JP5533286B2 - Automatic document feeder and image forming apparatus - Google Patents

Description

  The present invention is a so-called sheet that reads a document image by taking in the reflected light of the light irradiated on the document passing through the slit glass while the optical system mounted on the image reading apparatus is stopped below the slit glass shorter than the document. The present invention relates to a through-type automatic document feeder and an image forming apparatus including the same.

  Conventionally, when reading a plurality of front and back double-side originals in an image reading apparatus provided in an image forming apparatus such as a copying apparatus, generally, the same is obtained by first reversing the original after reading the surface of the original at the reading position. Although the back side is read at the reading position, the orientation of the original is opposite to the original reading direction and the order of the originals is reversed. Therefore, the original is reversed and read again to match the order after the back side is read. Passing position. As described above, in the conventional image forming apparatus, since the document is transported to the reading position only for adjusting the order of the documents, a reading operation cannot be performed during that time, and it takes time to read a plurality of documents continuously. There was a problem that productivity deteriorated.

  For this reason, for example, Patent Document 1 discloses a technique that provides a conveyance path for reversing the order after reading the back side of a double-sided document so that the next document can be read even during the reversal operation of the order. Yes. Also, a tray for single-sided originals and a tray for double-sided originals are provided to read from the topmost document in the bundle of originals placed on one side and from the bottommost document in the bundle of originals placed on both sides. Thus, for example, “Patent Document 2” discloses a technique for aligning the order of originals without being reversed again after reading the back side of a double-sided original. Furthermore, there is a technology that reads from the lowest document in the bundle of documents placed on the tray and changes the output destination for single-sided and double-sided originals so that the order of the originals can be adjusted without re-inversion after reading the back side of double-sided originals. For example, it is disclosed in “Patent Document 3”.

  In the technique disclosed in “Patent Document 1”, there is a problem that the apparatus becomes large because a conveyance path is provided only for reversing the original after reading the back side of the double-sided original for alignment, If the conveyance path is stored in a small space in order to prevent an increase in size, the shape of the conveyance path becomes tight, and there is a problem in that conveyance defects such as paper jams and document damage occur. In the technique disclosed in “Patent Document 2”, the apparatus is enlarged because two document trays for a single-sided document and a double-sided document are provided, and the conveyance direction at the reading position is reversed between the single-sided document and the double-sided document. Therefore, design restrictions such as the setting of the conveyance speed and the shape of the reading unit increase, and there is a possibility that a good image cannot be obtained. Further, since the setting position is different between the single-sided original and the double-sided original, a setting error by the user is likely to occur. The technique disclosed in “Patent Document 3” has a problem that the apparatus becomes large because two discharge trays for single-sided originals and double-sided originals are provided.

  SUMMARY OF THE INVENTION The present invention solves the above-described problems, and a sheet-through type automatic document conveying apparatus capable of continuously and efficiently reading double-sided originals and increasing the productivity by configuring the apparatus in a compact and inexpensive manner. An object of the present invention is to provide an image forming apparatus provided with this.

According to the first aspect of the present invention, there is provided a document tray on which a bundle of documents can be placed, a sheet feeding means for feeding several documents from the document bundle on the document tray, and the fed documents one by one. Separating means for separating and feeding; conveying means for conveying the separated and fed document to the reading position; discharging means for discharging the document read at the reading position; and discharging paper on which the discharged document is placed In an automatic document feeder having a paper tray and a reversing unit that reverses a document read at the reading position and then transports the document to the reading position again, the paper feeding unit is placed on the document tray. An upper sheet feeding unit that feeds several documents from the uppermost side of the document bundle, and a lower sheet feeding unit that feeds several documents from the lowermost side, and the separating unit is the upper sheet feeding unit The upper separating means for separating and feeding the document fed by the above and the lower feeding means A lower separation unit that separates and feeds the paper document, and separates and feeds one original document to the conveying unit by the upper feeding unit and the upper separation unit when reading one-sided document, and lowering when reading a two-sided document. One original is separated and fed to the conveying means by the paper means and the lower separating means, and the upper separating means and the lower separating means are each composed of a pair of freely contactable and separable rollers, and the upper feeding means and the lower feeding means The paper means and the upper separating means and the lower separating means are provided on the same document transport path, and when the document is fed by the upper feeding means, the roller pair of the lower separating means is separated from each other, When the document is fed by the lower sheet feeding unit, the roller pair of the upper separating unit is separated from each other .

