JP2005060076A - Automatic document feeder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic document feeder capable of speedily inverting and reading a double-side document by omitting paper delivery completion wait time of a preceding document and paper delivery operation start wait time of an inverted document after completion of paper delivery. <P>SOLUTION: This automatic document feeder 1 is constituted in such a way that a double-side read document and a surface reading document are arranged in parallel on a contact glass 18 at a document interval in which a tip of the surface reading document is conveyed to a position where a paper delivery inlet sensor 16 detects it simultaneously with completion of delivery of the double-side read document when two documents of the double-side read document and the surface reading document are arranged in parallel on the contact glass 18 and delivery operation of the double-side read document and inversion operation of the surface reading document are continuously performed in document double-side reading mode. Consequently, it is possible to prevent the occurrence of jamming and breakage of the documents and shorten conveyance time of double-side document by omitting waste time from completion of delivery of the double-side read document to the start of inversion of the surface reading document to improve processing speed when reading double sides. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an automatic document conveying device, and more particularly, to an automatic document conveying device that appropriately detects the occurrence of a jam when a document is switched back and discharged through a switchback conveying path.

  2. Description of the Related Art Conventionally, in an image reading apparatus such as a copying machine, a facsimile machine, and a scanner apparatus, an automatic document conveying device that automatically conveys a document to a document reading position of the image reading device is mounted in order to improve document reading efficiency. It has become to.

  In this automatic document feeder, the documents fed one by one in the page order are discharged as they are onto the discharge tray provided on the side of the automatic document feeder or image reader with the document reading surface facing down. In addition, the straight paper discharge method that discharges the next page of documents one after the other, and the document after reading the image are turned so that the scanned document surface faces upward and is placed on the upper output tray of the automatic document feeder. In general, an upper discharge method is used in which the originals of the next page are sequentially stacked and discharged.

  In the straight paper discharge method, the page order is aligned, but a mechanism for stacking the paper to be discharged such as a paper discharge tray is required on the side of the automatic document feeder or the image reading device. There is a problem that the set area (occupied space) becomes large.

  On the other hand, the upper discharge method discharges to the upper part of the automatic document feeder, so it occupies a small space and does not require a special mechanism for stocking documents such as a discharge tray. In this case, the front and back sides of the document are reversed, and there is a problem that in the case of a plurality of documents, the page order is reversed and it takes time to rearrange the page order.

  Conventionally, there has been proposed an automatic document feeder provided with a switchback mechanism that reverses a document that has been read by the upper discharge method and aligns the page order (see Patent Document 1).

  However, in the switchback mechanism, since the document is once pulled into the switchback conveyance path and sent again from the switchback conveyance path to the paper discharge side, a document jam occurs in the switchback conveyance path. There is a fear.

  In view of this, the present applicant has previously proposed an automatic document feeder and an image forming apparatus in which an expansion / contraction deformation sensor is provided in a switchback path to detect the presence or absence of a document jam in the switchback path (Patent Document 2). reference).

Japanese Patent Laid-Open No. 10-268442

JP 2002-348052 A

  However, in the prior art described in Patent Document 2, since an original jam in the switchback conveyance path is detected using the expansion / contraction deformation sensor, occurrence of bellows jam due to the deformation of the original in the switchback conveyance path. Can be detected, but the jammed paper stays in the switchback conveyance path without being deformed, the jam that has not reached the switchback conveyance path within a predetermined time, and the switchback conveyance path In order to ensure proper conveyance of the original document, it is impossible to detect the occurrence of other jams such as unreached jams due to the unconveyed document within a predetermined time from the paper to the paper discharge outlet. There was a need for improvement.

