JP4165544B2 - Sheet material transport device - Google Patents

Description

  In the present invention, a sheet material placing portion on which a sheet material to be subjected to double-side processing is placed and a sheet material discharge portion to which a sheet material subjected to double-side processing is discharged are connected via a processing position by a sheet material conveyance path. , A sheet material conveyance formed by connecting a switchback conveyance path for reversing the leading edge and the trailing edge of the sheet material from the downstream side of the processing position to the upstream side of the processing position at a predetermined position of the sheet material conveyance path It relates to the device.

  2. Description of the Related Art Conventionally, in an image reading apparatus mounted on a copying apparatus, a scanner apparatus, a multi-function apparatus having both a copying function and a scanner function, an ADF (Auto Document) that conveys a document from a sheet feeding tray to a sheet discharging tray via a conveying path. A device equipped with an automatic document feeder called “Feeder” is known. In addition, in order to read a document printed on both sides of the first side and the second side, the leading end and the trailing end of the document are reversed by switching back the document in the middle of conveyance, so that both sides of the document can be read. 2. Description of the Related Art An automatic document feeder that performs conveyance is known (for example, see Patent Document 1).

  FIG. 36 shows a conveyance path of a conventional automatic document conveyance apparatus capable of reading both sides. As shown in the figure, a document P placed on the sheet feed tray 100 with the first surface (first page) facing upward is fed to the conveyance path 102 by the sheet feed roller 101. In the transport path 102, the document P is transported to transport rollers 103 provided as appropriate, and when passing through the reading position X, the first surface of the document P is read by an image reading means such as a CCD or CIS. When the sensor detects the trailing edge of the document P after the first surface is read, the paper discharge roller 104 is stopped in a state where the vicinity of the trailing edge of the document is nipped.

  As shown in FIG. 37, the document P is conveyed to the switchback path 105 by reversely rotating the paper discharge roller 104. The document P enters again from the switchback path 105 to the upstream side of the reading position X of the conveyance path 102. As a result, the leading edge and the trailing edge of the document P are reversed. Then, the document P is transported by the transport roller 103, and when the document P passes through the reading position X, the second surface of the document P is read by the image reading unit. When the sensor detects the trailing edge of the document P after the second surface is read, the paper discharge roller 104 is stopped again with the vicinity of the trailing edge of the document nipped, and then the document P reverses the switchback path 105. Sent. The document P that has entered the conveyance path 102 again from the switchback path 105 is in a state in which the leading edge and the trailing edge are reversed again, that is, the first surface is opposed to the reading position X. Then, the document P is transported through the transport path 102 and discharged onto the paper discharge tray 106 with the first surface facing downward. As a result, both the first side and the second side of the original P are read, and the original P is discharged to the discharge tray 106 in the order in which the original P is stacked on the paper supply tray 100.

  The paper feed roller 101, the transport roller 103, and the paper discharge roller 104 are rotated in a predetermined direction by the driving force transmitted from the motor. The paper feed roller 101 and the conveyance roller 103 are always rotated in one direction, that is, in a direction in which the document P is fed from the upstream side to the downstream side of the conveyance path 102. On the other hand, the paper discharge roller 106 is rotated in both forward and reverse directions to perform switchback conveyance. For example, as shown in FIG. 37, when the document P is nipped between the transport roller 103 and the paper discharge roller 104, the document feed direction of the transport roller 103 matches the document feed direction of the paper discharge roller 104. Need to be. When a document is nipped between the conveyance roller 103 and the discharge roller 104 immediately upstream of the reading position X, the document feed direction of the conveyance roller 103 and the document feed direction of the discharge roller 104 are the same. It must be done. Therefore, a motor for driving the transport roller 103 and a motor for driving the paper discharge roller are provided separately, the transport roller 103 is always rotated in a fixed direction, and the rotation direction of the paper discharge roller 104 is switched at a predetermined timing.

  Further, when a plurality of documents P placed on the sheet feed tray 100 are sequentially transported, it is necessary to form a predetermined gap between the documents P fed into the transport path 102. Accordingly, an electromagnetic clutch is provided in the driving force transmission mechanism to the paper feed roller 101, the rotation transmission to the paper feed roller 101 is cut at a predetermined timing, and the document P placed on the paper feed tray 100 is conveyed in the transport path 102. It is made not to be carried over in the state where it was connected to.

  However, if a motor for driving the paper feed roller 101 and the transport roller 103 and a motor for driving the paper discharge roller 104 are provided separately, and an electromagnetic clutch is provided for cutting off the rotation transmission to the paper feed roller 101, There is a problem that the number of electrical parts increases and the cost of the apparatus increases. In addition, there is a problem that a space for arranging the electrical components is required, and the apparatus is increased in size. On the other hand, a means has been proposed in which a single motor for driving each roller of the automatic document feeder is used (see Patent Document 1).

Japanese Patent No. 3546822

  As described above, in the conveyance path 102 and the switchback path 105, it is necessary to match the document feeding directions with adjacent rollers that simultaneously nip the document P. If each roller is driven by a single motor as shown in Patent Document 1, there are cases where the document feeding direction differs between adjacent rollers. Therefore, it is necessary to cut off the rotation transmission to one of the adjacent rollers that simultaneously nip the originals and that have different document feeding directions. For this purpose, an electromagnetic clutch is provided for transmission of rotation from the motor to the roller (for example, FIG. 4 of Patent Document 1). Further, in order to prevent a plurality of originals from being fed continuously, an electromagnetic clutch is also provided in the paper feed roller (separate roller). Furthermore, electrical actuators such as solenoids are frequently used to move the suction roller up and down and to drive each guide member that guides the document to a predetermined transport path. As described above, when a large number of electromagnetic clutches and electric actuators are used, the timing control becomes complicated. In addition, when a malfunction occurs, it is difficult to identify the cause, and the entire electrical component may be replaced.

  Further, in the apparatus disclosed in Patent Document 1, the rotation direction of the motor is switched when the document is conveyed to the position of the registration roller provided in the conveyance path upstream of the reading position (for example, Patent FIG. 10 of Reference 1). In this apparatus, it is necessary to switch the rotation direction of the motor in the case of single-side reading as well. Along with this, it is necessary to operate the electromagnetic clutch in order to prevent the paper feeding roller (separating roller) that is in pressure contact with the original from rotating in the direction opposite to the feeding direction.

  Therefore, in the apparatus disclosed in Patent Document 1, single-sided reading is performed as compared with a case where switching of the rotation direction of the motor is not necessary in order to ensure switching of the rotation direction of the motor and timing for operating the electromagnetic clutch. The document transport speed at is slow. Further, while the rotation of the motor is in the direction of rotating the paper feed roller in the direction opposite to the feeding direction, the document to be read next cannot be fed to the conveyance path. In addition, when feeding a plurality of documents, the electromagnetic clutch is operated for each page, and the electromagnetic clutch is also operated to switch the rotation of the motor. growing.

  In general, in consideration of the fact that single-sided scanning is used more frequently than double-sided scanning of an original, an automatic document feeder that can perform double-sided scanning has a slower single-sided scanning operation speed than an apparatus that can only transport the original for single-sided scanning. It is not preferable that the operation sound becomes loud.

  The present invention has been made in view of such circumstances, and in a sheet material conveying apparatus capable of conveying for double-sided processing of a sheet material, each roller for conveying a sheet material is driven by a single motor, It is an object of the present invention to provide means capable of realizing driving force transmission to each roller easily and inexpensively, and further reducing the operation sound without impairing the operation speed of single-sided processing.

  (1) A sheet material conveying apparatus according to the present invention includes a sheet material placement unit on which a sheet material to be subjected to double-side processing is placed, a sheet material discharge unit to which the sheet material subjected to double-side processing is discharged, and the sheet A sheet material conveyance path that connects the material placement section and the sheet material discharge section via a processing position, and a leading edge and a trailing edge of the sheet material that are coupled to a predetermined position of the sheet material conveyance path from the downstream side of the processing position And a switchback conveyance path for returning the sheet material to the upstream side of the processing position, and a sheet material placed on the sheet material placement part, provided near the sheet material placement part of the sheet material conveyance path. A feeding unit that sequentially feeds; a sheet material conveying unit that is provided in the sheet material conveying path and conveys the sheet material from the sheet material placing unit to the sheet material discharging unit; and provided in the switchback conveying path. Switch A first guiding posture and a sheet material conveying path for guiding the sheet material to a conveying path in which the sheet material conveying path is continuous at a connecting position between the sheet back conveying means, the sheet material conveying path and the switchback conveying path; A guide means that changes its posture to a second guide attitude for guiding the sheet material to a conveying path that is continuous with the switchback conveying path, and the feeding means and the sheet material that are rotated in both forward and reverse directions. The feeding means is supplied to the feeding means based on a single driving source that applies driving force to the conveying means, the switchback conveying means, and the guiding means, and the rotation of the driving source in either the forward or reverse direction. A first driving force transmitting means for transmitting a driving force in the feeding direction and cutting off the transmission of the driving force to the feeding means based on switching of rotation in the other direction, and a rotational direction of the driving source; The above The second driving force transmitting means for transmitting the driving force in the conveying direction to the material conveying means, and the driving in the pulling direction to the switchback conveying means based on the rotation of the driving source in either the forward or reverse direction A third driving force transmitting means for transmitting a force and transmitting a driving force in the returning direction to the switchback conveying means on the basis of rotation in the other direction; Driving force cutting means for cutting off transmission of driving force from the third driving force transmitting means to the switchback conveying means when switching from rotation to rotation in the other direction and both forward and reverse of the driving source Based on rotation in any one direction of the direction, the guide means is changed to the first guide attitude, and based on rotation in the other direction, the guide means is changed to the second guide attitude. Drive force transmission means and the drive source The single-sided processing conveyance mode that rotates only in one of the forward and reverse directions, and when the leading edge of the sheet material conveyed through the sheet material conveyance path reaches a predetermined position upstream of the processing position. The drive source is switched after the rotation direction of the drive source is switched, the cutting of the driving force by the driving force cutting means is released when the sheet material is drawn into the switchback conveyance path, and the sheet material is drawn into the switchback conveyance path. Drive control means having a double-sided processing conveyance mode for switching the rotation direction.

  A sheet material for performing double-sided processing is placed on the sheet material placement unit. The double-sided processing is, for example, double-sided reading of a sheet material in an image reading apparatus and image recording on both sides of a sheet material in an image forming apparatus. Single-sided processing is, for example, single-sided reading of a sheet material in an image reading apparatus, and image recording on one side of a sheet material in an image forming apparatus. When a single drive source rotates in the forward direction or the reverse direction, a driving force is applied to the feeding unit, the sheet material transport unit, the switchback transport unit, and the guide unit. The forward direction or the reverse direction is a contradictory direction such as clockwise or counterclockwise. The direction of rotation of the drive source is switched by drive control means. The drive control means has a single-sided processing transport mode and a double-sided processing transport mode.

  In the single-sided processing conveyance mode, the drive control unit rotates the drive source only in one of the forward and reverse bidirectional directions. The first driving force transmission means transmits the driving force from the driving source to the feeding means. When the driving source rotates in either the forward direction or the reverse direction, or in the forward direction, the driving force in the feeding direction is transmitted to the feeding unit by the first driving force transmission unit. Thereby, the sheet material is fed to the sheet material conveyance path.

  Sheet material conveying means is provided in the sheet material conveying path. The second driving force transmission means transmits the driving force from the driving source to the sheet material conveying means. The second driving force transmitting means transmits the driving force in the conveying direction to the sheet material conveying means regardless of the rotation direction of the driving source. The sheet material conveying means to which the driving force is transmitted conveys the sheet material fed to the sheet material conveying path toward the sheet material discharging unit. As a result, the sheet material is conveyed through the sheet material conveyance path with one of the front and back surfaces facing the processing position, and is discharged to the sheet material discharge unit.

  In the duplex processing conveyance mode, the drive control unit first rotates the drive source in either the forward or reverse direction. When the driving source rotates in either the forward direction or the reverse direction, or in the forward direction, the driving force in the feeding direction is transmitted to the feeding unit by the first driving force transmission unit. When the rotation of the driving source is switched from the normal direction to the reverse direction, the transmission of the driving force to the feeding unit by the first driving force transmitting unit is cut off. When feeding the sheet material placed on the sheet material placement unit to the sheet material conveyance path, for example, the drive source is rotated in the forward direction. As a result, the driving force in the feeding direction is transmitted to the feeding means, and the sheet material is fed to the sheet material conveyance path. The second driving force transmission means transmits the driving force in the conveying direction to the sheet material conveying means regardless of whether the driving source rotates in the forward direction or the reverse direction. The sheet material conveying means to which the driving force is transmitted conveys the sheet material fed to the sheet material conveying path toward the sheet material discharging unit.

  The drive control means switches the rotation direction of the drive source when the leading edge of the sheet material conveyed through the sheet material conveyance path reaches a predetermined position upstream of the processing position. Suppose that the rotation direction of the drive source is switched from the normal direction to the reverse direction. The first driving force transmission means cuts off the driving force transmission to the feeding means by switching the rotation direction of the driving source. The second driving force transmission means transmits the driving force in the conveying direction to the sheet material conveying means even when the rotation direction of the driving source is switched. Therefore, the sheet material conveyed through the sheet material conveyance path by the sheet material conveyance means is further conveyed along the sheet material conveyance path with the first surface, which is one of the front and back surfaces, facing the processing position.

  A switchback conveyance path is connected to a predetermined position of the sheet material conveyance path. The switchback conveying path is for returning the leading end and the trailing end of the sheet material from the downstream side of the processing position of the sheet material conveying path to the upstream side of the processing position. Guiding means is provided at a connection position between the sheet material conveyance path and the switchback conveyance path. The guiding means guides the sheet material to the first guiding posture for guiding the sheet material to the conveying path where the sheet material conveying path is continuous and the conveying path where the sheet material conveying path and the switchback conveying path are continuous. The posture changes to the second guiding posture.

  The fourth driving force transmission means transmits the driving force from the driving source to the guide means. When the drive source rotates in either the forward direction or the reverse direction, the guide means is changed to the first guide attitude by the fourth drive force transmission means. When the drive source rotates in the other direction, the guide means is changed to the second guide attitude by the fourth driving force transmission means. If the drive source rotates in the forward direction, the guide means is changed in posture to the first guide posture, and if the drive source rotates in the reverse direction, the guide means is changed in posture to the second guide posture, When the drive source is rotated in the reverse direction, the guide means assumes the second guide posture. Therefore, the sheet material that has passed through the processing position is guided to the switchback conveyance path by the guide means.

  The switchback conveyance path is provided with switchback conveyance means for switchback conveyance of the sheet material. The third driving force transmission means transmits the driving force of the driving source to the switchback conveying means. When the drive source rotates in either the forward direction or the reverse direction, the driving force in the pull-in direction is transmitted to the switchback transport unit by the third driving force transmission unit. When the driving force rotates in the other direction, the driving force in the returning direction is transmitted to the switchback conveying unit by the third driving force transmitting unit. When the drive source is switched from rotation in either one of the forward and reverse directions to rotation in the other direction, the driving force cutting means drives the driving force from the third driving force transmitting means to the switchback conveying means. Disconnect the transmission. If the driving source rotates in the forward direction, the third driving force transmitting means transmits the driving force in the returning direction to the switchback conveying means, and if the driving source rotates in the reverse direction, the third driving force transmitting means. Thus, the driving force in the pull-in direction is transmitted to the switchback conveying means. The driving force cutting means cuts off the transmission of the driving force by the third driving force transmitting means when the rotation of the driving source is switched from the normal direction to the reverse direction. When the rotation of the driving source is switched from the normal direction to the reverse direction, the transmission of the driving force by the third driving force transmitting means is cut off.

  The drive control unit releases the cutting of the driving force by the driving force cutting unit when the sheet material is drawn into the switchback conveyance path. Therefore, the driving force in the pull-in direction is transmitted to the switchback conveying unit by the third driving force transmitting unit. The sheet material guided to the switchback conveyance path is drawn into the switchback conveyance path by the switchback conveyance means.

  The drive control means switches the rotation direction of the drive source after the sheet material is drawn into the switchback conveyance path. If the driving source that has been rotated in the reverse direction is switched to the rotation in the forward direction, the driving force in the return direction is transmitted to the switchback conveying unit by the third driving force transmitting unit. Accordingly, the sheet material drawn into the switchback conveyance path is switched back and returned to the upstream side of the processing position of the sheet material conveyance path in a state where the front end and the rear end are reversed. Even when the rotation of the driving source is switched from the reverse direction to the forward direction, the driving force in the conveying direction is transmitted to the sheet material conveying unit by the second driving force transmitting unit. The sheet material returned to the sheet material conveyance path is conveyed toward the sheet material discharge unit by the sheet material conveyance means.