According to a second aspect of the present invention, there is provided a document tray on which a bundle of documents can be placed, a sheet feeding means for feeding several documents from the document bundle on the document tray, and the fed documents one by one. Separating means for separating and feeding; conveying means for conveying the separated and fed document to the reading position; discharging means for discharging the document read at the reading position; and discharging paper on which the discharged document is placed In an automatic document feeder having a paper tray and a reversing unit that reverses a document read at the reading position and then transports the document to the reading position again, the paper feeding unit is placed on the document tray. An upper sheet feeding unit that feeds several documents from the uppermost side of the document bundle, and a lower sheet feeding unit that feeds several documents from the lowermost side, and the separating unit is the upper sheet feeding unit The upper separating means for separating and feeding the document fed by the above and the lower feeding means A lower separation unit that separates and feeds the paper document, and separates and feeds one original document to the conveying unit by the upper feeding unit and the upper separation unit when reading one-sided document, and lowering when reading a two-sided document. A positioning member that positions and feeds a downstream end of the bundle of documents placed on the document tray in a conveying direction by separating and feeding one document to the conveying unit by a paper unit and a lower separating unit; The lower separation unit is constituted by a sheet feeding unit and the positioning member .

The invention described in claim 3 is an image forming apparatus having the automatic document feeder according to claim 1 or 2 .

According to a fourth aspect of the present invention, in the image forming apparatus according to the third aspect, when image formation based on a double-sided original is further performed, the images are formed in the order in which the double-sided original is read .

According to a fifth aspect of the present invention, in the image forming apparatus according to the third or fourth aspect, the image forming apparatus further includes a post-processing device that performs stapling or paper folding, and any post-processing is performed together with image formation of a double-sided document. Is characterized in that a double-sided original is fed and read by the upper paper feed means, and is reversely conveyed to match the order of the originals after the double-sided reading is completed .

  According to the present invention, when reading a double-sided document, it is possible to match the front and back and the order of the documents discharged on the discharge tray without re-inverting the document after reading the back side with the state of being stacked on the document tray. By completing the image forming operation without performing the document reversing operation for order matching, it is possible to significantly improve the working efficiency at the time of double-sided document reading.

1 is a schematic front view of an image forming apparatus to which an embodiment of the present invention can be applied. 1 is a schematic front view of a main part of an image forming apparatus to which an embodiment of the present invention can be applied. 1 is a schematic front view of an automatic document feeder that employs a first embodiment of the present invention. FIG. 6 is a schematic front view of an automatic document feeder that employs a second embodiment of the present invention. It is a schematic front view of the automatic document feeder which employ | adopted the 3rd Embodiment of this invention.

  FIG. 1 shows an image forming apparatus to which an embodiment of the present invention can be applied. In the figure, an image forming apparatus 200 has a sheet-through type automatic document feeder 100 capable of reading a double-sided document at the top of the apparatus body. In the automatic document feeder 100, a document tray 1 on which a bundle of documents P1 made up of a plurality of documents can be placed is arranged at the upper part, and a discharge tray 8 for discharging the read document is disposed below the document tray 1. It is arranged.

  On the upper surface of the document tray 1, a side fence 2 for restricting the position in the width direction, which is a direction orthogonal to the document conveyance direction, and a document stopper 3 for regulating the position in the document conveyance direction are provided. A pickup roller 11 is disposed on the upstream side of the document stopper 3 in the document conveyance direction, and a feed roller 12 is disposed on the downstream side of the document stopper 3. The pickup roller 11 is separated at a position facing the feed roller 12 via the document conveyance path. A member 4 is provided. A pull-out roller 13 is disposed downstream of the feed roller 12 in the document conveyance direction, and a pre-reading roller 14 is disposed further downstream. A white background plate 5 is disposed on the downstream side of the pre-reading roller 14 in the original conveyance direction, and a very narrow original conveyance path is formed between the white background plate 5 and the contact glass 6 disposed opposite thereto. A document reading position 22 is set on the top. A paper discharge roller 15 is disposed downstream of the document reading position 22 in the document transport direction, and a reversing roller 16 is disposed further downstream. A branch claw is disposed between the paper discharge roller 15 and the reversing roller 16. 7 is disposed. Above the paper discharge roller 15, a reverse conveyance path is formed for conveying the document reversely conveyed by the reverse roller 16 directly to the pre-reading roller 14.