  Therefore, according to the first aspect of the present invention, a plurality of documents on the document table are separated one by one and conveyed to the document reading position on the contact glass, and the document at the document reading position where the image reading is completed is performed. The paper is once stored in the switchback transport path of the switchback unit and then turned back and sent out in the paper discharge direction. The document sent from the switchback unit is placed on the paper discharge tray on the paper discharge unit. When discharging, a paper discharge entrance original detection means for detecting a document conveyed from the contact glass to the paper discharge portion on the contact glass, and a switch for detecting the presence or absence of the document provided at the switchback conveyance path entrance Based on the detection result of the back entrance document detection means, an unreached jam due to the failure of the document transported from the paper discharge unit to the switchback transport path to the switchback transport path is detected. And detecting a jamming jam in which the document stays in the switchback conveyance path and a bellows jam due to deformation of the document in the switchback conveyance path based on the detection result of the switchback inlet document detection means, and a switchback inlet detection means Based on the detection result of the paper discharge original detection means for detecting the original discharged on the paper discharge tray by the paper discharge unit, due to the failure of the original conveyed from the switchback transfer path to the paper discharge unit. By detecting the unreached jam, not only the bellows jam in which the original is deformed in the switchback transport path, but also the unreached jam in the switchback transport path in which the original is not deformed, the staying jam in the switchback transport path, and the paper discharge Providing an automatic document feeder with good usability by detecting unreached jams to the top of the table and ensuring proper conveyance of the document. It is the target.

  According to the second aspect of the present invention, at least the switchback entrance original detection means is a reflection type photosensor, so that not only the bellows jam but also the unreachable jam to the switchback transfer path where the original does not deform, the switchback transfer path Automatic and better-use automatic manuscripts can be detected cheaply and easily by detecting jammed jams and unreached jams on the upper side of the output tray at low cost and ensuring proper conveyance of the manuscript at low cost. The object is to provide a transport device.

  According to the third aspect of the present invention, when the document is transported from the sheet discharge unit onto the sheet discharge table without passing through the switchback transport path, the detection result of the switchback entrance document detection means is detected. By ignoring, the erroneous detection of the switchback entrance document detection means is prevented, the malfunction due to the erroneous detection of the switchback entrance document detection means is prevented, and an automatic document transport apparatus with further improved usability is provided. The purpose is that.

  The invention according to claim 4 further includes a reversing unit that reverses the original conveyed from the conveying unit and returns the original to the conveying unit, and the conveying unit returns the original reversed by the reversing unit to the contact glass again. When transporting the original to the original reading position, when the double-sided original is read by the reversing unit after completion of reading, the switchback entrance By ignoring the detection result of the document detection means, when conveying a double-sided document that discharges the document without using the switchback unit, the detection result of the switchback entry document detection means is ignored, so that the switchback entry document detection means is ignored. To prevent the erroneous detection due to the erroneous detection of the switchback entrance original detection means, and to provide an automatic original conveying apparatus with better usability It is an object.

  The automatic document feeder according to the first aspect of the invention separates a plurality of documents on the document table one by one and conveys them to the document reading position on the contact glass, and the document reading position where the image reading is completed. The document is temporarily stored in the switchback conveyance path of the switchback unit via the paper discharge unit, then turned back and sent in the paper discharge direction, and the document sent from the switchback unit is discharged by the paper discharge unit. In an automatic document feeder for discharging onto a paper table, a discharge inlet document detecting means provided at the discharge section inlet for detecting a document conveyed from the contact glass to the paper discharge section, and the switchback transport A switchback entrance document detection unit provided at the path entrance for detecting the presence or absence of a document, and a discharged document detection unit for detecting a document discharged onto the discharge table by the discharge unit. The unreachable of the document transported from the paper discharge unit to the switchback transport path based on the detection results of the paper discharge entrance original detection means and the switchback entrance original detection means due to the failure to reach the switchback transport path Detecting a jam, detecting a stay jam in the switchback transport path based on a detection result of the switchback entrance document detection means, and a bellows jam due to a deformation of the document in the switchback transport path, Detecting an unreached jam due to unsuccessful delivery of a document transported from the switchback transport path to the paper discharge unit based on detection results of the switchback entrance detection unit and the paper discharge document detection unit. The above-mentioned purpose is achieved.

  In this case, for example, in the automatic document feeder, at least the switchback entrance document detection unit may be a reflective photosensor.

  For example, as described in claim 3, the automatic document feeder is configured to transfer the document from the paper discharge unit to the paper delivery table without passing through the switchback transport path. When the document is discharged, the detection result of the switchback entrance document detection means may be ignored.

