Yes in Step S103), The solenoid 36 is driven so that the gear 32 is engaged with the gear 33 and the gear 35 in a second state (a state indicated by a broken line in FIG. 2).

  As a result, the rotation of the first transport roller pair 191 and 192 and the second transport roller pair 192 and 193 is stopped (step S104), and the nipping state of the first transport roller pair 191 and 192 with respect to the document is released (step S104). Step S105). The skew of the original is corrected by colliding with the second conveying roller pair 192 and 193 stopped in this manner, the leading edge of the original conveyed on the loop-shaped conveyance path 18.

  After that, when a predetermined time has elapsed (Yes in step S106), the solenoid 36 is driven again to be in the first state where the gear 32 is engaged with the gear 33 and the gear 31 (the state indicated by the one-dot chain line in FIG. 2). . As a result, the first conveyance roller pair 191 and 192 are returned to the original state of sandwiching the original (step S107), and the rotation of the first conveyance roller pair 191 and 192 and the second conveyance roller pair 192 and 193 is resumed. (Step S108).

  At this time, the scanner 16 is moved from the first reading position 111 to the second reading position 112 (step S109). Therefore, the image of the second surface of the document conveyed to the reading position 11 by reading the rotation of the second conveying roller pair 192 and 193 is read at the second reading position 112 (step S110). After the image on the second side of the document is read, the scanner 16 is returned from the second reading position 112 to the first reading position 111 (step S111). The original on which the images on both sides are read in this way is conveyed to the branch path 23 and is discharged outside the apparatus via the discharge roller 25.

  FIG. 5 is a schematic cross-sectional view showing another embodiment of a mechanism for releasing the nipping state of the first conveying roller pair 191 and 192 with respect to the document.

  In the example of FIGS. 2 and 3, the driven member 38 is slid through the gear 35 meshing with the gear 32 by displacing the gear 32 with the solenoid 36, and the first roller 191 is moved by the inclined surface 381 of the driven member 38. The configuration for moving the rotary shaft 194 has been described. On the other hand, in the example of FIG. 5, the first roller 191 is directly slid by the solenoid 36, and the first roller 191 is separated from the second roller 192.

  The second roller 192 can be stopped via the clutch 131 controlled by the control unit 40. Note that the control timing and the like by the control unit 40 in this embodiment are the same as those in the above-described embodiment.

  In the above embodiment, the first conveyance roller pair 191 and 192 and the second conveyance roller pair 192 and 193 are constituted by the first roller 191, the second roller 192 and the second roller 193 of the triple roller 19. explained. However, the configuration is not limited to such a configuration, and a configuration in which the first transport roller pair and the second transport roller pair are provided separately may be employed.

DESCRIPTION OF SYMBOLS 10 Document conveyance path 11 Reading position 16 Scanner 17 First document sensor 18 Loop conveyance path 19 Triple roller 21 Second document sensor 23 Branch path 36 Solenoid 40 Control unit 111 First reading position 112 Second reading position 191 First roller 192 2nd roller 193 3rd roller

Claims (5)

After the original is conveyed to the reading position and the image on the first side is read, the original is turned upside down via the loop-shaped conveyance path, and the original is conveyed to the reading position in the direction opposite to that when reading the first side. An image reading device for reading an image on the second surface,
A first roller;
A second roller in contact with the outer peripheral surface of the first roller and rotated by a driving force;
A third roller in contact with the outer peripheral surface of the second roller;
A first conveying roller pair configured by the first roller and the second roller that sandwich the original after the image on the first surface is read at the reading position and convey the original to the loop-shaped conveyance path; ,
Consists of the second roller and the third roller that sandwich the original that has been turned upside down by being conveyed along the loop-shaped conveyance path and convey the original from the loop-shaped conveyance path to the reading position. a second conveying roller pair that,
At least one third transport roller pair provided between the first transport roller pair and the second transport roller pair on the loop transport path;
After the first conveying roller pair is separated from each other and the nipping state with respect to the original is released, the driving of the second roller is stopped, and the original conveyed to the loop conveying path is conveyed by the third conveying roller pair. A control unit that controls to correct the skew of the document by causing the leading end of the document to collide with the second conveyance roller pair in a stopped state .
The length of the loop-shaped conveyance path between the first conveyance roller pair and the second conveyance roller pair is shorter than the length of the document . The first roller, the second roller, and the third roller are downstream of the reading position when reading the first surface of the document and upstream of the reading position when reading the second surface of the document. The image reading apparatus according to claim 1 , wherein the image reading apparatus is disposed in a position. Wherein, immediately prior to correct the skew of the document, according to claim 1 or 2, characterized in that control to release the holding state with respect to the original one another by separating the first conveying roller pair Image reading device. The control unit controls the first transport roller pair in a state of being separated from each other to return to the original state when the transport of the document is resumed after correcting the skew of the document. Item 4. The image reading device according to any one of Items 1 to 3 . And when the first surface reading of the document, at the time of reading of the second side of the document, the image reading apparatus according to any one of claims 1 to 4, wherein said reading position are different from each other.

Images