  The drive control means switches the rotation direction of the drive source when the leading edge of the sheet material conveyed through the sheet material conveyance path reaches a predetermined position upstream of the processing position. The second driving force transmission means transmits the driving force in the conveying direction to the sheet material conveying means even when the rotation direction of the driving source is switched. The driving force cutting means cuts off the transmission of the driving force by the third driving force transmitting means when the rotation of the driving source is switched from the normal direction to the reverse direction. Therefore, the sheet material conveyed through the sheet material conveyance path by the sheet material conveyance unit is further conveyed along the sheet material conveyance path with the second surface, which is the other of the front and back surfaces, facing the processing position. Further, the sheet material conveyed through the sheet material conveying path by the sheet material conveying means is not conveyed in the pull-in direction by the switchback conveying means. When the drive source is rotated in the reverse direction, the guide means assumes the second guide posture by the fourth driving force transmission means. Therefore, the sheet material that has passed the processing position is again guided to the switchback conveyance path by the guide means.

  The drive control unit releases the cutting of the driving force by the driving force cutting unit when the sheet material is drawn into the switchback conveyance path. Therefore, the driving force in the pull-in direction is transmitted to the switchback conveying unit by the third driving force transmitting unit. The sheet material guided to the switchback conveyance path is drawn into the switchback conveyance path by the switchback conveyance means.

  The drive control means switches the rotation direction of the drive source after the sheet material is drawn into the switchback conveyance path. If the driving source that has been rotated in the reverse direction is switched to the rotation in the forward direction, the driving force in the return direction is transmitted to the switchback conveying unit by the third driving force transmitting unit. Therefore, the sheet material drawn into the switchback conveyance path is switched back and conveyed in a state where the front end and the rear end are reversed again, that is, in a state where the sheet material is first fed to the sheet material conveyance path. It is returned to the upstream side of the processing position of the road. Even when the rotation of the driving source is switched from the reverse direction to the forward direction, the driving force in the conveying direction is transmitted to the sheet material conveying unit by the second driving force transmitting unit. The sheet material returned to the sheet material conveyance path is conveyed toward the sheet material discharge unit by the sheet material conveyance unit, and is discharged to the sheet material discharge unit.

  When it is not necessary to match the order of the sheet material placed on the sheet material placement unit and the order of the sheet material discharged to the sheet material discharge unit, the second surface is opposed to the processing position. After the sheet material is conveyed, the sheet material may be discharged to the sheet material discharging unit without entering the switchback conveyance path again.

  (2) The first driving force transmission means meshes with the first transmission gear that transmits the driving force from the driving source, the sun gear that meshes with the first transmission gear, and the sun gear. The first planetary gear, the second transmission gear that is engaged with the first planetary gear to transmit the driving force to the feeding means, and the first planetary gear are pivotally supported to support the first planetary gear. The planetary gear is engaged with the second transmission gear so that the planetary gear is separated from the second transmission gear. And a locking member that holds the disengaged posture separated from the second transmission gear.

  Thereby, a 1st drive force transmission means is realizable, without using an electromagnetic clutch.

  (3) Further, the driving control means is a locking member for the first driving force transmission means when feeding the plurality of sheet materials stacked on the sheet material placement section to the sheet material conveyance path. The locking of the rotating member may be released.

  Thereby, when feeding the sheet material placed on the sheet material placing portion, it is possible to transmit the driving force to the feeding means.

  (4) The feeding means is a feeding roller that presses against the sheet material placed on the sheet material placement portion and rotates based on the driving force transmitted by the first driving force transmission means. And a clutch that transmits a driving force to the feeding roller and allows the feeding roller to idle in a predetermined range, and the sheet material conveying means is configured to provide a sheet at a predetermined position in the sheet material conveying path. A sheet material conveying roller that conveys the sheet material in a predetermined direction by rotating on the basis of the driving force transmitted by the second driving force transmitting means, and in contact with the material; the first driving force The transmission means transmits the driving force from the driving source so that the feeding roller has a lower peripheral speed than the peripheral speed of the sheet material conveying roller rotated by the second driving force transmission means. There may be.

  The sheet material is fed to the sheet material conveyance path when the feeding roller is pressed against the sheet material placed on the sheet material placing portion and rotates. When the sheet material conveyance roller rotates in pressure contact with the sheet material in the sheet material conveyance path, the sheet material is conveyed through the sheet material conveyance path. The sheet material conveying roller is rotated at a predetermined peripheral speed when the driving force of the driving source is transmitted by the second driving force transmitting means. The feeding roller is rotated at a lower peripheral speed than the sheet material conveying roller by the driving force of the driving source being transmitted by the first driving force transmitting means.

  When the sheet material fed from the sheet material placement unit to the sheet material conveyance path is pressed against both the feeding roller and the sheet material conveyance roller, the sheet material is conveyed at a peripheral speed of the sheet material conveyance roller. The feeding roller is rotated at the peripheral speed of the sheet material transport roller by the sheet material transported at the peripheral speed of the sheet material transport roller. The feed roller is provided with a clutch. The clutch allows the feeding roller to idle in a predetermined range. Therefore, the fed feeding roller rotates idle so as to advance in the rotation direction of the shaft.

  When the sheet material conveyed by the sheet material conveying roller is completely fed to the sheet material conveying path, the sheet material is separated from the feeding roller. When a plurality of sheet materials are stacked on the sheet material placement unit, the feeding roller presses the sheet material to be fed next. The first driving force transmission means transmits the driving force from the driving source to the clutch. However, the clutch does not transmit the driving force to the feeding roller by the amount of idling previously. Accordingly, the sheet material to be fed next stops in a state of being in pressure contact with the feeding roller. During this time, the previous sheet material is conveyed through the sheet material conveyance path, whereby a predetermined gap is formed between the previous sheet material and the sheet material to be fed next. When the clutch is rotated by the amount of idling previously, the clutch transmits a driving force to the feeding roller. When the feeding roller rotates, the sheet material to be fed next is fed to the sheet material conveyance path.

  Thus, each time a plurality of sheet materials are fed, the plurality of sheet materials are continuously separated with a predetermined gap without releasing the locking of the rotating member by the locking member of the first driving force transmission means. Can be conveyed.

  (5) Further, the feeding means further swings so as to come into contact with and separate from the sheet material placed on the sheet material placing portion based on the driving force transmitted by the first driving force transmission means. An arm that moves, and a suction roller that is pivotally supported on the distal end side of the arm and that is rotated based on the driving force transmitted by the first driving force transmission unit; Further includes a second planetary gear meshing with the sun gear, and the second planetary gear is pivotally supported by the rotating member, and the rotating member rotates in one direction to rotate the second planetary gear. The gear is disengaged from the second transmission gear, and the first planetary gear is engaged with the second transmission gear, and the second planetary gear is engaged with the second transmission gear by rotating in the other direction. And disengaging the first planetary gear from the second transmission gear. Thus, the sun gear is provided so as to be rotatable coaxially, and the locking member is locked to the rotating member so that the first planetary gear and the second planetary gear are the second transmission gear. The drive control means is configured to hold the first driving force after all the sheet materials stacked on the sheet material placement unit are discharged to the sheet material discharge unit. The rotation of the driving source may be switched by releasing the locking of the rotating member by the locking member of the transmission means.

  The drive control means releases the locking of the rotating member by the locking member of the first driving force transmitting means after all the sheet materials stacked on the sheet material placing section are discharged to the sheet material discharging section. The direction of rotation of the drive source is switched.

  When the drive source rotates in either the forward direction or the reverse direction, or in the forward direction, the first planetary gear meshes with the second transmission gear, and the driving force in the feeding direction is applied to the feeding roller. Communicated. Further, based on the driving force in the feeding direction, the arm swings so as to contact the sheet material placed on the sheet material placing portion, and the suction roller pivotally supported at the tip of the arm presses against the sheet material. Then rotate. In response to the rotation of the suction roller and the feeding roller, the sheet material is fed to the sheet material conveyance path. When the rotation direction of the drive source is switched from the forward direction to the reverse direction, the first planetary gear is disengaged from the second transmission gear, and the second planetary gear meshes with the second transmission gear. Since the locking of the rotating member by the locking member is released, the rotating member is not held in the detached posture. Thereby, the driving force in the direction opposite to the feeding direction is transmitted to the feeding roller. Based on the driving force in the opposite direction, the arm swings in a direction away from the sheet material placement surface, and the suction roller pivotally supported at the tip of the arm separates from the sheet material placement surface. Therefore, it is possible to insert the sheet material from the sheet material placement portion to the sheet material conveyance path to the lower side of the suction roller.

  As described above, according to the sheet material conveying device of the present invention, it is possible to realize single-sided processing conveyance and double-sided processing conveyance by a single drive source. Further, in the single-sided processing conveyance mode, the rotation direction of the drive source cannot be switched, so that high-speed and stable sheet material conveyance is realized. Further, since it is not necessary to release the locking of the rotating member of the first driving force transmission means every time a plurality of sheet materials are fed, there is an advantage that the operation noise during sheet material conveyance can be reduced.

  Embodiments of the present invention will be described below with reference to the drawings as appropriate. In addition, this embodiment is only an example of this invention, and it cannot be overemphasized that embodiment can be changed suitably in the range which does not change the summary of this invention.

  FIG. 1 shows a main configuration of an image reading apparatus 1 according to an embodiment of the present invention. The image reading device 1 is, for example, a copy device, a facsimile device, a scanner device, a multi-function device (MFD: Multi Function Device) that is integrally provided with a copy function, a facsimile mechanism, a scanner function, etc. This is realized as an image reading unit for performing the above.

  As shown in FIGS. 1 and 6, the image reading apparatus 1 has an auto document feeder (ADF) that is an automatic document feeding mechanism with respect to a document placing table 2 that functions as an FBS (Flatbed Scanner). A document cover 4 having 3 is attached so as to be openable and closable via a hinge on the back side (back of the paper surface). The ADF 3 constitutes a sheet material conveying apparatus according to the present invention. In this embodiment, the sheet material is used as a document, and the sheet material conveying apparatus according to the present invention is realized as ADF3. However, the sheet material conveying apparatus according to the present invention is applied to an image forming apparatus using the sheet material as recording paper. It can also be realized as a sheet material conveying apparatus.

  As shown in FIG. 1, platen glasses 20 and 21 are arranged on the top surface of the document table 2 that faces the document cover 4. When the document cover 4 is opened, the platen glasses 20 and 21 are exposed as the upper surface of the document table 2. When the document cover 4 is closed, the entire upper surface of the document table 2 including the platen glasses 20 and 21 is covered. An image reading unit 22 (image reading means) is built in the document placing table 2 so as to face the platen glasses 20 and 21.

  The platen glass 20 is used to place a document when the image reading apparatus 1 is used as an FBS, and is made of, for example, a transparent glass plate. An opening for exposing the platen glass 20 is formed at the center of the upper surface of the document placing table 2, and an area of the platen glass 20 exposed from the opening becomes an original reading area in the FBS.

  The platen glass 21 is a reading position (processing position) when the ADF 3 of the image reading apparatus 1 is used, and is made of, for example, a transparent glass plate. An opening for exposing the platen glass 21 is formed at the reading position of the document table 2. The platen glass 21 exposed from the opening is extended in the depth direction of the image reading apparatus 1 corresponding to the length of the image reading unit 22 in the main scanning direction.

  A positioning member 23 is interposed between the platen glass 20 and the platen glass 21. The positioning member 23 is a long flat plate-like member that extends in the depth direction of the image reading apparatus 1, similarly to the platen glass 21. The positioning member 23 is used as a document positioning reference when a document is placed on the platen glass 20 which is a document placement surface in the FBS. Therefore, on the upper surface of the positioning member 23, a display indicating the center position and both end positions of various document sizes such as A4 size and B5 size is written. On the upper surface of the positioning member 23, a guide surface is formed that deflects the document passing over the platen glass 21 by the ADF 3 and returns it to the ADF 3.

  The image reading unit 22 is a so-called image sensor that irradiates a document with light from a light source through the platen glasses 20 and 21, collects reflected light from the document on a light receiving element by a lens, and converts it into an electrical signal. As the image reading unit 22, for example, a contact type CIS (Contact Image Sensor) image sensor or a reduction optical system CCD (Charge Coupled Device) image sensor can be used. The image reading unit 22 is provided so as to be able to reciprocate below the platen glasses 20 and 21 by a belt drive mechanism that is a scanning mechanism, and reciprocates in parallel with the platen glasses 20 and 21 by receiving the driving force of the carriage motor. .

  The document cover 4 is provided with an ADF 3 that continuously conveys documents from the paper feed tray 30 (sheet material placement unit) to the paper discharge tray 31 (sheet material ejection unit) through the document conveyance path 32 (sheet material conveyance path). Yes. In the conveyance process by the ADF 3, the document passes through the reading position on the platen glass 21, and the image reading unit 22 waiting under the platen glass 21 reads the image of the document.

  As shown in FIGS. 1 and 6, the document cover 4 is provided with a paper feed tray 30 and a paper discharge tray 31 in two upper and lower stages with the paper feed tray 30 as an upper side. A document for reading an image by the ADF 3 is placed on the paper feed tray 30. A plurality of originals are placed on the paper supply tray 30 so that the front end in the paper supply direction is inserted into the original conveyance path 32 in a stacked state with the first surface facing upward. The protective wall 26 is formed by bending the back side of the sheet feeding tray 30 downward. The lower end of the protective wall 26 is connected to the upper surface of the document cover 4. The protective wall 26 prevents the document on the paper discharge tray 31 from falling when the document cover 4 is opened with respect to the document table 2. A cutout 27 is formed in a part of the casing of the ADF 3 below the front side of the apparatus of the paper feed tray 30. The cutout 27 enhances the visibility of the document discharged from the discharge tray 31 from the front side of the apparatus. In particular, a small-size document is difficult to be visually recognized by the paper feed tray 30, but the space between the paper feed tray 30 and the paper discharge tray 31 is widened by the notch 27. Especially enhanced.

  The paper discharge tray 31 is located at the lower side of the paper feed tray 30 in the vertical direction, and is integrally formed on the upper surface of the document cover 4. The document that has been image-read and discharged from the ADF 3 is held so as to be stacked on the discharge tray 31 with the first side facing down while being separated from the document on the sheet feed tray 30. Both side portions 28 of the paper discharge tray 31 on the front side and the rear side of the apparatus have slopes that bulge upward toward both sides. By the both side portions 28, when the document discharged to the paper discharge tray 31 is taken out, the document can be pulled out by sliding along the slopes of the both side portions 28 while pressing the document from above. It is easy to take out the document from the tray 31.

  As shown in FIG. 1, in the ADF 3, a document having a substantially U shape in the horizontal direction in a longitudinal sectional view so as to connect a paper feed tray 30 and a paper discharge tray 31 through a reading position on the platen glass 21. A conveyance path 32 is formed. The document transport path 32 is continuously formed as a passage having a predetermined width through which a document can pass by members, guide plates, guide ribs, and the like constituting the ADF main body. In this way, the paper feed tray 30 and the paper discharge tray 31 are provided in two upper and lower stages, and the document conveying path 32 having a substantially U shape in the horizontal direction is formed so as to connect them. The width can be reduced to reduce the size.

  The document transport path 32 extends from the paper feed tray 30 to one end side (the left side in the figure) of the document cover 4 and is then curved so as to be reversed downward to reach the reading position on the platen glass 21. A longitudinal sectional view extending from the sheet to the sheet discharge tray 31 is a substantially U shape in the horizontal direction. The document conveyance path 32 can be broadly divided into a substantially U-shape and curved so that the upper part 32A and the lower part 32C forming two straight upper and lower linear parts, and the upper part 32A and the lower part 32C are continuous. It consists of three parts with the curved part 32B. The document conveyance path 32 is used as a document conveyance path in common with single-sided reading and double-sided reading of a document by the ADF 3.