  Further, for example, as described in claim 4, the automatic document feeder further includes a reversing unit that reverses the document conveyed from the conveying unit and returns it to the conveying unit, and the conveying unit includes: An automatic document conveying device that conveys a document reversed by the reversing unit to the document reading position on the contact glass again, wherein the document is a double-sided document, and is reversed by the reversing unit in conveying the document. Further, after the reading of the original is completed, when the original is discharged from the paper discharge unit onto the paper discharge tray, the detection result of the switchback entrance original detection means may be ignored.

  According to the automatic document feeder of the first aspect of the present invention, the plurality of documents on the document table are separated one by one and conveyed to the document reading position on the contact glass, and the document whose image has been read is completed. The document at the reading position is temporarily stored in the switchback conveyance path of the switchback unit via the paper discharge unit, then turned back and sent in the paper discharge direction, and the document sent from the switchback unit is sent by the paper discharge unit. When discharging onto the paper discharge tray, a paper discharge inlet original detection means for detecting a document conveyed from the contact glass to the paper discharge portion provided at the paper discharge portion entrance and a switchback conveyance path entrance is provided. Based on the detection result of the switchback entrance document detecting means for detecting presence / absence of the document transported from the paper discharge unit to the switchback transport path due to failure to reach the switchback transport path A jam is detected, a jamming jam in which the original stays in the switchback conveyance path and a bellows jam due to a deformation of the original in the switchback conveyance path is detected based on the detection result of the switchback entrance original detection means, and the switch Based on the detection result of the discharged document detecting means for detecting the document discharged on the discharge table by the back entrance detecting means and the discharge section, the discharge section of the document conveyed from the switchback conveying path to the discharged sheet portion. Unreachable jam due to failure to reach is detected, so not only the bellows jam that the document deforms in the switchback transport path, but also the jam that has not reached the switchback transport path where the document does not deform, and stay in the switchback transport path Jam and unreached jams to the upper side of the paper output tray can be detected, ensuring proper conveyance of documents and improving usability Kill.

  According to the automatic document feeder of claim 2, since at least the switchback entrance document detection means is a reflection type photosensor, not only the bellows jam but also the switchback conveyance path where the document is not deformed is not reached. Jam, jams in the switchback transport path, and unreached jams to the upper side of the paper output tray can be detected inexpensively and easily, ensuring the proper transport of documents at low cost and automatically. The transportation device can be made inexpensive and the usability can be further improved.

  According to the automatic document feeder of the invention described in claim 3, when the document is transported from the sheet discharge unit onto the sheet discharge table without passing through the switchback transport path, the switchback is performed. Since the detection result of the entrance document detection unit is ignored, the erroneous detection of the switchback entrance document detection unit can be prevented, and the malfunction due to the erroneous detection of the switchback entrance document detection unit can be prevented. Can be improved.

  According to the automatic document feeder of the invention described in claim 4, the automatic document feeder further includes a reversing unit that reverses the document conveyed from the conveying unit and returns it to the conveying unit, and the conveying unit is reversed by the reversing unit. When transporting the document again to the document reading position on the contact glass, after the reading of the document reversed by the reversing unit is completed in transporting the double-sided document, the document is discharged from the discharge unit onto the discharge table. In this case, since the detection result of the switchback entrance document detection means is ignored, in the conveyance of the double-sided document that discharges the document without using the switchback unit, the detection result of the switchback entry document detection means is ignored. It is possible to prevent erroneous detection of the switchback entrance document detection means and prevent malfunction due to erroneous detection of the switchback entrance document detection means, further improving the usability. Rukoto can.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, since the Example described below is a suitable Example of this invention, various technically preferable restrictions are attached | subjected, However, The scope of the present invention limits this invention especially in the following description. As long as there is no description of the effect, it is not restricted to these aspects.

  1 and 2 are diagrams showing an embodiment of an automatic document feeder according to the present invention. FIG. 1 is a schematic front view of an automatic document feeder 1 to which an embodiment of an automatic document feeder according to the present invention is applied. It is a block diagram.