  Next, the operation of the automatic document apparatus 100 will be described. First, the end of the original bundle P1 is abutted against the original stopper 3 to perform positioning in the transport direction, and then the side fence 2 is used to perform positioning in the width direction to set the original bundle P1 on the original tray 1. When a start key (not shown) of the image forming apparatus 200 is pressed, several pickups are fed to the feed roller 12 by rotating after the pickup roller 11 comes into contact with the upper surface of the document bundle P1, and the feed roller 12 The uppermost document is separated and fed by the action of the conveying force and the return force due to the frictional resistance of the separating member 4.

  The separately fed document is transported by the white background plate 5 and the contact glass 6 in a state reversed from that when the document is set on the document tray 1 via the pull-out roller 13 and the pre-reading roller 14. The image is conveyed to the path, conveyed while being read at the document reading position 22 by the reading unit 41 disposed below the contact glass 6, and conveyed to the paper discharge roller 15. When reading a single-sided document, since the document has already been read at this point, the document conveyed by the sheet discharge roller 15 is guided to the sheet discharge tray 8 by the branch claw 7 and discharged. At this time, the orientation of the document is reversed from that when it is set on the document tray 1, but the next document is discharged so as to overlap the previous document, so that it is stacked on the document tray 1. The sheets are stacked on the paper discharge tray 8 in the same order as they were.

  On the other hand, when reading a double-sided document, the image on the back side is further read, so that the document conveyed by the paper discharge roller 15 is guided to the branching claw 7 and sent to the reverse roller 16. The reversing roller 16 rotates backward after being temporarily stopped while holding the rear end (right end in FIG. 1) of the document, and the document is guided by the moved branching claw 7 and sent to the reversing conveyance path. The document sent to the reverse conveyance path reaches the pre-reading roller 14 and is conveyed to the conveyance path formed by the white background plate 5 and the contact glass 6 in a state where the front and back are reversed. In 41, the back image is read. At this time, the image reading of the double-sided original is completed. At this time, since the original is set in the same direction (front and back) on the original tray 1, the next original is discharged so as to overlap the previous original. As a result, the order of the originals is different from the state in which the originals are stacked on the original tray 1. For this reason, in order to match the order of the originals, the original after the double-sided image reading is sent again to the reverse roller 16, and the original is sent again to the reverse conveyance path to be reversed on the front and back and discharged onto the paper discharge tray 8.

  Next, the configuration and operation of the image forming apparatus 200 will be described. In the lower part of the image forming apparatus 200, paper feed cassettes 51 and 52 that can store transfer papers of different sizes are arranged, and the transfer paper stored in the paper feed cassettes 51 and 52 is called. After being fed by the rollers 51a and 52a, the paper is separated and fed by the paper feed rollers 51b and 52b and the reverse rollers 51c and 52c that are slidably contacted with the rollers 51a and 52b and can rotate in the direction opposite to the paper transport direction. The separated and fed transfer paper is conveyed to the registration roller pair 55 via the relay rollers 53 and 54, and timed by the registration roller pair 55 to the conveyance path between the photosensitive drum 43 and the transfer belt 47. Be transported.