  In the vicinity of the paper feed tray 30 in the document transport path 32, a feeding unit for sequentially feeding the documents placed on the paper feed tray 30 is provided. The document transport path 32 is provided with document transport means for transporting documents from the paper feed tray 30 to the paper discharge tray 31. Specifically, as shown in the drawing, a feeding means is constituted by a suction roller 33 and a separation roller 34 (feeding roller) provided in the document conveying path 32, respectively, and the conveying rollers 35A, 35B, 35C, 35D and the discharge rollers are provided. A document conveying means is constituted by a paper roller 36 (sheet material conveying roller) and a pinch roller 37 in pressure contact therewith. A driving force is transmitted from a single motor 67 (drive source, see FIG. 5) to each roller constituting the feeding unit and the document conveying unit. A driving force transmission mechanism to each roller will be described later. The

  As shown in the drawing, a suction roller 33 and a separation roller 34 are provided in the vicinity of the uppermost stream of the document conveyance path 32. The suction roller 33 is rotatably provided at the distal end portion of the arm 29 that is pivotally supported on the shaft 111 (see FIG. 12) that pivotally supports the separation roller 34. The separation roller 34 is rotatably provided at a position separated from the suction roller 33 in the paper feeding direction so as to come into contact with the opposing surface (document placement surface) of the document conveyance path 32. The suction roller 33 and the separation roller 34 are rotated by the driving force transmitted from the motor 67, and the arm 29 is also oscillated by the driving force transmitted from the motor 67. The suction roller 33 and the separation roller 34 have the same diameter and are rotated at the same peripheral speed. A separation pad that presses against the roller surface of the separation roller 34 and separates the document by friction is disposed at a position facing the separation roller 34.

  The conveyance rollers 35A, 35B, 35C, and 35D are disposed at different positions on the document conveyance path 32, respectively. In the present embodiment, a conveyance roller 35A is disposed immediately downstream of the separation roller 34, a conveyance roller 35B is disposed in the upper portion 32A of the document conveyance path 32, and the lower portion 32C of the document conveyance path 32 is. A conveying roller 35C is disposed immediately upstream of the reading position, and a conveying roller 35D is disposed in the lower portion 32C of the document conveying path 32 and immediately downstream of the reading position. This arrangement is an example, and the number and arrangement of the transport rollers 35A, 35B, 35C, and 35D can be changed as appropriate.

  A pinch roller 37 is provided at a position facing each of the transport rollers 35A, 35B, 35C, and 35D. Each pinch roller 37 is pressed against the roller surface of each conveying roller 35 by its shaft being elastically biased by a spring. If each conveyance roller 35A, 35B, 35C, 35D rotates, it will follow and the pinch roller 37 will also rotate. Each pinch roller 37 presses the document against each conveyance roller 35, and the rotational force of each conveyance roller 35A, 35B, 35C, 35D is transmitted to the document.

  The paper discharge roller 36 is disposed in the vicinity of the most downstream side of the document conveyance path 32, and is driven to rotate by the driving force transmitted from the motor, similarly to the conveyance rollers 35A, 35B, 35C, and 35D. A pinch roller 37 is also provided at a position facing the paper discharge roller 36, and the pinch roller 37 is elastically biased by a spring and pressed against the paper discharge roller 36.

  A switchback path 39 is coupled to a coupling position 38 of the lower portion 32C of the document conveyance path 32. The switchback path 39 retransmits a document whose first surface has been read at the reading position from the downstream side to the upstream side of the document conveyance path 32 by reversing the leading end and the trailing end when performing double-sided reading. Is to do. The switchback path 39 extends obliquely upward from the connection position 38 toward the upper side of the paper feed tray 30 and intersects with the upper portion 32 </ b> A of the document conveyance path 32. The document that is switched back and conveyed from the intersection position 40 between the upper portion 32A and the switchback path 39 is returned to the document conveyance path 32.

  A terminal end 41 of the switchback path 39 is opened on the upper surface of the ADF 3. A document support portion 42 is formed on the side of the paper feed tray 30 from the end 41 of the switchback path 39 so as to continue from the end 41. The document support portion 42 is for supporting the document protruding from the end 41 of the switchback path 39, and forms the upper cover 6 (see FIG. 6) of the ADF 3 above the paper feed roller 33 and the separation roller 34. ing. The upper cover 6 is formed so as to cover the entire ADF 3 including the paper feed roller 33 and the separation roller 34. The document support portion 42 configured as the upper cover 6 extends from the terminal end 41 toward the paper feed tray 30 side to the upstream side from the paper feed position by the paper feed roller 33 and the separation roller 34. As a result, in duplex reading, the document that enters the switchback path 39 and protrudes from the terminal end 41 to the outside of the ADF 3 is supported on the document support unit 41. The document does not hang down further downstream (left side in the figure), and the original is prevented from being disturbed at the paper feed position.

  A switchback roller 43 is disposed closer to the terminal end 41 than the crossover position 40 of the switchback path 39. The switchback roller 43 is driven to rotate in both forward and reverse directions when the driving force from the motor 67 is transmitted. A pinch roller 44 is provided at a position facing the switchback roller 43. The pinch roller 44 is pressed against the roller surface of the switchback roller 43 with its shaft elastically biased by a spring, and rotates in accordance with the rotation of the switchback roller 43. The document is pressed against the switchback roller 43 by the pinch roller 44, and the rotational force of the switchback roller 43 is transmitted to the document. The switchback roller 43 and the pinch roller 44 realize a switchback conveying means for switchback conveying the document.

  In the present embodiment, the switchback path 39 connected to the connecting position 38 on the downstream side of the reading position of the document transport path 32 is crossed with the upper portion 32A of the document transport path 32, and ends from the cross position 40. Although the switchback roller 43 is provided on the 41 side, the conveyance path of the switchback path 39 is arbitrary, and is connected to a predetermined position of the document conveyance path 32 so that the leading edge and the trailing edge of the document are arranged downstream from the reading position. Can be changed as appropriate, as long as it is reversed and returned to the upstream side of the reading position.

  As shown in FIGS. 1 and 2, a guide flap 46 and a guide flap 47 for guiding the document to a desired conveyance path are disposed at the intersection position 40. The guide flap 46 rotates within a predetermined range around a shaft 48 provided at a corner (lower left side in the figure) between the reading position side of the document conveying path 32 and the connection position 38 side of the switchback path 39 at the crossing position 40. It is arranged to be possible. The guide flap 46 is a blade-shaped flat plate, and its tip protrudes to the crossing position 40. In the drawing, only one guide flap 46 is shown, but a plurality of guide flaps 46 of the same shape are provided at predetermined intervals in the width direction of the document conveying path 32, and the plurality of guide flaps 46 are rotated together. Moved.

  The guide flap 46 changes its posture between a third guide posture shown by a solid line in FIG. 2 and a fourth guide posture shown by a two-dot chain line by rotating about a shaft 48. For example, the guide flap 46 is rotated downward from the third guiding posture by being brought into contact with the guide member of the document conveying path 32 or the switchback path 39, and upward from the fourth guiding posture. Rotation is restricted. When the guide flap 46 is in the third guiding position, the conveyance path from the paper feed tray 30 side (right side in the figure) to the reading position side (left side in the figure) of the document conveyance path 32 continues and from the document conveyance path 32. The conveyance path to the connection position 38 side (the lower side in the figure) of the switchback path 39 is closed. As a result, the document that has reached the crossover position 40 from the paper feed tray 30 side of the document transport path 32 is allowed to enter the reading position side of the document transport path 32 and is moved to the connection position 38 side of the switchback path 39. Entering is stopped. Further, the document that has reached the crossover position 40 from the terminal end 41 side (the upper side in the figure) of the switchback path 39 is allowed to enter the reading position side of the document transport path 32, and the connection position 38 side of the switchback path 39. Entry to is stopped.

  When the guide flap 46 is in the fourth guiding posture, the conveyance path from the connection position 38 side of the switchback path 39 to the terminal end 41 side continues, and the document conveyance path 32 from the connection position 38 side of the switchback path 39. The conveyance path to the reading position side is closed. As a result, the document that has reached the crossover position 40 from the connection position 38 side of the switchback path 39 is allowed to enter the terminal end 41 side of the switchback path 39 and enters the reading position side of the document transport path 32. It is restrained.

  Switching of the conveyance path by the guide flap 46 is performed by contacting the original. The guide flap 46 is always in the third guiding posture shown by a solid line in FIG. When the document conveyed on the switchback path 39 from the coupling position 38 toward the crossing position 40 abuts against the guide flap 46, the guide flap 46 is rotated so as to be pushed upward in FIG. The fourth guide posture is indicated by the dotted line. On the other hand, the document conveyed to the crossover position 40 from the terminal end 41 side of the switchback path 39 abuts on the guide flap 46, but the guide flap 46 is restricted from rotating downward from the third guiding posture. Therefore, the document is guided by the guide flap 46 and enters the upper portion 32A of the document transport path 32 to the reading position side. The blade shape of the guide flap 46 is easily changed in posture by the contact of the document conveyed from the connection position 38 side of the switchback path 39 to the crossover position 40, and is conveyed from the terminal end 41 side of the switchback path 39 to the crossover position 40. A shape is adopted in which a document to be guided is easily guided to the reading position side of the document transport path 32. As described above, if the posture of the guide flap 46 is changed by the contact of the document, it is not necessary to positively change the posture of the guide flap 46 by applying a driving force from the motor 67. A guide flap 46 can be realized.

  The guide flap 47 rotates in a predetermined range around a shaft 49 provided at a corner (upper right side in the figure) between the paper feed tray 30 side of the document conveyance path 32 and the terminal end 41 side of the switchback path 39 at the crossover position 40. It is arranged to be movable. The guide flap 47 is a blade-shaped flat plate, and its tip protrudes to the crossing position 40. Although only one guide flap 47 is shown in the figure, a plurality of guide flaps 47 having the same shape are provided at predetermined intervals in the width direction of the document conveying path 32, and the plurality of guide flaps 47 are rotated together. Moved.

  The guide flap 47 changes its posture between a fifth guide posture shown by a solid line in FIG. 2 and a sixth guide posture shown by a two-dot chain line by rotating around the shaft 49. The guide flap 47 rotates, for example, from the fifth guide posture to the right and rotates upward from the sixth guide posture by contacting the guide member of the document transport path 32 or the switchback path 39. It is regulated to move. When the guide flap 47 is in the fifth guide posture, the conveyance path from the terminal end 41 side of the switchback path 39 to the reading position side of the document conveyance path 32 continues, and from the connection position 38 side of the switchback path 39. The conveyance path to the paper feed tray 30 side of the document conveyance path 32 is closed. As a result, the document that has reached the crossover position 40 from the end 41 side of the switchback path 39 is allowed to enter the reading position side of the document transport path 32 and is prevented from entering the paper feed tray 30 side. The Also, the document that has reached the crossover position 40 from the connection position 38 side of the switchback path 39 is allowed to enter the terminal end 41 side of the switchback path 39 and enters the paper feed tray 30 side of the document transport path 32. To be stopped.

  When the guide flap 47 is in the sixth guiding posture, the conveyance path from the paper feed tray 30 side to the reading position side of the document conveyance path 32 continues and the switchback is performed from the paper feed tray 30 side of the document conveyance path 32. The conveyance path to the end 41 side of the path 39 is closed. As a result, the document that has reached the crossing position 40 from the paper feed tray 30 side of the document transport path 32 is allowed to enter the reading position side of the document transport path 32 and enters the end 41 side of the switchback path 39. To be stopped.

  Switching of the conveyance path by the guide flap 47 is performed by contacting the original. The guide flap 47 is always in the fifth guiding posture shown by a solid line in FIG. 2 due to its own weight or receiving the biasing force of an elastic member such as a spring. When the document conveyed from the sheet feeding tray 30 side of the document conveying path 32 comes into contact with the guide flap 47, the guide flap 47 is rotated so as to be pushed to the left side in the drawing, and is indicated by a two-dot chain line in FIG. It becomes the 6th guidance posture. On the other hand, even if the document conveyed from the connection position 38 side of the switchback path 39 to the crossing position 40 comes into contact with the guide flap 47, the guide flap 47 does not rotate to the right from the fifth guide posture. Therefore, the document is guided by the guide flap 47 and enters the end 41 side of the switchback path 39. The blade shape of the guide flap 47 is likely to change its posture due to the contact of the document transported from the paper feed tray 30 side of the document transport path 32 to the crossover position 40, and from the connection position 38 side of the switchback path 39 to the crossover position 40. A shape in which the conveyed document is easily guided to the end 41 side of the switchback path 39 is employed. As described above, if the posture of the guide flap 47 is changed by the contact of the document, it is not necessary to positively change the posture of the guide flap 47 by applying a driving force from a motor or the like. A guide flap 47 can be realized.

  As shown in FIGS. 1 and 3, a guide flap 50 is disposed at the connection position 38. The guide flap 50 is disposed so as to be rotatable about a shaft 51, and is shown by a first guiding posture and a two-dot chain line indicated by a solid line in FIG. The second guide posture is rotated. The guide flap 50 rotates, for example, from the first guide posture to the upper side and from the second guide posture to the lower side by being brought into contact with the guide member of the document conveyance path 32 or the switchback path 39. Rotation is restricted. When the guide flap 50 is in the first guiding posture, the conveyance path from the reading position side (left side in the figure) of the document conveyance path 32 to the discharge tray 31 side (right side in the figure) continues. As a result, the document that has passed through the reading position is guided through the lower portion 32 </ b> C of the document transport path 32 toward the discharge tray 31 at the connection position 38. When the guide flap 50 is in the second guide posture, the conveyance path from the downstream side of the reading position of the lower portion 32C of the document conveyance path 32 to the switchback path 39 continues. As a result, the document that has passed the reading position is guided through the connection position 38 so as to enter the switchback path 39. In this way, the guide flap 50 is disposed so that the document can be guided to either the document transport path 32 or the switchback path 39 at the connection position 38. In the drawing, only one guide flap 50 is shown, but a plurality of guide flaps 50 of the same shape are provided at predetermined intervals in the width direction of the document conveying path 32, and the plurality of guide flaps 50 are integrated. Is rotated.

  As shown in FIG. 1, the document transport path 32 and the switchback path 39 are provided with a plurality of sensors for detecting document transport. Specifically, a first front sensor 52 and a second front sensor 53 are disposed on the upstream side and the downstream side of the separation roller 34 in the document conveyance path 32, respectively, and on the upstream side of the reading position. A rear sensor 54 is provided. A switchback sensor 55 is disposed between the connection position 38 and the crossover position 40 of the switchback path 39. Each of these sensors is a so-called optical sensor and has the same configuration except that the shape of the detector is different depending on the position to be detected. Therefore, the configuration will be described by taking the first front sensor 52 as an example.

  As shown in FIG. 4, the first front sensor 52 protrudes from the lower surface of the document conveyance path 32 and rotates to retract from the document conveyance path 32 by contacting the document, and the detector The photo interrupter 57 detects the rotation of 56. The detector 56 is integrally formed with a shield 58 that is detected by a photo interrupter 57 and is provided so as to be rotatable about a shaft 59. The detector 56 is elastically biased in a clockwise direction in the drawing by a biasing means such as a spring (not shown) to a position where the detector 56 protrudes into the document conveying path 32. In a state where no external force is applied to the detector 56, the detector 56 protrudes into the document conveyance path 32, and the shielding portion 58 is located between the light emitting portion and the light receiving portion of the photo interrupter 57, as shown by the solid line in the figure. Thereby, the light transmission of the photo interrupter 57 is interrupted, and the first front sensor 52 is turned off.

  When a document is placed on the paper feed tray 30, the document contacts the detector 56 and rotates so that the detector 56 is retracted from the document transport path 32. The shielding portion 58 is also rotated together with the detector 56, and the shielding portion 58 is separated from the space between the light emitting portion and the light receiving portion of the photo interrupter 57 as shown by a two-dot chain line in the figure. Thereby, the light transmission of the photo interrupter 57 is not interrupted, and the first front sensor 52 is turned on. Whether the document is placed on the paper feed tray 30 is detected by turning on / off the first front sensor 52.

  The second front sensor 53 disposed immediately downstream of the separation roller 34 is for detecting the leading edge or trailing edge of the document fed to the document conveying path 32 by turning on / off thereof. For example, the number of rotations of the conveying rollers 35A, 35B, 35C, and 35D after the second front sensor 53 detects the trailing edge of the document is monitored by the number of steps of the encoder and the motor 67, etc. The position of the front end or the rear end is determined.