  In FIG. 1, the automatic document feeder 1 is provided with a calling / separating unit 10, a paper feeding unit 20, a conveying unit 30, a reverse / paper discharging unit 40, a switchback unit 50, and the like in a housing 2. A contact glass 61 of an image reading apparatus (main body apparatus) such as an electrophotographic copying apparatus to which the automatic document feeder 1 is applied is provided at the lower part of the housing 2. In the automatic document feeder 1, a paper discharge tray (paper discharge table) 3 is formed in the upper part of the housing 2, and a document table 4 is provided above the paper discharge tray 3. The image reading unit of the image reading device irradiates the original conveyed to the original reading position on the contact glass 61 with reading light from a light source (not shown), and photoelectrically reflects the reflected light including the image information of the original reflected by the original. The image of the original is read by performing photoelectric conversion with the conversion element.

  A document to be read is set on the document table 4, and the document table 4 is provided with a document set sensor 13 for detecting the set document.

  The calling / separating unit 10 includes a calling roller 11, a separation roller 12, and the like. The calling roller 11 is rotated by a calling motor (not shown) to call a document set on the document table 4 and separate the separation roller. 12, only one original is separated.

  The paper feeding unit 20 includes a pull-out sensor 21, a paper feeding roller 22, a registration sensor 23, and the like. The paper feeding roller 22 is fed from the calling / separating unit 10 by being driven to rotate by a paper feeding motor (not shown). The original is fed to the conveyance unit 30.

  The conveyance unit 30 includes a conveyance belt 31, a conveyance roller 32, a plurality of rollers 33, and the like, and the image reading unit of the image reading apparatus is placed on the contact glass 61 in a state where the document rear end is set at the document reading position. When the image of the original is read, the conveyance roller 32 is disposed so as to cover the contact glass 61 by being rotated by a conveyance motor (not shown) and being stretched over the conveyance roller 32 and the plurality of rollers 33. 31 is rotated counterclockwise, and the document is conveyed to the reverse / paper discharge unit 40.

  As shown in an enlarged view in FIG. 2, the reversing / paper discharging unit (paper discharging unit, reversing unit) 40 includes a paper discharge inlet sensor (paper discharge inlet original detecting means) 41, a paper discharge roller 42, a reverse switching claw 43, A discharge exit sensor (discharged document detection means) 44, a discharge exit roller 45, and the like are provided. When the document is conveyed by the conveyor belt 31, the discharge roller 42 is simultaneously rotated by a discharge motor (not shown). The document that has been driven to reach the paper discharge inlet sensor 41 is conveyed in the direction of the reverse switching claw 43.

  When performing the reversing operation, the reversing / paper discharging unit 40 drives the reversing switching claw 43 with a reversing solenoid (not shown) in the direction of closing the path toward the reversing path 46, that is, toward the paper ejection outlet roller 45. The original is conveyed on the reverse path 46 along the periphery of the paper discharge roller 42.

  When the trailing edge of the document that has entered the reversing path 46 by the reversing / paper discharging unit 40 reaches the paper discharge inlet sensor 41, the automatic document conveying device 1 further causes the reversing / paper discharging unit 40 to transport the document by a certain amount. After that, the conveyance motor of the conveyance unit 30 is reversely rotated to reverse the conveyance belt 31 in the clockwise direction, come out of the reversing path 46, and contact the document that has come to the reversely-conveying belt 31 portion again in the direction of the document reading position. The glass 61 is conveyed.

  The automatic document feeder 1 conveys a document in the direction of the document reading position. When the leading end of the document at the document reading position reaches the document reading position, the automatic document feeder 1 stops the conveyance motor and conveys the document backward by the conveyance belt 31. To stop.

  When the image reading unit of the image reading device reads the image of the document on the contact glass 61 with the trailing edge of the document set at the document reading position, the automatic document feeder 1 rotates the carry motor forward. The conveying belt 31 is rotated counterclockwise to convey the document to the reversing / paper discharging unit 40.

  When the original is conveyed by the conveyance belt 31, the reversing / paper discharging unit 40 simultaneously rotates the paper discharge roller 42 by a paper discharge motor (not shown) to reverse the original that has reached the paper discharge inlet sensor 41. It is conveyed in the direction of the switching claw 43.