  The reading unit 41 provided on the upper part of the apparatus main body includes a light source, a reflection mirror, a condensing lens, an image sensor such as a CCD, and the like. Image information read by the reading unit 41 is photosensitized from the writing unit 42. The surface of the body drum 43 is exposed to light. Around the photosensitive drum 43, as shown in FIG. 2, a charging device 44, a potential sensor 45, a developing device 46, a transfer belt 47, a cleaning device 48, a static eliminator 49, and the like that form an image forming unit together with the photosensitive drum 43. Is arranged. The charging device 44 is configured to charge the surface of the photosensitive drum 43 to a constant potential by controlling a positive corona discharge with a grid in the dark. The writing unit 42 irradiates a laser diode containing image information onto the photosensitive drum 43 charged to a constant potential, and removes negative charges on the photosensitive drum 43 to form an electrostatic latent image. The potential sensor 45 measures the potential on the photosensitive drum 43 and corrects it by process control. The developing device 46 forms a visible image by attaching a negatively charged toner to a portion from which the charge has been removed on the photosensitive drum 43. A positive bias is applied to the transfer belt 47, and a negatively charged visible image is transferred to a transfer sheet and conveyed. The cleaning device 48 includes a cleaning blade, and scrapes off the toner remaining on the photosensitive drum 43. The static eliminator 49 turns on the LED to remove the residual charge on the photosensitive drum 43 and prepares for image formation on the next transfer sheet.

  The transfer paper conveyed to the conveyance path between the photosensitive drum 43 and the transfer belt 47 and having the toner image on the photosensitive drum 43 transferred thereon is conveyed to the fixing device 50 and the toner image is fixed. At the time of single-sided printing, the transfer paper is sent to the conveyance path 61 after fixing and discharged onto the paper discharge tray 65 with the print side down. On the other hand, at the time of duplex printing, the image on the back side is first fixed until the duplex reading of the original is completed, and then the transfer sheet conveyed to the conveyance path 62 is switched back and sent to the conveyance path 63. The transfer sheet sent to the conveyance path 63 is conveyed again between the photosensitive drum 43 and the transfer belt 47 via the relay roller 54 and the registration roller pair 55, and the surface image is transferred. After the transfer of the front image, the transfer paper is sent to the fixing device 50 and fixed, and then discharged onto the paper discharge tray 65 via the transport path 61 with the front image being faced down.

  In the image forming apparatus 200 described above, when a double-sided original is read by the automatic document feeder 100, the original after double-sided reading is sent again to the reversing roller 16 for order alignment, and the paper discharge tray 8 is turned upside down. It is discharging to the top. For this reason, as described in the “Background Art” column, the reading operation cannot be performed while the originals are being conveyed for ordering. There is a problem that it takes a lot of time and productivity deteriorates. An embodiment of the present invention that solves this problem will be described below.

  In FIG. 3 showing the first embodiment of the present invention, an automatic document feeder 30 has a document tray 31 on which a document bundle P1 is placed, and an upper surface of the document tray 31 in the width direction of the document bundle P1. A side fence 32 for restricting the set position is provided, and a document stopper 33 as a positioning member for restricting the set position in the transport direction of the document bundle P1 is provided at the downstream end of the document transport direction. The lower end of the document stopper 33 is rotatably supported by the document tray 31 and is rotated by a driving means (not shown). The document stopper 33 stands vertically and restricts the document bundle P1, and a horizontal position in FIG. The position where the document is fed and the feeding position indicated by the two-dotted line is selectively occupied.

  An upper pickup serving as an upper paper feed unit that is in contact with the upper surface of the document bundle P1 and feeds the document from its uppermost side above the document tray 31 and upstream of the document stopper 33 in the document transport direction. A roller 34 is provided. The upper pickup roller 34 is rotatably supported by a support member 35 and is rotationally driven by a driving means (not shown). The support member 35 supports the upper pickup roller 34 at one end side, and is configured to be swingable with the other end side as a fulcrum. The support member 35 is swung by a swinging means (not shown), and the upper pick-up roller 34 is configured to be able to contact and separate from the uppermost document in the document bundle P1. At a position facing the upper pickup roller 34 via the document bundle P1, a lower pickup roller 36 is disposed as a lower sheet feeding means that contacts the lower surface of the document bundle P1 and feeds the document from its lowest side. ing. The lower pickup roller 36 is rotatably supported on the document tray 31 and is driven to rotate by a driving unit (not shown).