  The rear sensor 54 disposed immediately upstream of the reading position is for detecting the leading edge and the trailing edge of the document conveyed on the document conveyance path 32 by turning on / off thereof. By monitoring the number of rotations of the transport rollers 35A, 35B, 35C, and 35D after the rear sensor 54 detects the leading edge or trailing edge of the document by the number of steps of the encoder or the motor 67, the leading edge or trailing edge of the document is read. It is determined whether or not the position has been reached. Image reading of the image reading unit 22 is controlled based on a signal from the rear sensor 54. Image reading is started when the leading edge of the document reaches the reading position, and image reading is started when the trailing edge of the document reaches the reading position. Is terminated.

  A switchback sensor 55 disposed between the connection position 38 and the crossing position 40 of the switchback path 39 detects the leading edge or the trailing edge of the document conveyed on the switchback path 39 by turning on / off thereof. belongs to. For example, by monitoring the number of rotations of the transport rollers 35A, 35B, 35C, and 35D and the switchback roller 43 after the switchback sensor 55 detects the trailing edge of the document, the number of steps of the encoder or motor 67 is used to monitor the document. It is determined whether the rear end has passed the crossover position 40 or not.

  FIG. 5 shows a configuration of the control unit 60 of the image reading apparatus 1. The control unit 60 controls not only the ADF 3 but also the entire operation of the image reading apparatus 1. As shown in the figure, the control unit 60 is configured as a microcomputer including a CPU 61, a ROM 62, a RAM 63, and an EEPROM (Electrically Erasable and Programmable ROM) 64, and an ASIC (Application Specific Integrated Circuit) via a bus 65. 66.

  The ROM 62 stores a program for controlling various operations of the image reading apparatus 1 and the ADF 3. The RAM 63 is used as a storage area or a work area for temporarily recording various data used when the CPU 61 executes the program. The EEPROM 64 is a storage area for storing various settings, flags and the like that should be kept even after the power is turned off. These CPU 61, ROM 62, RAM 63, and EEPROM 64 implement the drive control means according to the present invention.

  The ASIC 66 generates a phase excitation signal or the like for energizing the motor 67 in accordance with a command from the CPU 61, applies the signal to the drive circuit 68 of the motor 67, and energizes the motor 67 via the drive circuit 68. Thus, the rotation control of the motor 67 is performed. The motor 67 is rotated in both forward and reverse directions, so that the suction roller 33, the separation roller 34, the transport rollers 35 </ b> A, 35 </ b> B, 35 </ b> C, 35 </ b> D, the paper discharge roller 36, the switchback roller (SB roller) 43, and the guide flap 50. A driving force is applied and the ADF 3 is a single driving source.

  The drive circuit 68 drives the motor 67, receives an output signal from the ASIC 66, and forms an electrical signal for rotating the motor 67. In response to the electrical signal, the motor 67 rotates in a predetermined rotational direction, and the rotational force of the motor 67 is passed through the driving force transmission mechanisms 70, 110, 120, 151, and 170, which will be described later, and the suction roller 33 and the separation roller. 34, the transfer rollers 35 </ b> A, 35 </ b> B, 35 </ b> C, 35 </ b> D, the paper discharge roller 36, the switchback roller 43, and the guide flap 50.

  Connected to the ASIC 66 is an image reading unit 22 that reads an image of a document conveyed to a reading position by the ADF 3. Based on the control program stored in the ROM 62, the image reading unit 22 reads an image of the document. Although not shown in the figure, a drive mechanism for reciprocating the image reading unit 22 is also operated in response to an output signal from the ASIC 66.

  A first front sensor 52, a second front sensor 53, a rear sensor 54, and a switchback sensor 55 are connected to the ASIC 66. The CPU 61 receives ON / OFF of each sensor, and causes the ASIC 66 to output a predetermined output signal based on a control program stored in the ROM 62 to operate the motor 67 and the image reading unit 22.

  A paper feed solenoid 88 and a switchback solenoid (SB solenoid) 161 are connected to the ASIC 66. Based on the control program stored in the ROM 62, the CPU 61 causes the ASIC 66 to output an output signal at a predetermined timing to operate the paper feed solenoid 88 and the switchback solenoid 161.

  Hereinafter, a driving force transmission mechanism from the motor 67 to the suction roller 33, the separation roller 34, the transport rollers 35A, 35B, 35C, and 35D, the paper discharge roller 36, the switchback roller 43, and the guide flap 50 will be described. The axes of the separation roller 34, the conveyance rollers 35A, 35B, 35C, and 35D, the paper discharge roller 36, the switchback roller 43, and the guide flap 50 are in the width direction of the document conveyance path 32 (the vertical direction in FIG. 1, the apparatus depth direction). ). The separation roller 34, the conveyance rollers 35 </ b> A, 35 </ b> B, 35 </ b> C, and 35 </ b> D, the paper discharge roller 36, the switchback roller 43, and the guide flap 50 are provided at predetermined positions on each axis according to the width of the document conveyance path 32. Of course, each roller or the like may be provided over substantially the entire axial direction of each axis, or a plurality of rollers or the like may be coaxially arranged at predetermined intervals in the width direction of the document conveyance path 32.

  As shown in FIG. 6, the ADF 3 provided on the upper surface of the document cover 4 has a document conveyance path 32 and each roller accommodated in a housing. A motor 67 for applying a driving force to each roller and a driving force transmission mechanism are also accommodated in the casing of the ADF 3. The motor 67 and the driving force transmission mechanism are provided on one end side in the width direction of the document conveyance path 32 of the ADF 3. A driven gear is provided on one end side of each shaft of the separation roller 34, the transport rollers 35 </ b> A, 35 </ b> B, 35 </ b> C, 35 </ b> D, the paper discharge roller 36, the switchback roller 43, and the guide flap 50. Each roller is driven by transmitting driving force from the motor 67 to each driven gear via each driving force transmission mechanism. In the present embodiment, the motor 67, each driving force transmission mechanism, the separation roller 34, the transport rollers 35A, 35B, 35C, and 35D, the paper discharge roller 36, the switchback roller 43, and the guide flap 50 are arranged at one end side. Each driven gear provided is accommodated in a space 5 on the back side of the device of the housing of the ADF 3. Each gear shown below is a spur gear in which teeth parallel to the axis are formed on the outer periphery unless otherwise limited.

  7 to 11 show a driving force transmission mechanism 70 (first driving force transmission means) from the motor 67 to the separation roller 34. The driving force transmission mechanism 70 transmits the driving force in the feeding direction to the separation roller 34 by rotating the motor 67 clockwise (CW: clock wise), and counterclockwise (CCW: counter clock wise) from the CW rotation. By switching to rotation, transmission of the driving force to the separation roller 34 is cut off. The CW rotation and the CCW rotation are opposite directions of rotation of the motor 67 and correspond to the forward direction and the reverse direction, respectively.

  As shown in FIG. 7, four transmission gears 71, 72, 73, 74 are sequentially meshed with a drive gear 69 provided on the drive shaft of the motor 67, and the driving force is transmitted to the planetary gear device 75. ing. The transmission gear 74 that directly transmits the driving force to the planetary gear device 75 is the first transmission gear in the present invention, but the four transmission gears 71, 72, 73, 74 are not particularly limited, and the driving gear is not limited. According to the distance from 69 to the planetary gear apparatus 75, it is provided suitably and the number and diameter of a transmission gear are changeable. In response to the CW rotation or CCW rotation of the motor 67, the sequentially engaged transmission gears 71, 72, 73 rotate in a predetermined direction, and the driving force is transmitted so that the transmission gear 74 rotates CCW or CW.

  FIG. 9 shows the configuration of the planetary gear device 75. In the planetary gear device 75, a support arm 78 is rotatably provided coaxially with the shaft 77 of the sun gear 76, and two planetary gears 79 (first planetary gears) that respectively mesh with the sun gear 76 on the support arm 78. The planetary gear 80 (second planetary gear) is pivotally supported.

  The sun gear 76 is a two-stage gear in which a large-diameter gear 76L and a small-diameter gear 76S are coaxially and integrally configured. The support arm 78 has arm portions 81 and 82 extending in two radial directions from the shaft 77, and the planetary gears 79 and 80 are respectively shafted by bearing portions 83 and 84 formed at the tips of the arm portions 81 and 82. It is something to support. The planetary gears 79 and 80 supported by the support arm 78 are engaged with the gear 76S of the sun gear 76, respectively. When the sun gear 76 rotates, the planetary gears 79 and 80 respectively meshed with the gear 76S rotate. Further, the support arm 78 also rotates in the same direction in response to the rotation of the sun gear 76. That is, when the sun gear 76 rotates, the planetary gears 79 and 80 revolve around the sun gear 76 while rotating respectively.

  A locking recess 85 is formed in the vicinity of the shaft 77 of the support arm 78. When the locking recess 85 is locked by the locking mechanism 86, the support arm 78 is stopped at a predetermined position regardless of the rotation of the sun gear 76. The posture in which the support arm 78 is locked to the locking mechanism 86 is a disengagement posture described later.

  The locking mechanism 86 includes a locking member 87 and a paper feed solenoid 88. The locking member 87 includes an arm portion 90 extending in a radial direction from the shaft 89 toward the support arm 78, a locking claw 91 formed in a hook shape at the tip of the arm portion 90, and a radial direction from the shaft 89. And a passive portion 92 extending to the center. The locking claw 91 can be engaged with the locking recess 85 of the support arm 78, and is engaged with and disengaged from the locking recess 85 when the arm portion 90 is rotated about the shaft 89. The passive unit 92 is connected to the shaft 93 of the paper feed solenoid 89. The sheet feeding solenoid 89 is actuated by electromagnetic force when electric power is supplied (turned on), linearly drives the shaft 93 in the direction of immersing the main body in the main body, and is cut off (off) by electromagnetic force. Disappears, and the shaft 93 is elastically returned in the direction of protruding from the main body. The drive of the shaft 93 is transmitted to the passive portion 92, and the locking member 87 is rotated about the shaft 89 to assume a predetermined posture. With the sheet feed solenoid 89 turned off, the locking member 87 is in a posture in which the locking claw 91 can engage with the locking recess 85 of the support arm 78 as shown by a solid line in FIG. With the sheet feeding solenoid 89 turned on, the locking member 87 is in a posture to disengage the locking claw 91 from the locking recess 85 as indicated by a two-dot chain line in FIG.

  As shown in FIG. 7, the transmission gear 74 meshes with the gear 76 </ b> L of the sun gear 76 of the planetary gear device 75. When the driving force is transmitted from the motor 67 and the transmission gear 74 rotates in a predetermined direction, the sun gear 76 is rotated in a predetermined direction. For example, as shown in FIG. 7, when the drive gear 69 rotates CW, the transmission gear 74 rotates CW and the sun gear 76 rotates CCW. Since the support arm 78 is rotatable when the paper feed solenoid 89 is on, the planetary gears 79 and 80 revolve by CW rotation. The paper feed solenoid 89 only needs to be turned on when the latching claw 91 is detached from the latching recess 85. Even if the paper feed solenoid 89 is turned off after the support arm 78 rotates from the detached posture, The locking claw 91 does not engage with the locking recess 85.

  As shown in FIG. 8, a transmission gear 94 is disposed adjacent to the planetary gear device 75. The transmission gear 94 can be separated from the planetary gears 79 and 80 of the planetary gear device 75. As shown in the figure, the planetary gears 79 and 80 revolve around the CCW rotation, whereby the planetary gear 79 meshes with the transmission gear 94 and the planetary gear 80 moves away from the transmission gear 94. The transmission gear 94 is a two-stage gear in which a large-diameter gear 94L and a small-diameter gear 94S are coaxially and integrally configured. The planetary gears 79 and 80 can be engaged with and separated from the large-diameter gear 94L. The small-diameter gear 94S meshes with a driven gear 95 provided on a shaft 111 (see FIG. 12) that supports the separation roller 34. The transmission gear 94 to which the driving force is directly transmitted from the planetary gear device 75 is the second transmission gear in the present invention, but the gear configuration from the transmission gear 94 to the driven gear 95 is not particularly limited, and the transmission gear is not limited. Depending on the distance from 94 to the driven gear 95, the number and diameter of the transmission gears can be changed as appropriate.

  When the planetary gear 79 revolved by the CCW rotation meshes with the transmission gear 94, the revolution of the planetary gear 79 is stopped. Then, the planetary gear 79 rotates by the CW rotation upon receiving the driving force transmitted from the sun gear 76. In response to this, the transmission gear 94 rotates CCW, and the driven gear 95 rotates CW. As the driven gear 95 rotates CW, the shaft 111 that supports the separation roller 34 is rotated in the paper feeding direction.

  As shown in FIG. 10, when the drive gear 69 is switched from CW rotation to CCW rotation, the transmission gear 74 rotates CCW and the sun gear 76 rotates CW. As shown in FIG. 8, in a state where the planetary gear 79 is engaged with the transmission gear 94, the locking claw 91 does not engage with the locking recess 85 even if the paper feed solenoid 89 is off. Therefore, since the support arm 78 is rotatable, the planetary gears 79 and 80 revolve by CW rotation. As the planetary gears 79 and 80 revolve, the support arm 78 rotates, so that the locking recess 85 of the support arm 85 can be engaged with the locking claw 91. At this time, if the paper feed solenoid 89 is off, the locking claw 91 engages with the locking recess 85 as shown in FIG. 10, and the rotation of the support arm 78 is restricted. In this state, both the planetary gears 79 and 80 are not meshed with the transmission gear 94. The posture of the support arm 78 so that both the planetary gears 79 and 80 are separated from the transmission gear 94 is the separation posture in the present invention. When the locking claw 91 is engaged with the locking recess 85, the support arm 78 is locked in a non-rotatable manner, and then the support arm 78 is held in the disengaged posture until the paper feed solenoid 89 is turned on. The

  As shown in FIG. 11, when the paper feed solenoid 89 is turned on, the planetary gears 79 and 80 revolve around the CW rotation based on the CW rotation of the sun gear 76. When the planetary gear 80 revolved by the CW rotation meshes with the transmission gear 94, the revolution of the planetary gear 80 is stopped. Then, the planetary gear 80 rotates by CCW rotation upon receiving the driving force transmitted from the sun gear 76. In response to this, the transmission gear 94 rotates CW and the driven gear 95 rotates CCW. As the driven gear 95 rotates CCW, the shaft 111 that supports the separation roller 34 is rotated in the direction opposite to the paper feeding direction.

  Hereinafter, the driving force transmission mechanism 110 from the shaft 111 that supports the separation roller 34 to the suction roller 33 will be described. As shown in FIG. 1, the suction roller 33 is pivotally supported on the distal end side of the arm 29 and is arranged on the opposite side of the separation roller 34 in the feeding direction. As described above, the driving force of the motor 67 is transmitted to the shaft 111, and the driving force is transmitted from the shaft 111 to the arm 29, the suction roller 33 and the separation roller 34.

  FIG. 12 shows the driving force transmission mechanism 110 from the shaft 111 to the suction roller 33. The driving force transmission mechanism 110 includes a one-round clutch 112 provided on a shaft 111, a gear 113 integrally formed with the separation roller 34, a gear 115 fixed to the shaft 114 of the suction roller 33, and a gear 113 to a gear. And a transmission gear 116 for transmitting driving force to 115. The separation roller 34 is rotatably supported on the shaft 111. The one-round clutch 112 and the gear 113 are provided on both sides in the axial direction of the separation roller 34. In FIG. 12, the one-round clutch 112 is provided on the back side of the separation roller 34 in the figure, and the front side is illustrated. A gear 113 is provided, and the one-round clutch 112 on the back side of the separation roller 34 is indicated by a dotted line.

  The one-round clutch 112 includes a pin 117 protruding in the radial direction from the shaft 111 and a locking piece 118 protruding in the axial direction from the separation roller 34. The pin 117 protrudes in the radial direction of the shaft 111 on the side of the separation roller 34, and rotates with the rotation of the shaft 111. The locking piece 118 protrudes in the axial direction from the side surface of the separation roller 34. The position of the locking piece 118 with respect to the radial direction of the separation roller 34 is within the range of the protruding length of the pin 117, and the pin 117 and the locking piece 118 can be engaged. As shown in the figure, when the pin 117 is engaged with the locking piece 118, the rotation of the shaft 111 is transmitted to the separation roller 34 via the pin 117 and the locking piece 118, and the separation roller 34 is connected to the shaft 111. It is rotated in the same direction.

  Since the separation roller 34 is rotatable with respect to the shaft 111, the separation roller 34 is rotatable in a direction in which the locking piece 118 is separated from the pin 117. Then, when the separation roller 34 rotates about one turn with respect to the shaft 111, the locking piece 118 reaches the position of the pin 117 again and engages. As a result, the separation roller 34 can rotate idly for approximately one round regardless of the transmission of the driving force from the shaft 111.