  When the document is discharged, the reversing / paper discharging unit 40 drives the reversing switching claw 43 by a reversing solenoid (not shown) in a direction to open a path toward the paper discharge path 47, that is, toward the paper discharge outlet roller 45. Then, the original is passed through the paper discharge outlet sensor 44 and conveyed to the paper discharge outlet roller 45, and the paper discharge outlet roller 45 discharges the original onto the paper discharge tray 3. At this time, the reverse / discharge unit 40 counts only the sub-scanning length (length) of the document after the trailing edge of the document has passed the discharge outlet sensor 44, and rotates the discharge motor. Then, the document is discharged onto the discharge tray 3 by conveying the document with the discharge outlet roller 45.

  The switchback unit 50 includes a switchback switching claw 51, a switchback sensor (switchback inlet document detection means) 52, a switchback roller 53, a switchback conveyance path 54, and the like. At the time of conveyance, a switchback solenoid (not shown) connected to the switchback switching claw 51 is switched to lower the switchback switching claw 51 and switch to the entry side to the switchback conveyance path 54. In this state, the document conveyed from the conveyance unit 30 to the reversal / sheet discharge unit 40 is sent into the switchback conveyance path 54 by the sheet discharge roller 42 and the switchback roller 53 that are rotationally driven by the sheet discharge motor. Thereafter, the rotation direction of the paper discharge motor is switched, the switchback solenoid is switched, the switchback switching claw 51 is raised and switched to the backward side from the switchback conveyance path 54, and the document is switched back by the switchback roller 53. The paper is discharged from the conveyance path 54 to the paper discharge path 47. The original discharged to the paper discharge path 47 is discharged onto the paper discharge tray 3 by a paper discharge outlet roller 45.

  The switchback sensor 52 is disposed at the entrance of the switchback conveyance path 54, and a reflection type photosensor is used.

  Based on the detection result of the switchback sensor 52 and the detection results of the paper discharge inlet sensor 41 and the paper discharge outlet sensor 44, the automatic document feeder 1 performs a switchback failure jam, a switchback retention jam, The presence / absence of occurrence of a jam at the paper discharge exit and the bellows jam in the switchback transport path 54 is detected.

  Next, the operation of the present embodiment will be described. The automatic document feeder 1 according to the present embodiment is characterized in that it appropriately detects whether or not a jam has occurred during document transportation using the switchback transportation path 54.

  As described above, the automatic document feeder 1 is assembled in an image reading apparatus as a main device such as a copying apparatus, and the image reading apparatus uses the automatic document feeder 1 to perform a copy operation of a plurality of documents. In this case, the user sets a plurality of documents on the document tray 21 of the automatic document feeder 1, and a single-side mode in which only one side of the document is read, a double-sided reading mode in which both sides of the document are read, and documents of different sizes are mixed. A necessary mode setting operation such as a mixed document mode is performed on the operation unit 201 of the image reading apparatus, and then the start key of the operation unit 201 is pressed.

  Now, when a plurality of single-sided originals are set on the original platen 4 and the start key is turned on in the operation unit of the image reading apparatus which is the main body apparatus, the automatic original conveying apparatus 1 reads the single-sided originals on the original table 4. When the calling / separating unit 10 separates the sheets one by one and feeds them to the paper feeding unit 20, the paper feeding unit 20 conveys the original to the original reading position on the contact glass 61, and the conveyance to the original reading position is completed. A document stop signal is transmitted to the reading device.

  When the image reading device receives the document stop signal, the image reading device reads an image of the document at the document reading position, and outputs a paper feed / discharge command to the automatic document feeder 1 when the document reading is completed.