  On the downstream side of the document stopper 33 in the document conveyance direction, a conveyance path 37 is formed through which the document fed from the document bundle P1 by the upper pickup roller 34 or the lower pickup roller 36 is conveyed. At the upstream position, an upper separating means 38 for separating and feeding the documents fed by the upper pickup roller 34 one by one is disposed. The upper separating means 38 is rotatably supported by the support member 35 and is rotationally driven by a drive means (not shown), and the upper feed roller 38a is rotatably supported by a support member (not shown) and contacted / separated means (not shown). It is comprised by the roller pair which consists of the upper separation roller 38b comprised so that contact / separation was possible. The upper separation roller 38b rotates following the contact with the upper feed roller 38a. A lower separation unit 39 for separating and feeding the documents fed by the lower pickup roller 36 one by one is disposed downstream of the upper separation unit 38 in the document conveyance direction. The lower separation means 39 is rotatably supported by a side plate (not shown) and is rotated by a driving means (not shown), and the lower feed roller 39a is rotatably supported by a support member (not shown) and contact / separation means (not shown). It is comprised by the roller pair which consists of the lower separation roller 39b comprised so that contact / separation was possible. The lower separation roller 39b is driven to rotate while in contact with the lower feed roller 39a.

  A pull-out roller 40, a pre-reading roller 25 serving as a transport unit, a paper discharge roller 26 serving as a paper discharge unit, and a reverse roller 27 serving as a reverse unit capable of rotating forward and backward are arranged in this order on the downstream side of the lower separation unit 39 in the original transport direction. A reading path formed by the white background plate 23 and the contact glass 24 is provided between the paper discharge roller 26 and the reverse roller 27 between the pre-reading roller 25 and the paper discharge roller 26. Is provided with a reversing path 29 connected to the pre-reading roller 25 on the left side of the paper discharge roller 26. The branch claw 28 is swung by a swinging means (not shown) and selectively occupies a normal position indicated by a solid line and a double-sided position indicated by a two-point difference line in FIG. Below the document tray 31, a paper discharge tray 19 for discharging a document on which an image has been read is provided, and a document reading position 20 is set on the reading path.

  The operation of the automatic document feeder 30 will be described below. When N double-sided original bundle P1 is set on original tray 31 and double-sided scanning is designated, when a start key (not shown) of image forming apparatus 200 is pressed, original stopper 33 moves to the feeding position and lowers. The pickup roller 36 rotates and a small number of documents including the lowest document of the document bundle P1 are fed. At this time, the upper feed roller 38 a and the upper separation roller 38 b are in a separated state, and the fed document is sent to the lower separation means 39. The lower feed roller 39a and the lower separation roller 39b are in contact with each other, the originals sent to the lower separation means 39 are separated one by one, and only the lowest Nth original is conveyed further downstream. Is done.

  The transported Nth document is transported to the reading path in a state reversed from the state of being placed on the document tray 31 by the pull-out roller 40 and the pre-reading roller 25. The image can be read. The Nth original from which the front image has been read is conveyed to the right in FIG. 3 by the paper discharge roller 26, guided by the branching claw 28 occupying the double-sided position, and conveyed to the reverse roller 27. The document is conveyed rightward in FIG. 3 by the rotation of the reverse roller 27, and when the left end of the document passes through the paper discharge roller 26, the rotation of the reverse roller 27 is temporarily stopped. Thereafter, when the branching claw 28 is displaced to the normal position, the reversing roller 27 rotates in the opposite direction, and the document is sent to the reversing path 29 and is conveyed to the reading path by the pre-reading roller 25 and is placed on the document tray 31. The back side image is read at the original reading position 20 in the same state as the placed state. The Nth document whose back side image has been read is discharged onto the discharge tray 19 in the same state as the state where the front surface is turned up by the discharge roller 26, that is, the state where it is placed on the document tray 31. . Next, the (N-1) th original is read on both sides in the same manner as the Nth original and then discharged onto the paper discharge tray 19 so as to overlap the Nth original. . Thereafter, when the same operation is repeated to complete the reading of N double-sided originals, the uppermost original is the first original and the lowest original is N sheets of the double-sided original bundle P1 discharged onto the paper output tray 19. All the eyes are in a state where the surface is directed upward, and both the front and back sides and the order are the same as those placed on the document tray 31. In the order in which the double-sided original reading operation is completed, the image forming apparatus 200 performs the same image forming operation as described above based on the N-th to the first double-sided originals.