  A transmission gear 116 is interposed between the gear 113 provided on the separation roller 34 and the gear 115 fixed to the shaft 114 of the suction roller 33. The transmission gear 116 meshes with the gear 113 and the gear 115. Since the gear 113 is integral with the separation roller 34, the gear 113 is rotated as the separation roller 34 rotates. The transmission gear 116 is rotated by the rotation of the gear 113, and the gear 115 is rotated by the rotation of the transmission gear 116. Since the gear 115 is fixed to the shaft 114 of the suction roller 33, the suction roller 33 is rotated with the rotation of the gear 115. That is, the separation roller 34 and the suction roller 33 are always rotated in the same direction. By such a driving force transmission mechanism 110, the driving force is transmitted from the shaft 111 that rotatably supports the separation roller 34 to the separation roller 34 and the suction roller 22.

  As shown in FIG. 12, the base end side of the arm 29 is rotatably supported by a shaft 111, and the driving force is transmitted from the shaft 111 and is swung. A slip clutch (not shown) is provided between the shaft 111 and the base end side of the arm 29. The rotation of the shaft 111 is transmitted to the arm 29 by the slip clutch. In the slip clutch, when a load of a predetermined torque or more is applied, the clutch plate slips and driving force transmission is cut off. When the shaft 111 rotates CW, a rotational force is transmitted to the arm 29 via the slip clutch, and the arm 29 rotates in a direction in which the suction roller 33 is lowered. On the other hand, if the shaft 111 rotates in the CCW direction, the arm 29 rotates in a direction in which the suction roller 33 is raised. As shown in FIG. 1, when the arm 29 rotates in the direction of lowering the suction roller 33, the suction roller 33 comes into contact with the document placement surface of the document conveyance path 32 or the document on the paper feed tray 30. As a result, a load is generated with respect to the rotation of the arm 29, the slip clutch slides, and the shaft 111 can further rotate in a state where the arm 29 is stationary. If the arm 29 rotates in a direction to raise the suction roller 33, the arm 29 comes into contact with the casing of the ADF 3. As a result, a load is generated with respect to the rotation of the arm 29, the slip clutch slides, and the shaft 111 can further rotate in a state where the arm 29 is stationary. In this way, the driving force is transmitted from the shaft 111 to the arm 29 via the slip clutch, and the arm 29 is swung so as to bring the suction roller 33 into and out of contact with the document placement surface of the document conveyance path 32. .

  13 to 15 show the driving force transmission mechanism 120 (second driving force transmission means) from the motor 67 to the transport rollers 35A, 35B, 35C, and 35D. The driving force transmission mechanism 120 transmits a driving force from the upstream side to the downstream side of the document conveyance path 32 to the conveyance rollers 35A, 35B, 35C, and 35D regardless of the rotation direction of the motor 67. .

  As shown in FIG. 13, a transmission gear 121 is meshed with a drive gear 69 provided on the drive shaft of the motor 67, and the driving force is transmitted to the planetary gear device 122. In response to the CW rotation or CCW rotation of the motor 67, the driving force is transmitted so that the transmission gear 121 rotates CCW or CW. The number of gears from the drive gear 69 to the transmission gear 121 is not particularly limited, and the number and diameter of the transmission gears can be changed according to the distance from the drive gear 69 to the planetary gear device 122.

  In the planetary gear device 122, a support arm 125 is rotatably provided coaxially with the shaft 124 of the sun gear 123, and two planetary gears 126 and a planetary gear 127 respectively meshing with the sun gear 123 are pivotally supported on the support arm 125. Being done.

  The sun gear 123 is a two-stage gear in which a large-diameter gear 123L and a small-diameter gear 123S are coaxially and integrally configured. The planetary gears 126 and 127 pivotally supported by the support arm 125 mesh with the gear 123S of the sun gear 123, respectively. When the sun gear 123 rotates, the planetary gears 126 and 127 respectively meshed with the gear 123S rotate. Further, the support arm 125 also rotates in the same direction in response to the rotation of the sun gear 123. That is, when the sun gear 123 rotates, the planetary gears 126 and 127 revolve around the sun gear 123 while rotating respectively.

  The transmission gear 121 meshes with the sun gear 123 of the planetary gear device 122. When the driving force is transmitted from the motor 67 and the transmission gear 121 rotates in a predetermined direction, the sun gear 123 is rotated in the predetermined direction. For example, as shown in FIG. 13, when the drive gear 69 rotates CCW, the transmission gear 121 rotates CW, the sun gear 123 rotates CCW, and the planetary gears 126 and 127 revolve around CCW rotation.

  As shown in the figure, a transmission gear 128 and a transmission gear 129 are disposed adjacent to the planetary gear device 122. The transmission gear 128 is a two-stage gear in which a large-diameter gear 128L and a small-diameter gear 128S are coaxially and integrally configured. Similarly, the transmission gear 129 is a two-stage gear in which a large-diameter gear 129L and a small-diameter gear 129S are coaxially and integrally configured. The planetary gear 126 of the planetary gear device 122 can be engaged with and disengaged from the gear 128 </ b> L of the transmission gear 128. The planetary gear 127 of the planetary gear device 122 can be separated from the gear 129L of the transmission gear 129. Further, the gear 128L and the gear 129L are meshed with each other.

  As shown in FIG. 13, the planetary gears 126 and 127 revolve around the CCW rotation, so that the planetary gear 126 meshes with the gear 128 </ b> L of the transmission gear 128. On the other hand, the planetary gear 127 is detached from the transmission gear 129. When the planetary gear 126 revolved by the CCW rotation meshes with the transmission gear 128, the revolution of the planetary gears 126 and 127 is stopped. Then, the planetary gear 126 rotates by the CW rotation upon receiving the driving force transmitted from the sun gear 123. In response to this, the transmission gear 128 rotates CCW. The transmission gear 129 that meshes with the transmission gear 128 rotates CW.

  As shown in FIG. 14, when the drive gear 69 rotates CW, the transmission gear 121 rotates CCW, the sun gear 123 rotates CW, and the planetary gears 126 and 127 revolve around CW rotation. As the planetary gears 126 and 127 revolve by CW rotation, the planetary gear 127 meshes with the gear 129L of the transmission gear 129. On the other hand, the planetary gear 126 is separated from the transmission gear 128. When the planetary gear 127 revolved by the CW rotation is engaged with the transmission gear 129, the revolution of the planetary gears 126 and 127 is stopped. Then, the planetary gear 127 rotates by CCW rotation upon receiving the driving force from the sun gear 123. In response to this, the transmission gear 129 rotates CW. The transmission gear 128 that meshes with the transmission gear 129 rotates CCW. In this way, regardless of whether the drive gear 69 is CW rotation or CCW rotation, the transmission gear 128 is transmitted with the CCW rotation driving force, and the transmission gear 129 is transmitted with the CW rotation driving force. .

  FIG. 15 shows transmission of driving force from the transmission gears 128 and 129 to the respective transport rollers 35A, 35B, 35C, and 35D and the paper discharge roller 36. Five transmission gears 130, 131, 132, 133, and 134 are sequentially meshed with the gear 128S of the transmission gear 128. The transmission gear 133 is engaged with a driven gear 135 provided on the shaft of the conveying roller 35A, and the transmission gear 124 is engaged with a driven gear 136 provided on the shaft of the paper discharge roller 36. As described above, the transmission gear 128 is CCW rotated regardless of the rotation direction of the drive gear 69, and the driving force is sequentially transmitted from the transmission gear 128 to the five transmission gears 130, 131, 132, 133, and 134. In response, the driven gear 135 rotates CW and the driven gear 136 rotates CCW. As the driven gear 125 rotates CW, the transport roller 35A is rotated in the transport direction. Further, as the driven gear 126 rotates in the CCW direction, the paper discharge roller 36 is rotated in the transport direction.

  Three transmission gears 137, 138, and 139 are sequentially meshed with the gear 129S of the transmission gear 129. Then, the driven gear 140 provided on the shaft of the conveying roller 35D is engaged with the gear 129S, the driven gear 141 provided on the shaft of the conveying roller 35C is engaged with the transmission gear 138, and the conveying roller 139 is engaged with the conveying roller 139. A driven gear 142 provided on the shaft of 35B is meshed. As described above, the transmission gear 129 is CW-rotated regardless of the rotation direction of the drive gear 69, and the driving force is sequentially transmitted from the transmission gear 129 to the three transmission gears 137, 138, and 139. In response to this, the driven gears 140 and 141 rotate CCW and the driven gear 142 rotates CW. As the driven gears 140 and 141 rotate CCW, the transport rollers 35D and 35C are rotated in the transport direction. As the driven gear 142 rotates CW, the transport roller 35B is rotated in the transport direction. In this way, the driving force in the transport direction is transmitted to the transport rollers 35A, 35B, 35C, and 35D and the paper discharge roller 36 in the rotational direction of the drive gear 69.

  Note that the gear configuration from the transmission gears 128 and 129 to the driven gears 135, 136, 140, 141, and 142 is not particularly limited, and the transmission gears are arranged according to the distances from the transmission gears to the driven gears. The number and diameter can be changed as appropriate.

  FIGS. 16 to 18 show a driving force transmission mechanism 150 (third driving force transmission means) and a driving force cutting mechanism 151 (driving force cutting means) from the motor 67 to the switchback roller 43. The driving force transmission mechanism 150 transmits the driving force in the retracting direction or the returning direction to the switchback roller 43 based on the rotation direction of the motor 67. The driving force cutting mechanism 151 cuts the transmission of the driving force from the motor 67 to the switchback roller 43 when the rotation direction of the motor 67 is switched from the return direction of the switchback roller 43 to the pulling direction. The pull-in direction is a direction in which a document is drawn from the document conveyance path 32 to the switchback path 39, and the return direction is a direction in which the document is returned from the switchback path 39 to the document conveyance path 32.

  As shown in FIG. 16, the transmission gear 152 is engaged with a drive gear 69 provided on the drive shaft of the motor 67, and the drive force is transmitted to the planetary gear device 153. In response to the CW rotation or CCW rotation of the motor 67, the driving force is transmitted so that the transmission gear 152 rotates CCW or CW. The configuration from drive gear 69 to transmission gear 152 is not particularly limited, and the number and diameter of the transmission gears can be changed according to the distance from drive gear 69 to planetary gear device 153.

  In the planetary gear device 153, a support arm 156 is rotatably provided coaxially with the shaft 155 of the sun gear 154, and two planet gears 157 and a planet gear 158 that mesh with the sun gear 154 are supported on the support arm 156, respectively. Being done.

  The sun gear 154 is a two-stage gear in which a large-diameter gear 154L and a small-diameter gear 154S are coaxially and integrally configured. The support arm 156 is rotatably provided on the shaft 155 and supports the planetary gears 157 and 158 respectively. The planetary gears 157 and 158 that are pivotally supported by the support arm 156 mesh with the gear 154S of the sun gear 154, respectively. When the sun gear 154 rotates, the planetary gears 157 and 158 respectively engaged with the gear 154S rotate. Further, the support arm 156 rotates in the same direction in response to the rotation of the sun gear 154. That is, when the sun gear 154 rotates, the planetary gears 157 and 158 revolve around the sun gear 154 while rotating respectively.

  A locking projection 159 is formed near the tip where the support arm 156 pivotally supports the planetary gear 157. When the locking projection 159 is locked to the driving force cutting mechanism 151, the support arm 156 that rotates CCW relative to the shaft 155 of the sun gear 154 is stopped at a predetermined position. As shown in FIG. 16, the posture in which the support arm 156 is locked to the driving force cutting mechanism 151 is a disengagement posture described later.

  The driving force cutting mechanism 151 includes a locking member 160 and a switchback solenoid 161. The locking member 160 includes an arm portion 163 extending in a radial direction from the shaft 162 toward the support arm 156, a locking claw 164 formed in a hook shape at the tip of the arm portion 163, and a radial direction from the shaft 162. And a passive portion 165 extending to the center. The locking claw 164 can be engaged with the locking projection 159 of the support arm 156, and is engaged with and disengaged from the locking projection 159 when the arm portion 163 is rotated about the shaft 162. The passive portion 165 is connected to the shaft 166 of the switchback solenoid 161. The switchback solenoid 161 is actuated by electromagnetic force when electric power is supplied (turned on), linearly drives the shaft 166 in a direction to be immersed in the main body, and is cut off (off) by electromagnetic force. Disappears, and the shaft 166 is elastically restored linearly in a direction in which the shaft 166 protrudes from the main body. The driving of the shaft 166 is transmitted to the passive portion 165, and the locking member 160 is rotated about the shaft 162 to assume a predetermined posture.

  With the switchback solenoid 161 turned off, the locking member 160 is in a posture in which the locking claw 164 can engage with the locking projection 159 of the support arm 156 as shown by the solid line in FIG. The locking member 160 can rotate clockwise from this engagement posture, and is biased by a spring or the like to maintain the engagement posture unless receiving external force. The locking projection 159 rotates with the rotation of the support arm 156, and the rotation direction is a substantially radial direction of the locking member 160 in the engagement posture. Therefore, even if the rotational force of the support arm 156 is transmitted to the locking member 160 via the locking projection 159, the locking member 160 does not rotate from the engagement posture against the urging force of a spring or the like. With the switchback solenoid 161 turned on, the locking member 160 is in a posture to release the locking claw 164 from the locking projection 159 as shown by a two-dot chain line in FIG.

  As shown in FIG. 16, the transmission gear 152 meshes with the gear 154 </ b> L of the sun gear 154 of the planetary gear device 153. When the driving force is transmitted from the motor 67 and the transmission gear 152 rotates in a predetermined direction, the sun gear 154 is rotated in a predetermined direction. For example, as shown in FIG. 16, when the drive gear 69 rotates CCW, the transmission gear 152 rotates CW and the sun gear 154 rotates CCW. In response to this, the planetary gears 157 and 158 revolve by CCW rotation. As the planetary gears 157 and 158 revolve, the support arm 156 rotates, so that the locking convex portion 159 of the support arm 156 can be engaged with the locking claw 164. At this time, if the switchback solenoid 161 is off, the locking claw 164 engages with the locking projection 159 and the rotation of the support arm 156 is restricted as shown in FIG. In this state, both the planetary gears 157 and 158 are not meshed with the transmission gear 167. The posture of the support arm 156 so that both the planetary gears 157 and 158 are separated from the transmission gear 167 is the separation posture in the present invention. By engaging the locking claw 164 with the locking projection 159, the CCW rotation of the support arm 156 is restricted until the switchback solenoid 161 is turned on, and the support arm 156 is held in the detached posture. .

  As shown in FIG. 16, the transmission gear 167 is disposed at a position adjacent to the planetary gear device 153. The transmission gear 167 can be separated from the planetary gears 157 and 158 of the planetary gear device 153. The transmission gear 167 is a two-stage gear in which a large-diameter gear 167L and a small-diameter gear 167S are coaxially and integrally configured. The planetary gears 157 and 158 can be engaged with and disengaged from the large-diameter gear 167L. The small-diameter gear 167S meshes with a driven gear 168 provided on the shaft of the switchback roller 43. Note that the gear configuration from the transmission gear 167 to the driven gear 168 is not particularly limited, and the number and diameter of the transmission gears can be appropriately changed according to the distance from the transmission gear 167 to the driven gear 168.

  As shown in FIG. 17, when the drive gear 69 rotates CW, the transmission gear 152 rotates CCW and the sun gear 154 rotates CW. In response to this, the planetary gears 157 and 158 revolve by CW rotation. As the planetary gears 157 and 158 revolve, the support arm 156 rotates. When the support arm 156 rotates CW, the locking projection 159 moves away from the locking claw 164. Therefore, even if the switchback solenoid 161 is off, the support arm 159 can perform CW rotation. As the planetary gears 157 and 158 revolve by CW rotation, the planetary gear 157 meshes with the transmission gear 167.

  When the planetary gear 157 revolved by the CW rotation meshes with the transmission gear 167, the revolution of the planetary gear 157 is stopped. And the planetary gear 157 rotates by CCW rotation in response to transmission of driving force from the sun gear 154. In response to this, the transmission gear 167 rotates CW and the driven gear 168 rotates CCW. As the driven gear 168 rotates CCW, the switchback roller 43 is rotated in the return direction.