  When the automatic document feeder 1 receives the paper feed / discharge command, the transport unit 30 transports the document to the reverse / discharge unit 40, and the reverse / discharge unit 40 is now a single-sided document. The switchback switching claw 51 is switched by switching a switchback solenoid (not shown) connected to the switchback switching claw 51 in order to carry it back to the switchback conveyance path 54 without sending it back onto the contact glass 61. Is switched to the entry side to the switchback conveyance path 54. In this state, the document conveyed from the conveyance unit 30 to the reversal / sheet discharge unit 40 is sent into the switchback conveyance path 54 by the sheet discharge roller 42 and the switchback roller 53 that are rotationally driven by the sheet discharge motor. Thereafter, the rotation direction of the paper discharge motor is switched, the switchback solenoid is switched, the switchback switching claw 51 is raised and switched to the backward side from the switchback conveyance path 54, and the document is switched back by the switchback roller 53. The paper is discharged from the conveyance path 54 to the paper discharge path 47. The original discharged to the paper discharge path 47 is discharged onto the paper discharge tray 3 by a paper discharge outlet roller 45.

  Then, the automatic document feeder 1 switches the switch based on the detection result of the switchback sensor 52 and the detection results of the paper discharge inlet sensor 41 and the paper discharge outlet sensor 44 in this series of document transport operations, as will be described later. The presence or absence of occurrence of back unreachable jam, switchback retention jam, paper discharge outlet unreachable jam, and bellows jam in the switchback transport path 54 is detected.

  That is, if the switchback sensor 52 does not detect the presence of a document even after a certain period of time has elapsed after the discharge entrance sensor 41 detects that there is a document, the automatic document feeder 1 determines that the switchback has not reached, The image reading device is notified of the occurrence of the switchback unachieved jam, and the image reading device displays the occurrence of the switchback unreached jam on the display or the like of the operation unit, thereby notifying the user.

  The automatic document feeder 1 also enters the switchback conveyance path 54 when the switchback sensor 52 does not detect the absence of a document even after a certain period of time has elapsed after the switchback sensor 52 detects the presence of a document. It is determined that a switchback retention jam that prevents the fed document from being discharged has occurred, notifies the image reading device of the occurrence of the switchback retention jam, and the image reading device generates a switchback retention jam on the display of the operation unit. Is displayed to the user.

  Furthermore, the automatic document feeder 1 is sent out from the switchback conveyance path 54 if the discharge outlet sensor 44 does not detect the presence of a document even after a certain time has elapsed after the switchback sensor 52 detects that there is no document. It is determined that the original does not reach the mouth sensor 44 due to paper discharge, and the paper discharge outlet has not reached the jam. The user is notified by displaying the occurrence of a paper exit unachieved jam.

  Further, the occurrence of bellows jam that causes deformation of the document in the switchback conveyance path 54 is detected from the detection result of the presence / absence of the document by the switchback sensor 52, and the image reading apparatus is notified of the occurrence of the bellows jam. The reading device displays the occurrence of bellows jam on the display or the like of the operation unit to notify the user.

  On the other hand, the automatic document feeder 1 discharges a document without switching back by the switchback unit 50 when the document is ejected when the document is reversed and read on both sides.

  That is, when the automatic document feeder 1 reads the front and back surfaces of a double-sided document by inverting the document, first, the automatic document feeder 1 first sets the document surface at the document reading position of the contact glass 61 with the contact glass 61 side facing. Is completed, the original is transported from the transport unit 30 to the reversing / paper discharging unit 40, and the reversing / paper discharging unit 40 uses a reversing switching claw 43 with a reversing solenoid (not shown) to the reversing path 46 side, Then, the paper is driven in a direction to close the passage toward the paper discharge roller 45, and the document conveyed from the conveyance unit 30 is conveyed on the reverse path 46 along the periphery of the paper discharge roller 42.

  When the trailing edge of the document that has entered the reversing path 46 by the reversing / paper discharging unit 40 reaches the paper discharge inlet sensor 41, the automatic document conveying device 1 further causes the reversing / paper discharging unit 40 to transport the document by a certain amount. After that, the conveyance motor of the conveyance unit 30 is reversely rotated to reverse the conveyance belt 31 in the clockwise direction. The contact glass 61 is conveyed in the position direction.

  The automatic document feeder 1 conveys a document in the direction of the document reading position. When the leading end of the document at the document reading position reaches the document reading position, the automatic document feeder 1 stops the conveyance motor and conveys the document backward by the conveyance belt 31. To stop.