  When the switchback solenoid 161 is turned on from the state shown in FIG. 16, the locking member 160 is rotated and the locking claw 164 is detached from the locking projection 159. Accordingly, the support arm 156 can perform CCW rotation, and the planetary gears 157 and 158 revolve by CCW rotation. As shown in FIG. 18, the planetary gear 158 revolved by CCW rotation meshes with the transmission gear 167, whereby the revolution of the planetary gear 158 is stopped. Then, the planetary gear 158 rotates by CW rotation upon receiving the driving force transmitted from the sun gear 154. In response to this, the transmission gear 167 rotates CCW, and the driven gear 168 rotates CW. As the driven gear 168 rotates in the CW direction, the switchback roller 43 is rotated in the retracting direction. The switchback solenoid 161 may be turned on only when the latching claw 164 is detached from the latching projection 159, and the switchback solenoid 161 is turned off after the support arm 156 rotates CCW from the detached posture. However, the locking claw 164 does not engage with the locking projection 159.

  By switching the rotation of the drive gear 67 from CCW rotation to CW rotation, the support arm 156 can perform CW rotation from the state shown in FIG. 18 where the planetary gear 158 and the transmission gear 167 are engaged. When the support arm 156 rotates CW, the planet gear 157 and the transmission gear 167 are engaged with each other as shown in FIG. Then, when the rotation of the drive gear 67 is switched from the CW rotation to the CCW rotation, the support arm 156 rotates CCW from the state shown in FIG. 17, and the locking claw 164 and the locking projection 159 as shown in FIG. The disengagement posture is engaged.

  19 and 20 show a driving force transmission mechanism 170 (fourth driving force transmission means) from the motor 67 to the guide flap 50. The driving force transmission mechanism 140 changes the posture of the guide flap 50 to the first guide posture or the second guide posture based on the rotation direction of the motor 67.

  As shown in FIG. 19, transmission gears 171, 172, and 173 are sequentially meshed with a driving gear 69 provided on the driving shaft of the motor 67, and the driving force is transmitted from the transmission gear 173 to the planetary gear device 174. ing. Upon receiving the CW rotation or CCW rotation of the motor 67, the driving force is transmitted so that the transmission gear 173 rotates CCW or CW. The number of gears from the drive gear 69 to the transmission gear 173 is not particularly limited, and the number and diameter of the transmission gears can be changed according to the distance from the drive gear 69 to the planetary gear device 174.

  In the planetary gear device 174, a support arm 177 is rotatably provided coaxially with the shaft 176 of the sun gear 175, and two planet gears 178 and a planet gear 179 that respectively mesh with the sun gear 175 are supported on the support arm 177. Being done.

  The sun gear 175 is a two-stage gear in which a large-diameter gear 175L and a small-diameter gear 175S are coaxially and integrally configured. The planetary gears 178 and 179 supported by the support arm 177 mesh with the gear 175S of the sun gear 175, respectively. When the sun gear 175 rotates, the planetary gears 178 and 179 respectively engaged with the gear 175S rotate. Further, the support arm 177 rotates in the same direction in response to the rotation of the sun gear 175. That is, when the sun gear 175 rotates, the planetary gears 178 and 179 revolve around the sun gear 175 while rotating respectively.

  The transmission gear 173 meshes with the sun gear 175 of the planetary gear device 174. When the driving force is transmitted from the motor 67 and the transmission gear 173 rotates in a predetermined direction, the sun gear 175 is rotated in the predetermined direction. For example, as shown in FIG. 19, when the drive gear 69 rotates CW, the transmission gear 173 rotates CCW, the sun gear 175 rotates CW, and the planetary gears 178 and 179 revolve with CW rotation.

  As shown in the figure, a transmission gear 180 and a transmission gear 181 are arranged adjacent to the planetary gear device 174. The transmission gear 180 is a two-stage gear in which a large-diameter gear 180L and a small-diameter gear 180S are coaxially and integrally configured. The planetary gears 178 and 179 of the planetary gear device 174 can be engaged with and disengaged from the gear 180L of the transmission gear 180. Further, the gear 180 </ b> S of the transmission gear 180 and the transmission gear 181 are meshed, and the transmission gear 181 is meshed with a driven gear 182 provided on the shaft of the guide flap 50.

  As shown in FIG. 19, the planetary gears 178 and 179 revolve by CW rotation, whereby the planetary gear 178 meshes with the gear 180 </ b> L of the transmission gear 180. On the other hand, the planetary gear 179 is detached from the transmission gear 180. When the planetary gear 178 revolved by the CW rotation is engaged with the transmission gear 180, the revolution of the planetary gears 178 and 179 is stopped. Then, the planetary gear 178 rotates by CCW rotation upon receiving the driving force transmitted from the sun gear 175. In response to this, the transmission gear 180 rotates CW. The transmission gear 181 meshing with the transmission gear 180 rotates CCW, and the driven gear 182 meshing with the transmission gear 181 rotates CW. By the CW rotation of the driven gear 182, the guide flap 50 is rotated so as to swing upward and assumes the first guiding posture.

  As shown in FIG. 20, when the drive gear 69 rotates CCW, the transmission gear 173 rotates CW, the sun gear 175 rotates CCW, and the planetary gears 178 and 179 revolve with CCW rotation. As the planetary gears 178 and 179 revolve by CCW rotation, the planetary gear 179 meshes with the gear 180L of the transmission gear 180. On the other hand, the planetary gear 178 is detached from the transmission gear 180. When the planetary gear 179 revolved by CCW rotation meshes with the transmission gear 180, the revolution of the planetary gears 178 and 179 is stopped. Then, the planetary gear 179 receives the driving force transmitted from the sun gear 175 and rotates by CW rotation. In response to this, the transmission gear 180 rotates CCW. The transmission gear 181 meshing with the transmission gear 180 rotates CW, and the driven gear 182 meshing with the transmission gear 181 rotates CCW. As the driven gear 182 rotates CCW, the guide flap 50 is rotated so as to swing downward and assumes the second guiding posture.

  Although not shown in the figure, a slip clutch is provided between the shaft provided with the driven gear 182 and the guide flap 50. The rotation of the shaft is transmitted to the guide flap 50 by the slip clutch. In the slip clutch, when a load of a predetermined torque or more is applied, the clutch plate slips and the driving force transmission is cut off. As shown in FIG. 3, the guide flap 50 is swung between the first guide posture and the second guide posture, and rotates beyond each posture by contacting the guide member or the like. It is regulated not to be moved. Therefore, after the guide flap 50 is in the first guide posture or the second guide posture, the rotation of the guide flap 50 is restricted so that the slip clutch slips and the guide flap 50 is moved to the first guide posture or The shaft provided with the driven gear 182 can be further rotated in a state of being stationary in the second guiding posture. The gear configuration from the transmission gear 180 to the driven gear 182 is not particularly limited, and the number and diameter of the transmission gears can be appropriately changed according to the distance from the transmission gear 180 to each driven gear 182.

Hereinafter, an image reading operation by the image reading apparatus 1 will be described.
The image reading apparatus 1 can be used as an FBS or an ADF 3, but the use of the FBS is not particularly related to the present invention, and a detailed description thereof will be omitted. When the ADF 3 is used, the document cover 4 is closed with respect to the document table 2. Opening / closing of the document cover 4 is detected by a sensor or the like provided on the document table 2 and is controlled so that the ADF 3 can be used when the document cover 4 is closed. Then, the document Gn to be read is placed on the paper feed tray 30. The original Gn is placed on the paper feed tray 30 so-called face-up so that the reading surface (first surface) is on the upper side. Further, the document Gn may be one sheet or a plurality of sheets. For example, when reading images of a plurality of documents Gn of the same size, the first document G1 is placed on the sheet feed tray 30 so that the first surface of the first document G1 faces upward, that is, face up. Placed.

  When reading start is input to the image reading apparatus 1, the motor 67 is driven, and the suction roller 33, the separation roller 34, the transport rollers 35A, 35B, 35C, and 35D, the paper discharge roller 36, and the switchback roller 43 are predetermined. It is rotationally driven at the timing. Further, the arm 29 is lowered, and the suction roller 33 comes into pressure contact with the original G1 on the paper feed tray 30. Then, the sheets are separated one by one from the uppermost document G 1 that directly receives the rotational force of the suction roller 33 and the separation roller 34, and sent to the document conveyance path 32. The fed document Gn is guided to the document conveyance path 32 and conveyed to the reading position, and the image reading unit 22 stationary below the reading position reads the image of the document Gn. Then, the document Gn after the image reading is discharged to the paper discharge tray 31. In such an image reading operation, the conveyance path of the original Gn differs depending on whether single-sided reading of the original Gn is performed or double-sided reading. Whether to perform single-sided reading or double-sided reading of the original Gn is determined by a preset single-sided reading mode (single-sided reading conveyance mode) or double-sided reading mode (double-sided reading conveyance mode) before inputting the reading start. Is done.

  FIG. 21 is a timing chart showing the operation of the image reading apparatus 1 in the single-sided reading mode. Before the start of reading, as shown in FIG. 22, the guide flap 50 is in a position where the conveyance path at the connection position 38 is continuous from the reading position side of the document conveyance path 32 to the discharge tray 31 side. In a state where the document Gn is not in contact, the guide flap 46 is in a third guiding posture, that is, a position where the conveyance path at the crossing position 40 is continued from the paper feed tray 30 side of the document conveyance path 32 to the reading position side. In a state where the document Gn is not in contact, the guide flap 47 is in a fifth guiding posture, that is, a position where the conveyance path at the crossing position 40 is continued from the terminal end 41 side of the switchback path 39 to the reading position side of the document conveyance path 32. It is in.

  When reading start is input to the image reading apparatus 1, the first front sensor 52 detects whether or not the document Gn is placed on the paper feed tray 30. When the control unit 60 determines that the document Gn is not placed on the paper feed tray 30, the control unit 60 displays an error message “No Document” on the display unit of the image reading apparatus 1. If the document Gn is placed on the paper feed tray 30, the motor 67 is driven by CW rotation. In the present embodiment, it is assumed that the motor 67 rotates CW at the start of reading. However, whether the motor 67 is rotated CW or CCW at the start of reading is arbitrary, and the rotation direction of the motor 67 is relative. Concept.

  The controller 60 drives the motor 67 by CW rotation and turns on the paper feed solenoid 88. As a result, as shown in FIGS. 7 and 8, the planetary gear device 75 of the driving force transmission mechanism 70 is unlocked by the locking mechanism 86, and the planetary gears 79, 80 are based on the rotation of the sun gear 76. Is revolved by CCW rotation to transmit the driving force to the transmission gear 94. As a result, the driven gear 95 rotates CW. As the driven gear 95 rotates CW, the driving force is transmitted to the arm 29 and the arm 29 is lowered. As a result, the suction roller 33 comes into pressure contact with the document G1 on the paper feed tray 30. In addition, the CW rotation of the driven gear 95 is transmitted to the suction roller 33 and the separation roller 34 by the driving force transmission mechanism 110, and the suction roller 33 and the separation roller 34 rotate in the feeding direction, whereby the document G1 is fed to the document conveyance path 32. It is carried to. When a plurality of documents Gn are placed on the sheet feed tray 30, the document G2 directly below the document G2 may be double-fed along with the document G1 at the uppermost position. It is restrained by the separation pad provided at the facing position.

  In the document conveyance path 32, the driving force from the motor 67 is transmitted to the conveyance rollers 35 </ b> A, 35 </ b> B, 35 </ b> C, 35 </ b> D and the paper discharge roller 36 by the driving force transmission mechanism 120, and each roller is downstream from the upstream side of the document conveyance path 32. The original Gn is conveyed to the side, that is, rotated in the conveyance direction. The document G1 fed from the sheet feed tray 30 to the document transport path 32 is nipped by the transport roller 35A and the pinch roller 37 and is transmitted with a rotational force, so that the document G1 is transported to the intersection position 40 through the document transport path 32. . The second front sensor 53 is turned on when the document G1 is fed to the document transport path 32.

  Since the guide flap 47 closes the conveyance path from the paper feed tray 30 side of the document conveyance path 32 to the intersection position 40, the document G 1 conveyed to the intersection position 40 abuts on the guide flap 47. As shown in FIG. 23, the guide flap 47 changes its posture from the fifth guide posture to the sixth guide posture so as to be pushed by the document G1 conveyed through the document conveyance path 32. As a result, the conveyance path from the paper feed tray 30 side to the reading position side of the document conveyance path 32 continues and the conveyance path to the terminal end 41 side of the switchback path 39 is closed. In addition, the conveyance path to the connection position 38 side of the switchback path 39 is closed by the guide flap 46. Therefore, the document G1 that has reached the crossing position 40 from the paper feed tray 30 side of the document transport path 32 is guided by the guide flap 46 and the guide flap 47, and does not enter any direction of the switchback path 39. The document is conveyed to the reading position side of the document conveyance path 32.

  The peripheral speeds of the transport rollers 35A, 35B, 35C, 35D and the paper discharge roller 36, which are rotated by the driving force transmitted from the motor 67 by the driving force transmitting mechanism 120, are driven by the driving force transmitting mechanisms 70, 110 from the motor 67. Is set so as to be faster than the peripheral speed of the separating roller 34 that rotates. In other words, the peripheral speeds of the suction roller 33 and the separation roller 34 are slower than the peripheral speeds of the transport rollers 35A, 35B, 35C, 35D and the paper discharge roller 36. As shown in FIG. 23, the original G1 fed from the paper feed tray 30 to the original conveyance path 32 is nipped and conveyed by the conveyance roller 35A and the pinch roller 37 while being pressed against the separation roller 34. As shown in FIG. 12, the separation roller 34 is allowed to idle for approximately one turn in the feeding direction by the one-turn clutch 112. Therefore, as shown in FIG. 24, the separation roller 34 that is in pressure contact with the original G1 is rotated by the original G1 conveyed at a predetermined speed by the conveying roller 35A and idles so as to advance in the feeding direction from the shaft 111. .

  As shown in FIG. 25, when the first original G1 is completely fed from the paper feed tray 30 to the original conveyance path 32, the original G1 is separated from the separation roller. As a result, the idling of the separation roller 34 that has been rotated by the original G1 is stopped. As shown in FIG. 24, due to the idling of the separation roller 34, the locking piece 118 of the separation roller 34 advances in the feeding direction with respect to the pin 117 of the shaft 111. A driving force is transmitted to the shaft 111 from the motor 67, but the separation roller 34 does not rotate until the pin 117 rotates to a position where it engages with the locking piece 118. Therefore, the second original G2 that is in pressure contact with the separation roller 34 is not fed to the original conveyance path 32 until the separation roller 34 rotates. On the other hand, the document G1 fed to the document transport path 32 is transported through the document transport path 32 by the rotation of the transport rollers 35A and 35B. As a result, as shown in FIG. 25, a predetermined gap is formed in the transport direction between the first document G1 and the second document G2. If the shaft 111 rotates until the pin 117 engages with the locking piece 118, the rotation of the shaft 111 is transmitted to the separation roller 34 by the pin 117 and the locking piece 118, and the separation roller 34 rotates in the feeding direction. To do. Thereby, as shown in FIG. 26, the second original G2 is fed to the original conveyance path 32. In this manner, each document Gn can be fed to the document transport path 32 continuously and at high speed with a predetermined gap without driving the paper feed solenoid 88 for each document Gn. As shown in FIG. 25, the second front sensor 53 is turned off when the trailing end of the document G1 passes, and thereafter, the leading end of the document G2 passes as shown in FIG. It turns on.

  As shown in FIG. 26, the original G1 is conveyed so as to be reversed downward by the curved portion 32B of the original conveying path 32, and the rear sensor 54 detects the leading end of the original G1 in the conveying direction and is turned on. Since the front end of the document G in the conveyance direction reaches the reading position after a predetermined time has been detected by the rear sensor 54, the control unit 60 operates the image reading unit 22 when the front end of the document G1 in the conveyance direction reaches the reading position. The original G1 is read. The original G1 passes through the reading position with the first side facing the image reading unit 22, and the image on the first side of the original G is read by the image reading unit 22. The rear sensor 54 is turned off when detecting the rear end of the document G1 in the conveyance direction. The control unit 60 ends the image reading of the document G1 by the image reading unit 22 after the rear sensor 54 is turned off and a predetermined time has elapsed.

  Since the motor 67 is CW rotation, as shown in FIG. 27, the guide flap 50 maintains the first guiding posture. The guide flap 50 guides the document G <b> 1 to the paper discharge tray 31 side of the document transport path 32 at the connection position 38. The paper discharge roller 36 and the pinch roller 37 nip the original G 1 and discharge it from the original conveyance path 32 to the paper discharge tray 31. If the rear sensor 54 detects the leading edge of the second original G2 in the conveyance direction and is turned on, the control unit 60 operates the image reading unit 22 to read an image of the original G2 after a predetermined time has elapsed. Further, after the idling of the original G2, the separation roller 34 that has been stopped for a predetermined time rotates, whereby the third original G3 is fed to the original conveying path 32. By repeating these operations, the ADF 3 sequentially feeds the originals G1, G2, G3,... On the paper feed tray 30 to the original conveyance path 32, and the image reading unit 22 makes the original originals G1, G2, and so on. The images G3,... Are read, and the read originals G1, G2, G3,.

  As shown in FIG. 21, after the last document Gk placed on the paper feed tray 30 is discharged from the document transport path 32, the control unit 60 switches the rotation of the motor 67 from CW rotation to CCW rotation and feeds it. The paper solenoid 88 is turned on. Whether or not the document Gk placed on the paper feed tray 30 is the last document is determined by the first front sensor 53 when the second front sensor 53 detects the rear end of the document Gk in the transport direction and is turned off. Judgment is made by whether or not 52 is off. If the first front sensor 52 is off, the original Gk is the last original placed on the paper feed tray 30, and if it is on, it is determined that the next original exists on the paper feed tray 30. When the rotation of the motor 67 is switched from CW rotation to CCW rotation and the paper feed solenoid 88 is turned on, the driving force is transmitted from the planetary gear unit 75 as shown in FIG. The shaft 111 rotates in the direction opposite to the feeding direction. The rotation of the shaft 111 is transmitted to the arm 29, and the arm 29 swings so that the arm 29 rises, so that the paper feed roller 33 moves away from the guide surface of the document conveyance path 32. As a result, the original Gn to be read next can be inserted beyond the lower side of the paper feed roller 33 until it contacts the separation roller 34. Thereafter, the control unit 60 stops the motor 67 and the image reading in the single-sided reading mode is completed.

  Next, double-sided reading will be described. FIG. 28 is a timing chart showing the operation of the image reading apparatus 1 in the double-sided reading mode. Before the original Gn is fed, as shown in FIG. 22 in the description of the single-sided reading mode, the guide flap 50 moves the conveying path at the connection position 38 from the reading position side of the original conveying path 32 to the discharge tray 31 side. It is in a continuous position. The guide flap 46 is in a third guiding attitude, that is, a position where the conveying path at the crossing position 40 is continued from the paper feed tray 30 side of the document conveying path 32 to the reading position side, and the guide flap 47 is in the fifth guiding attitude. That is, the conveyance path at the crossover position 40 is in a position where it continues from the terminal end 41 side of the switchback path 39 to the reading position side of the document conveyance path 32.

  When reading start is input to the image reading apparatus 1, the first front sensor 52 detects whether or not the document Gn is placed on the paper feed tray 30. When the control unit 60 determines that the document Gn is not placed on the paper feed tray 30, the control unit 60 displays an error message “No Document” on the display unit of the image reading apparatus 1. If the document Gn is placed on the paper feed tray 30, the motor 67 is driven by CW rotation.

  The controller 60 drives the motor 67 by CW rotation and turns on the paper feed solenoid 88. As a result, as shown in FIGS. 7 and 8, the planetary gear device 75 of the driving force transmission mechanism 70 is unlocked by the locking mechanism 86, and the planetary gears 79, 80 are based on the rotation of the sun gear 76. Is revolved by CCW rotation to transmit the driving force to the transmission gear 94. As a result, the driven gear 95 rotates CW. As the driven gear 95 rotates CW, the driving force is transmitted to the arm 29 and the arm 29 is lowered. As a result, the suction roller 33 comes into pressure contact with the document G1 on the paper feed tray 30. In addition, the CW rotation of the driven gear 95 is transmitted to the suction roller 33 and the separation roller 34 by the driving force transmission mechanism 110, and the suction roller 33 and the separation roller 34 rotate in the feeding direction, whereby the document G1 is fed to the document conveyance path 32. It is carried to. When a plurality of documents Gn are placed on the sheet feed tray 30, the document G2 directly below the document G2 may be double-fed along with the document G1 at the uppermost position. It is restrained by the separation pad provided at the facing position.

  In the document conveyance path 32, the driving force from the motor 67 is transmitted to the conveyance rollers 35 </ b> A, 35 </ b> B, 35 </ b> C, 35 </ b> D and the paper discharge roller 36 by the driving force transmission mechanism 120, and each roller is downstream from the upstream side of the document conveyance path 32. The original Gn is conveyed to the side, that is, rotated in the conveyance direction. The document G1 fed from the sheet feed tray 30 to the document transport path 32 is nipped by the transport roller 35A and the pinch roller 37 and is transmitted with a rotational force, so that the document G1 is transported to the intersection position 40 through the document transport path 32. . The second front sensor 53 is turned on when the document G1 is fed to the document transport path 32.

  Since the guide flap 47 closes the conveyance path from the paper feed tray 30 side of the document conveyance path 32 to the intersection position 40, the document G 1 conveyed to the intersection position 40 abuts on the guide flap 47. In the description of the single-sided reading mode, as shown in FIG. 23, the guide flap 47 changes its posture from the fifth guide posture to the sixth guide posture so as to be pushed by the document G1 being transported through the document transport path 32. To do. As a result, the conveyance path from the paper feed tray 30 side to the reading position side of the document conveyance path 32 continues and the conveyance path to the terminal end 41 side of the switchback path 39 is closed. In addition, the conveyance path to the connection position 38 side of the switchback path 39 is closed by the guide flap 46. Therefore, the document G1 that has reached the crossing position 40 from the paper feed tray 30 side of the document transport path 32 is guided by the guide flap 46 and the guide flap 47, and does not enter any direction of the switchback path 39. The document is conveyed to the reading position side of the document conveyance path 32.

  As described in the single-sided reading mode, the peripheral speeds of the transport rollers 35A, 35B, 35C, and 35D and the paper discharge roller 36 are set to be higher than the peripheral speed of the separation roller 34. The separation roller 34 is idled by the original G1 being nipped between the conveying roller 35A and the pinch roller 37 while being pressed, and thereby the conveying direction to the first original G1 and the second original G2. A predetermined gap is formed. As shown in FIG. 29, the control unit 60 switches the rotation of the motor 67 from the CW rotation to the CCW rotation before the document G2 is fed, that is, before the idle separation roller 34 rotates again. The controller 60 determines whether the second front sensor 53 has been turned on after detecting the leading end of the document G1 in the transport direction, or the elapsed time after the second front sensor 53 has been turned off by detecting the trailing end of the document G1 in the transport direction. The timing for switching the rotation of the motor 67 can be determined based on the rotation amount of the motor.

  When the rotation of the motor 67 is switched from CW rotation to CCW rotation, as shown in FIG. 10, the support arm 78 of the planetary gear device 75 is locked by the locking mechanism 86 and held in the disengagement posture. As a result, transmission of the driving force to the driven gear 95 is cut, and the shaft 111 that supports the separation roller 34 stops. In the figure, the surface indicated by “1” in the document Gn is the first surface read first in the duplex reading, and the surface indicated by “2” is the second surface read later. The surface and the second surface are in a relationship of front and back surfaces.

  As shown in FIGS. 13 to 15, the driving force transmission mechanism 120 is configured such that each of the transport rollers 35 </ b> A, 35 </ b> B, 35 </ b> C, 35 </ b> D and the paper discharge roller regardless of whether the motor 67 rotates CW or CCW. The driving force in the conveying direction is transmitted to 36. Therefore, even after the rotation of the motor 67 is switched, the original G1 is conveyed along the original conveyance path 32 toward the reading position by the conveyance roller 35B or the like.

  In the driving force transmission mechanism 150, when the rotation of the motor 67 is switched from CW rotation to CCW rotation, the driving cutting mechanism 151 holds the planetary gear device 153 in the disengagement posture and cuts the driving force transmission to the driven gear 168. To do. Thereby, the switchback roller 43 stops. The driving force transmission mechanism 170 changes the posture of the guide flap 50 to the second guide posture by switching the rotation of the motor 67 from CW rotation to CCW rotation. Note that the guide flap 47 returns from the sixth guide position to the fifth guide position when the rear end of the document G1 in the transport direction passes the crossing position 40.

  As shown in FIG. 30, the document G1 is conveyed so as to be turned downward by the curved portion 32B of the document conveyance path 32, and the rear sensor 54 detects the leading end of the document G1 in the conveyance direction and is turned on. Since the front end of the document G in the conveyance direction reaches the reading position after a predetermined time has been detected by the rear sensor 54, the control unit 60 operates the image reading unit 22 when the front end of the document G1 in the conveyance direction reaches the reading position. The original G1 is read. The original G1 passes through the reading position with the first side facing the image reading unit 22, and the image on the first side of the original G is read by the image reading unit 22. The rear sensor 54 is turned off when detecting the rear end of the document G1 in the conveyance direction. The control unit 60 ends the image reading of the first surface of the document G1 by the image reading unit 22 after the rear sensor 54 is turned off and a predetermined time has elapsed.

  As shown in FIG. 31, the document G <b> 1 whose first surface has been read is guided by the guide flap 50, and enters the connection position 38 from the document conveyance path 32 to the switchback path 39. The switchback sensor 55 is turned on by detecting the leading end of the document G1 entering the switchback path 39 in the conveyance direction. In response to this, the control unit 60 turns on the switchback solenoid 161. As a result, when the document G1 is drawn into the switchback path 39, the support arm 156 of the planetary gear unit 153 is released from the drive cutting mechanism 151, and the motor 67 rotates the CCW as shown in FIG. The planetary gear device 153 that has received the driving force transmission transmits the driving force of CW rotation to the driven gear 168, and the switchback roller 43 rotates in the retracting direction.

  Since the guide flap 46 closes the conveyance path from the switchback path 39 to the crossover position 40, the document G that has entered the switchback path 39 contacts the guide flap 46 when it reaches the crossover position 40. As shown in FIG. 31, the guide flap 46 changes its posture from the third guide posture to the fourth guide posture so that the switchback path 39 is pushed up by the conveyed document G. As a result, the conveyance path from the connection position 38 side of the switchback path 39 to the terminal end 41 side of the switchback path 39 continues, and the conveyance path to the reading position side of the document conveyance path 32 is closed. The guide flap 47 closes the conveyance path of the document conveyance path 32 toward the paper feed tray 30 side. Accordingly, the document G that has reached the crossover position 40 from the connection position 38 side of the switchback path 39 is guided by the guide flap 46 and the guide flap 47 and conveyed to the switchback path 39 without entering the document conveyance path 32. Is done. Then, the document G is nipped between the switchback roller 43 and the pinch roller 44, and is conveyed to the terminal end 41 side through the switchback path 39 by the rotation of the switchback roller 43 in the drawing direction.

  As shown in FIG. 32, after the trailing end of the document G1 in the transport direction has completely entered the end 41 side beyond the crossing position 40 of the switchback path 39, the control unit 60 changes the rotation of the motor 67 from CCW rotation to CW rotation. Switch to rotation. The switchback sensor 55 detects the trailing edge in the conveyance direction of the document G1 conveyed through the switchback path 39 and turns off. After a predetermined time has elapsed, the trailing edge in the conveyance direction of the document G1 passes through the crossing position 40. Therefore, the control unit 60 determines that the trailing end of the document G1 in the transport direction is the crossover position 40 of the switchback path 39 based on the detection signal of the switchback sensor 55 and the transport distance or transport time of the transport roller 35D and the switchback roller 43. It is determined that the vehicle has completely entered the terminal 41 side beyond When the rotation of the motor 67 is switched, the document G1 that is nipped between the switchback roller 43 and the pinch roller 44 and protrudes from the terminal end 41 is returned to the crossover position 40.

  When a part of the document G1 projects from the end 41 of the switchback path 39 to the outside of the ADF 3, a part of the projected document G is supported by the document support unit 42. Further, when the document G1 passes through the crossing position 40 and is separated from the guide flap 46, the guide flap 46 rotates downward and returns to the third guiding posture.

  When the motor 67 is switched from CCW rotation to CW rotation, the planetary gear device 153 of the driving force transmission mechanism 150 rotates the support arm 156 CW to drive the driving force of the motor 67 to the driven gear 168 as shown in FIG. And the driven gear 168 rotates CCW. As a result, the switchback roller 43 rotates in the return direction. In response to this, the document G1 is switchback conveyed so as to return to the crossover position 40 through the switchback path 39.

  As shown in FIGS. 13 to 15, the driving force transmission mechanism 120 is configured such that each of the transport rollers 35 </ b> A, 35 </ b> B, 35 </ b> C, 35 </ b> D and the paper discharge roller regardless of whether the motor 67 rotates CW or CCW. The driving force in the conveying direction is transmitted to 36. Accordingly, even after the rotation of the motor 67 is switched, the transport rollers 35A, 35B, 35C, and 35D and the paper discharge roller 36 rotate in the transport direction.

  When the rotation of the motor 67 is switched from CW rotation to CCW rotation, the driving force transmission mechanism 70 holds the planetary gear device 75 in the disengagement posture and transmits the driving force to the driven gear 95. Disconnected. After that, since the paper feed solenoid 88 is not operated, the planetary gear device 75 is held in the disengagement posture even when the motor 67 rotates CW. The driving force transmission mechanism 170 changes the posture of the guide flap 50 to the first guide posture by switching the rotation of the motor 67 from CCW rotation to CW rotation.

  As shown in FIG. 33, the document G1 returned from the switchback path 39 comes into contact with the guide flap 46 in the third guide posture at the crossover position 40. The guide flap 46 does not rotate downward from the third guiding posture. Therefore, the conveyance path from the terminal end 41 side of the switchback path 39 to the reading position side of the document conveyance path 32 continues, and the conveyance path to the connection position 38 side of the switchback path 39 is closed. Further, the guide flap 47 closes the conveyance path to the paper feed tray 30 side of the document conveyance path 32. Therefore, the document G1 is guided by the guide flap 46 and the guide flap 47, and does not enter the connection position 38 side of the switchback path 39 or the paper feed tray 30 side of the document transport path 32, and the end of the switchback path 39. It is conveyed from the 41 side to the reading position side of the document conveying path 32. When the original G1 is returned from the switchback path 39 to the upstream side of the reading position of the original conveyance path 32, the front and rear ends of the original G1 are reversed from the state where the original G1 was first conveyed in the original conveyance path 32. Thus, the document conveyance path 32 is retransmitted. In this way, the original G1 is switched back and conveyed. Then, the document G1 is transported through the document transport path 32 with the second surface facing the reading position.

  When reading the first surface of the original G1, as shown in FIG. 29, the controller 60 controls the rotation of the motor 67 to CW when the original G1 reaches a predetermined position upstream of the reading position of the original conveyance path 32. Switch from rotation to CCW rotation. The driving force transmission mechanism 120 transmits the driving force in the conveyance direction to each of the conveyance rollers 35A, 35B, 35C, and 35D and the paper discharge roller 36 regardless of the rotation direction of the motor 67. Therefore, the rotation of the motor 67 is switched. Thereafter, the original G1 is conveyed toward the reading position on the original conveyance path 32 by the conveyance roller 35B and the like.

  When the rotation of the motor 67 is switched from CW rotation to CCW rotation, the driving force transmission mechanism 150 is rotated by the support arm 156 of the planetary gear device 153 in the CCW direction and is locked by the drive cutting mechanism 151 to be in a detached posture. Thereby, the driving force transmission from the planetary gear device 153 to the driven gear 168 is cut off, and the switchback roller 43 stops. Therefore, as shown in FIG. 34, the front end side of the document G1 in the transport direction is nipped by the transport roller 35B and the pinch roller 37, and the rear end side of the document G1 in the transport direction is nipped by the switchback roller 43 and the pinch roller 444. Even if the rotation of 67 is switched, the switchback roller 43 does not rotate in the pull-in direction. The switchback roller 43 from which the driving force transmission from the motor 67 is cut off is rotated in the return direction by the original G1 conveyed by the rotation of the conveying roller 35B.

  Since the feed solenoid 88 is not operated after the locking mechanism 86 holds the planetary gear device 75 in the disengagement posture, the planetary gear device 75 is connected to the driving force transmission mechanism 70 even if the motor 67 rotates CCW. It is held in the separation posture. The driving force transmission mechanism 170 changes the posture of the guide flap 50 to the second guide posture by switching the rotation of the motor 67 from CW rotation to CCW rotation.