  When the image reading unit of the image reading device reads the image of the document on the contact glass 61 with the trailing edge of the document set at the document reading position, the automatic document feeder 1 rotates the carry motor forward. The conveying belt 31 is rotated counterclockwise to convey the document to the reversing / paper discharging unit 40.

  When the original is conveyed by the conveyance belt 31, the reversing / paper discharging unit 40 simultaneously rotates the paper discharge roller 42 by a paper discharge motor (not shown) to reverse the original that has reached the paper discharge inlet sensor 41. It is conveyed in the direction of the switching claw 43.

  The reverse / discharge unit 40 drives the reverse switching claw 43 in a direction to open the passage toward the discharge path 47, that is, toward the discharge outlet roller 45, by a reverse solenoid (not shown) in order to discharge a double-sided document. Then, the original is passed through the paper discharge outlet sensor 44 and conveyed to the paper discharge outlet roller 45, and the paper discharge outlet roller 45 discharges the original onto the paper discharge tray 3.

  Therefore, in the case of a double-sided document, the automatic document feeder 1 can ignore the detection information of the switchback sensor 52 and prevent erroneous detection based on the switchback sensor 52 and erroneous detection.

  As described above, the automatic document feeder 1 according to the present embodiment separates a plurality of documents on the document table 4 one by one and conveys them to the document reading position on the contact glass 61 to complete the image reading. The original at the original reading position is temporarily stored in the switchback conveyance path 54 of the switchback unit 50 via the reversing / discharge unit 40, then turned back and sent in the paper discharge direction, and sent out from the switchback unit 50. When the reversed document is discharged onto the discharge tray 3 by the reversing / discharging unit 40, the original conveyed at the entrance of the reversing / discharging unit 40 from the contact glass 61 to the reversing / discharging unit 40 is removed. A switch from the reversing / paper discharge unit 40 based on the detection results of the paper discharge inlet sensor 41 to be detected and the switchback sensor 52 provided at the inlet of the switchback conveyance path 54 to detect the presence or absence of a document. The unreachable jam due to the unsuccessful arrival of the document transported to the backpack transport path 54 to the switchback transport path 54 is detected, and the document stays in the switchback transport path 54 based on the detection result of the switchback sensor 52. A paper discharge outlet for detecting a jammed jam and a bellows jam due to a deformation of the original in the switchback conveyance path 54 and detecting a document discharged onto the discharge tray 3 by the switchback sensor 52 and the reverse / discharge unit 40. Based on the detection result of the sensor 44, an unreached jam due to the reversal of the original conveyed from the switchback conveyance path 54 to the paper discharge unit 40 and the failure to reach the paper discharge unit 40 is detected.

  Accordingly, not only the bellows jam in which the document is deformed in the switchback transport path 54, but also the unreachable jam in the switchback transport path 54 in which the document is not deformed, the staying jam in the switchback transport path 54, and the discharge tray 3 side. The unreached jam can be detected, and proper conveyance of the original can be ensured to improve usability.

  In the automatic document feeder 1 of this embodiment, at least the switchback sensor 52 is a reflection type photosensor.

  Therefore, not only the bellows jam but also the unreached jam to the switchback transport path 54 where the original is not deformed, the stay jam in the switchback transport path 54 and the unreachable jam to the discharge tray 3 side can be easily and inexpensively performed. Thus, it is possible to reliably and inexpensively ensure proper conveyance of the original document, making the automatic document conveying apparatus 1 inexpensive, and further improving the usability.

  Furthermore, the automatic conveyance apparatus 1 according to the present embodiment, when conveying a document, does not pass through the switchback conveyance path 54 and discharges the document from the conveyance / discharge unit 40 onto the discharge tray 3. The detection result of the switchback sensor 52 is ignored.

  Therefore, it is possible to prevent erroneous detection of the switchback sensor 52, prevent malfunction due to erroneous detection of the switchback sensor 52, and further improve the usability.

  In addition, the automatic document feeder 1 of the present embodiment includes a reversing / paper discharging unit 40 that reverses the original transported from the transporting unit 30 and returns it to the transporting unit 30, and the transporting unit 30 performs the reversing / paper discharging. When the document reversed by the unit 40 is transported to the document reading position on the contact glass 61 again, after the reading of the document reversed by the reversing / paper discharging unit 40 is completed in the conveyance of the double-sided document, the document is When the paper is discharged from the reversing / paper discharge unit 40 onto the paper discharge tray 3, the detection result of the switchback sensor 52 is ignored.

  Therefore, in the conveyance of a double-sided document in which the document is discharged without using the switchback unit 50, the detection result of the switchback sensor 52 is ignored to prevent erroneous detection of the switchback sensor 52. A malfunction due to erroneous detection can be prevented, and usability can be further improved.

  The invention made by the present inventor has been specifically described based on the preferred embodiments. However, the present invention is not limited to the above, and various modifications can be made without departing from the scope of the invention. Needless to say.

  It is mounted on image reading devices such as scanners, facsimile machines, and copying machines, and it improves the usability by accurately detecting the presence or absence of jamming of the original when the original is switched back using the switchback unit. It can be applied to an automatic document feeder.

1 is a schematic front view of an automatic document feeder to which one embodiment of an automatic document feeder of the present invention is applied. FIG. 2 is an enlarged front view of a reverse / paper discharge unit and a switchback unit of the automatic document feeder of FIG. 1.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Automatic document conveying apparatus 2 Housing | casing 3 Paper discharge tray 4 Document stand 10 Calling / separating part 11 Calling roller 12 Separating roller 20 Paper feeding part 21 Pull-out sensor 22 Paper feeding roller 23 Registration sensor 30 Conveying part 31 Conveying belt 32 Conveying roller 33 Roller 40 Reverse / discharge section 41 Discharge entrance sensor 42 Discharge roller 43 Reverse switching claw 44 Discharge exit sensor 45 Discharge exit roller 46 Reverse path 47 Discharge path 50 Switchback section 51 Switchback switching claw 52 Switchback sensor 53 Switchback roller 54 Switchback transport path 61 Contact glass

Claims (4)

  A plurality of documents on the document table are separated one by one and conveyed to the document reading position on the contact glass, and the document at the document reading position where the image reading is completed is temporarily switched via the paper discharge unit. In the automatic document feeder, the document is fed back from the switchback unit after being stored in the switchback conveyance path of the back unit and sent out in the paper discharge direction. A paper discharge entrance original detection means for detecting a document conveyed to the paper discharge portion from the contact glass provided at the paper discharge portion entrance, and a switchback provided at the switchback conveyance path entrance for detecting the presence or absence of the original. An entrance document detection means and a delivery document detection means for detecting a document ejected on the delivery table by the delivery section are provided, and the delivery entrance document detection means and the switch are provided. Based on the detection result of the back entrance document detection means, an unreachable jam due to the failure of the document transported from the paper discharge unit to the switchback transport path to the switchback transport path is detected, and the switchback entrance document detection is performed. Based on the detection result of the means, a stay jam in the document in the switchback conveyance path and a bellows jam due to a deformation of the document in the switchback conveyance path are detected, and the switchback inlet detection means and the discharged document detection An automatic document feeder which detects an unreached jam due to unsuccessful delivery of a document conveyed from the switchback conveyance path to the paper discharge unit based on a detection result of the means.   2. The automatic document feeder according to claim 1, wherein at least the switchback entrance document detection means is a reflection type photosensor.   The automatic document feeder detects the switchback entrance document when the document is ejected from the delivery unit onto the delivery table without passing through the switchback delivery path. 3. The automatic document feeder according to claim 1, wherein the detection result of the means is ignored. The automatic document conveying device further includes a reversing unit that reverses the document conveyed from the conveying unit and returns the document to the conveying unit, and the conveying unit again converts the document reversed by the reversing unit to the contact glass. An automatic document feeder that transports the document to the document reading position above, wherein the document is a double-sided document, and after the document that has been reversed by the reversing unit in the conveyance of the document is read, 3. The automatic document feeder according to claim 1, wherein when the paper is discharged from the paper discharge unit onto the paper discharge table, the detection result of the switchback entrance original detection unit is ignored.

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