  When the front end of the document G1 in the transport direction is detected by the rear sensor 54 and the front end in the transport direction reaches the reading position, as shown in FIG. 35, the control unit 60 sends the image reading unit 22 to the second surface of the document G1. Have the image read. The original G1 after the second surface is read is guided by the guide flap 50 and enters the connection position 38 from the original conveyance path 32 to the switchback path 39. When the rear end of the document G1 in the transport direction is detected by the rear sensor 54 and the rear end in the transport direction reaches the reading position, the control unit 60 ends the image reading of the document G1 by the image reading unit 22.

  When the switchback sensor 55 detects the leading edge of the document G1 that has entered the switchback path 39 and is turned on, the control unit 60 turns on the switchback solenoid 161. As a result, when the document G1 is drawn into the switchback path 39, the support arm 156 of the planetary gear unit 153 is released from the drive cutting mechanism 151, and the motor 67 rotates the CCW as shown in FIG. The planetary gear device 153 that has received the driving force transmission transmits the driving force of CW rotation to the driven gear 168, and the switchback roller 43 rotates in the retracting direction.

  The document G1 that has reached the crossover position 40 pushes up the guide flap 46 to change the posture from the third guide posture to the fourth guide posture in the same manner as in FIG. Enter the 41st side. Similarly to FIG. 32, after the rear end of the document G1 in the conveyance direction has completely entered the end 41 side beyond the crossing position 40 of the switchback path 39, the control unit 60 rotates the rotation of the motor 67 by CCW. Is switched to CW rotation, the switchback roller 43 is rotated in the returning direction, and the original G1 is returned to the crossover position 40. 33, the document G1 returned from the switchback path 39 is guided by the guide flap 46 and the guide flap 47, and from the end 41 side of the switchback path 39 to the reading position side of the document conveyance path 32. It is conveyed to. As a result, the original G1 is retransmitted on the original conveyance path 32 in a state where the leading end and the rear end are reversed again, that is, in a state where the original G1 is first fed to the original conveyance path 32.

  The driving force transmission mechanism 120 transmits the driving force in the conveyance direction to each of the conveyance rollers 35A, 35B, 35C, and 35D and the paper discharge roller 36 regardless of the rotation direction of the motor 67, so that each of the conveyance rollers 35A, 35B, 35C and 35D and the paper discharge roller 36 rotate in the transport direction. The driving force transmission mechanism 70 is in a state where the locking mechanism 86 holds the planetary gear device 75 in the disengagement posture, and cuts off the driving force transmission to the driven gear 95. The driving force transmission mechanism 170 changes the posture of the guide flap 50 to the first guide posture by switching the rotation of the motor 67 from CCW rotation to CW rotation.

  Thereafter, the document G1 passes the reading position with the first surface facing the document G1, is guided to the connection position 38 by the guide flap 50 toward the discharge tray 31, and the first surface is lowered by the discharge roller 36. Is discharged to the paper discharge tray 31. When the next document G2 is set on the paper feed tray 30, that is, when the first front sensor 52 is on, the control unit 60 turns on the paper feed solenoid 88 and the planetary gear by the locking mechanism 86. The locking of the support arm 78 of the device 75 is released, the driving force is transmitted from the motor 67 to the driven gear 95 by the driving force transmission mechanism 70, and the separation roller 34 is rotated in the feeding direction. As a result, the original G2 on the paper feed tray 30 is fed to the original conveyance path 32, and image reading on both sides of the original G2 is performed in the same manner as described above.

  Then, similarly to the single-sided reading mode, after discharging the last document Gk placed on the paper feed tray 30 from the document transport path 32 to the paper discharge tray 31, the control unit 60 changes the rotation of the motor 67 from the CW rotation. While switching to CCW rotation, the paper feed solenoid 88 is turned on. As a result, as shown in FIG. 11, the driving force is transmitted from the planetary gear device 75, the driven gear 95 rotates CCW, and the shaft 111 rotates in the direction opposite to the feeding direction. The rotation of the shaft 111 is transmitted to the arm 29, and the arm 29 swings so that the arm 29 rises, so that the paper feed roller 33 moves away from the guide surface of the document conveyance path 32. As a result, the original Gn to be read next can be inserted beyond the lower side of the paper feed roller 33 until it contacts the separation roller 34. Thereafter, the control unit 60 stops the motor 67, and the image reading in the duplex reading mode is completed.

  In the present embodiment, it is assumed that a plurality of documents Gn placed on the paper feed tray 30 are discharged to the paper discharge tray 31 while maintaining the order, and the duplex reading operation by the image reading apparatus 1 is performed. However, if it is not necessary to match the order of the originals Gn placed on the paper feed tray 30 and the order of the originals Gn discharged to the paper discharge tray 31, the first position of the original Gn at the reading position is described. After the original is conveyed with the two surfaces facing each other, the original position Gn is transported to the discharge tray 31 side without causing the original Gn to enter the switchback path 39 again, and the original Gn is discharged to the discharge tray 31. It is good to do. As a result, the order of the originals Gn is not maintained on the paper discharge tray 31, but the last switchback conveyance can be omitted, so that the time required for reading both sides of the original Gn can be shortened.

  As described above, according to the present image reading apparatus 1, the single motor 67 causes the first surface and the second surface of the document Gn to face the reading position, and the document feed path 30 passes through the document transport path 32. Documents can be conveyed to the paper discharge tray 31. Further, a driving force transmission mechanism 70 that transmits a driving force from the motor 67 to the separation roller 34, a driving force transmission mechanism 120 that transmits a driving force to each of the transport rollers 35 A, 35 B, 35 C, and 35 D and the paper discharge roller 36, The driving force transmission mechanism 150 that transmits the driving force and the driving force transmission mechanism 170 that transmits the driving force to the guide flap 50 can be realized without using an electromagnetic clutch.

  In the single-sided reading mode, since the rotation direction of the motor 67 cannot be switched, high-speed and stable conveyance of the original Gn is realized. Further, since it is not necessary to release the locking of the support arm 78 of the driving force transmission mechanism 70 every time a plurality of documents Gn are fed, there is an advantage that operation noise during document conveyance can be reduced.

  In the image reading apparatus 1, a switchback path 39 for retransmitting the document Gn to the document conveyance path 32 extends from a connection position 38 on the downstream side of the reading position of the document conveyance path 32, and is upstream of the reading position. However, the transport path of the switchback path 39 is an example, and the present invention is limited to the transport path of the document transport path 32 and the switchback path 39 described in the embodiment. Of course, it is not. Therefore, the guide flap 46 and the guide flap 47 can be appropriately changed according to the transport path of the switchback path, and instead of the guide flaps 46 and 47, for example, an elastically deformable film may be adopted as the guide member. .

FIG. 1 is a longitudinal sectional view showing a configuration of an image reading apparatus 1 according to an embodiment of the present invention. FIG. 2 is an enlarged view showing the configuration of the crossover position 40. FIG. 3 is an enlarged view showing the configuration of the connection position 38. FIG. 4 is an enlarged view showing the configuration of the first front sensor 52. FIG. 5 is a block diagram illustrating a configuration of the control unit 60. FIG. 6 is a perspective view showing an external configuration of the image reading apparatus 1. FIG. 7 is a diagram illustrating a configuration of the driving force transmission mechanism 70. FIG. 8 is a diagram illustrating a configuration of the driving force transmission mechanism 70. FIG. 9 is a diagram illustrating the configuration of the planetary gear device 75 and the locking mechanism 86. FIG. 10 is a diagram illustrating a configuration of the driving force transmission mechanism 70. FIG. 11 is a diagram illustrating a configuration of the driving force transmission mechanism 70. FIG. 12 is a diagram illustrating a configuration of the driving force transmission mechanism 110. FIG. 13 is a diagram illustrating a configuration of the driving force transmission mechanism 120. FIG. 14 is a diagram illustrating a configuration of the driving force transmission mechanism 120. FIG. 15 is a diagram illustrating a configuration of the driving force transmission mechanism 120. FIG. 16 is a diagram illustrating a configuration of the driving force transmission mechanism 150. FIG. 17 is a diagram illustrating a configuration of the driving force transmission mechanism 150. FIG. 18 is a diagram illustrating a configuration of the driving force transmission mechanism 150. FIG. 19 is a diagram illustrating a configuration of the driving force transmission mechanism 170. FIG. 20 is a diagram illustrating a configuration of the driving force transmission mechanism 170. FIG. 21 is a timing chart of the single-sided reading mode. FIG. 22 is a schematic diagram showing an image reading operation in the single-sided reading mode. FIG. 23 is a schematic diagram illustrating an image reading operation in the single-sided reading mode. FIG. 24 is a diagram illustrating a state where the separation roller 34 is idling. FIG. 25 is a schematic diagram illustrating an image reading operation in the single-sided reading mode. FIG. 26 is a schematic diagram illustrating an image reading operation in the single-sided reading mode. FIG. 27 is a schematic diagram illustrating an image reading operation in the single-sided reading mode. FIG. 28 is a timing chart of the duplex reading mode. FIG. 29 is a schematic diagram showing an image reading operation in the duplex reading mode. FIG. 30 is a schematic diagram showing an image reading operation in the duplex reading mode. FIG. 31 is a schematic diagram showing an image reading operation in the duplex reading mode. FIG. 32 is a schematic diagram showing an image reading operation in the duplex reading mode. FIG. 33 is a schematic diagram showing an image reading operation in the duplex reading mode. FIG. 34 is a schematic diagram showing an image reading operation in the duplex reading mode. FIG. 35 is a schematic diagram showing an image reading operation in the duplex reading mode. FIG. 36 is a schematic diagram showing document conveyance for double-sided reading by a conventional automatic document conveyance device. FIG. 37 is a schematic diagram showing document conveyance for double-sided reading by a conventional automatic document conveyance device.

Explanation of symbols

3 ... ADF (sheet material transport device)
29... Arm 30... Paper feed tray (sheet material placement section)
31 ... Paper discharge tray (sheet material discharge part)
32 ... Document transport path (sheet material transport path)
33 ... Suction roller (feeding means)
34 ... Separation roller (feeding roller, feeding means)
35A, 35B, 35C, 35D ... Conveying roller (sheet material conveying means, sheet material conveying roller)
36... Discharge roller (sheet material conveying means, sheet material conveying roller)
37 ... Pinch roller (sheet material conveying means)
38 ... Connection position 39 ... Switchback path (switchback transport path)
43 ... Switchback roller (switchback conveying means)
44 ... Pinch roller (switchback conveying means)
50. Guide flap (guide means)
60... Control unit (drive control means)
67 ... Motor (drive source)
70: Driving force transmission mechanism (first driving force transmission means)
74: Transmission gear (first transmission gear)
76 ... Sun gear 78 ... Support arm 79 ... Planetary gear (first planetary gear)
87... Locking member 94... Transmission gear (second transmission gear)
120 ... Driving force transmission mechanism (second driving force transmission means)
150: Driving force transmission mechanism (third driving force transmission means)
151... Driving force cutting mechanism (driving force cutting means)
170: Driving force transmission mechanism (fourth driving force transmission means)

Claims (5)

A sheet material placement unit on which a sheet material for performing double-sided processing is placed;
A sheet material discharge unit for discharging the sheet material subjected to the double-side treatment;
A sheet material conveyance path that connects the sheet material placement unit and the sheet material discharge unit via a processing position;
A switchback conveying path connected to a predetermined position of the sheet material conveying path, for reversing the leading edge and the trailing edge of the sheet material from the downstream side of the processing position and returning to the upstream side of the processing position;
A feeding means that is provided in the vicinity of the sheet material placement portion of the sheet material conveyance path, and sequentially feeds the sheet material placed on the sheet material placement portion;
A sheet material conveying means provided in the sheet material conveying path for conveying the sheet material from the sheet material placing unit to the sheet material discharging unit;
A switchback conveying means provided in the switchback conveying path for conveying the sheet material in a switchback;
A first guiding posture for guiding the sheet material to a conveyance path in which the sheet material conveyance path is continuous, a sheet material conveyance path, and a switchback conveyance path at a connection position between the sheet material conveyance path and the switchback conveyance path; Guiding means for changing the posture to a second guiding posture for guiding the sheet material to the continuous conveyance path,
A single driving source for applying a driving force to the feeding means, the sheet material conveying means, the switchback conveying means, and the guiding means by rotating in both forward and reverse directions;
A driving force in the feeding direction is transmitted to the feeding means based on rotation in one of the forward and reverse directions of the driving source, and to the feeding means based on switching of rotation in the other direction. First driving force transmission means for cutting off transmission of the driving force;
Regardless of the rotation direction of the driving source, second driving force transmitting means for transmitting a driving force in the conveying direction to the sheet material conveying means;
The driving force in the pull-in direction is transmitted to the switchback conveying means based on rotation in one of the forward and reverse directions of the driving source, and the return direction to the switchback conveying means is based on rotation in the other direction. Third driving force transmission means for transmitting the driving force of
When the drive source is switched from rotation in one direction of forward / reverse bidirectional to rotation in the other direction, transmission of drive force from the third drive force transmission means to the switchback transport means is cut off. Driving force cutting means for
Based on the rotation of the drive source in either one of the forward and reverse directions, the guide means is changed to the first guide attitude, and based on the rotation in the other direction, the guide means is changed to the second guide attitude. A fourth driving force transmission means for changing the posture to
The single-sided processing conveyance mode in which the driving source is rotated only in one of the forward and reverse directions, and the leading edge of the sheet material conveyed through the sheet material conveyance path reaches a predetermined position upstream of the processing position. When the sheet material is pulled into the switchback conveyance path, the cutting of the driving force by the driving force cutting means is released, and the sheet material is drawn into the switchback conveyance path. Drive control means having a double-sided processing conveyance mode for switching the rotation direction of the drive source later. The first driving force transmission means is
A first transmission gear for transmitting a driving force from the driving source;
A sun gear meshing with the first transmission gear;
A first planetary gear meshing with the sun gear;
A second transmission gear that is engaged with the first planetary gear to transmit a driving force to the feeding means;
A rotating member that is rotatably provided coaxially with the sun gear so that the first planetary gear is pivotally supported and the first planetary gear engages with the second transmission gear;
The seat according to claim 1, further comprising: a locking member that is locked to the rotating member and that holds the first planetary gear in a disengagement posture in which the first planetary gear is detached from the second transmission gear. Material transport device.   The drive control means is configured to feed the plurality of sheet materials stacked on the sheet material placement portion to the sheet material conveyance path by the rotating member by the locking member of the first driving force transmission means. The sheet material conveying apparatus according to claim 2, wherein the sheet material is released. The feeding unit is in pressure contact with the sheet material placed on the sheet material placing unit and rotates based on a driving force transmitted by the first driving force transmission unit, and the feeding roller A clutch that transmits a driving force to the shaft of the roller and allows the feeding roller to idle in a predetermined range;
The sheet material conveying means is brought into pressure contact with the sheet material at a predetermined position in the sheet material conveying path, and rotates based on the driving force transmitted by the second driving force transmitting means, thereby causing the sheet material to move in a predetermined direction. A sheet material conveying roller
The first driving force transmitting means is driven from the driving source so that the feeding roller has a lower peripheral speed than the peripheral speed of the sheet material conveying roller rotated by the second driving force transmitting means. The sheet material conveying device according to claim 2, which transmits force. The feeding means further includes an arm that swings so as to come into contact with and separate from the sheet material placed on the sheet material placement portion based on the driving force transmitted by the first driving force transmission means, A suction roller that is pivotally supported on the distal end side of the arm and rotated based on the driving force transmitted by the first driving force transmitting means;
The first driving force transmission means further includes a second planetary gear meshing with the sun gear, and the second planetary gear is pivotally supported by the rotating member, and the rotating member is unidirectional. The second planetary gear is disengaged from the second transmission gear by rotating, the first planetary gear is engaged with the second transmission gear, and the second planetary gear is rotated by rotating in the other direction. The engagement member is rotatably provided coaxially with the sun gear so as to mesh with the second transmission gear and to disengage the first planetary gear from the second transmission gear. And the first planetary gear and the second planetary gear are held in the disengagement posture separated from the second transmission gear,
The drive control means is configured to engage the rotating member by the locking member of the first driving force transmitting means after all the sheet materials stacked on the sheet material placing portion are discharged to the sheet material discharge portion. The sheet material conveying device according to claim 4, wherein the sheet material conveying device is configured to release the stop and switch the rotation direction of the driving source.

Images