  On the other hand, when N single-sided document bundles P1 are set on the document tray 31 and single-side reading is designated, when a start key (not shown) of the image forming apparatus 200 is pressed, the document stopper 33 moves to the feeding position. At the same time, the upper pickup roller 34 rotates to feed a small number of documents including the uppermost document in the document bundle P1. At this time, the lower feed roller 39a and the lower separation roller 39b are in a separated state, and the fed document is sent to the upper separation means 38. The upper feed roller 38a and the upper separation roller 38b are in contact with each other, the originals sent to the upper separation unit 38 are separated one by one, and only the uppermost first original is conveyed further downstream. Is done. Thereafter, the image reading is performed in the same manner as in the automatic document feeder 100 described above, and the single-sided document bundle P1 discharged onto the paper discharge tray 19 is the first lowest document and the Nth highest document. All are in a state in which the back surface faces upward, and the order is the same as the state in which the back surface is placed on the document tray 31, and the front and back surfaces and the top and bottom are reversed.

  According to the above configuration, when reading a double-sided document, the front and back sides and the order of the documents discharged onto the discharge tray can be matched with the state of being stacked on the document tray without re-inverting the document after reading the back side. By completing the image forming operation without performing the document reversing operation for order matching, it is possible to significantly improve the working efficiency when reading a double-sided document. Further, since the upper separation means 38 and the lower separation means 39 are provided on the same transport path, the apparatus can be miniaturized. Furthermore, since each roller pair which comprises the upper separation means 38 and the lower separation means 39 contacts / separates as needed, reliable separation feeding can be performed. In addition, when performing image formation based on a double-sided original, the image forming operation is performed in the order in which the double-sided original is read. Therefore, the order of the transfer sheets on which the images are formed can be matched with the order of the originals. The work efficiency of the image forming operation can be improved.

  FIG. 4 shows an automatic document feeder 70 adopting the second embodiment of the present invention. Hereinafter, the automatic document feeder 70 will be described. The same components as those of the automatic document feeder 30 shown in the first embodiment are denoted by the same reference numerals, and detailed descriptions thereof are omitted.

  A document stopper 71 serving as a positioning member for regulating the set position of the document bundle P1 in the transport direction is disposed at the downstream end of the document tray 31 in the document transport direction. The lower end of the document stopper 71 is rotatably supported by the document tray 31 and is rotated by a driving means (not shown) so that the document stopper 71 stands vertically and restricts the document bundle P1. The upper separation feeding position indicated by a two-dotted line in the figure that allows the document to be fed to the upper separation feeding path 72 and the feeding to the lower separation feeding path 73 that is located obliquely. Is selectively occupied with the lower separation feeding position indicated by the alternate long and short dash line in FIG.

  On the downstream side of the document stopper 71 in the document transport direction, the upper pickup roller 34 feeds the document fed from the document bundle P1 and the lower pickup roller 36 feeds the document bundle P1 from the document bundle P1. A lower separation feeding path 73 for conveying the original is formed, and is rotatably supported by a side plate (not shown) at a position between the separation feeding paths 72 and 73 and is rotated forward and backward by a driving means (not shown). A driving roller 74 is disposed. The drive roller 74 is disposed in a manner in which a part of its peripheral surface is desired in each of the separate feed paths 72 and 73, and the lower driven roller 75 is in contact with the drive roller 74 in the upper separate feed path 72. However, the upper driven roller 76 is disposed in the lower separation feed path 73 so as to come into contact with the driving roller 74. The upper driven roller 75 is rotatably supported by a support member (not shown), and the lower driven roller 76 is rotatably supported by the support member 35 and is pressed against the drive roller 74 by an urging means (not shown). The drive roller 74 is rotationally driven. At this time, the driven rollers 75 and 76 are driven to rotate. The driving roller 74 and the lower driven roller 75 constitute an upper separating means 77, and the driving roller 74 and the upper driven roller 76 constitute a lower separating means 78.

  Based on the above configuration, the operation of the automatic document feeder 70 will be described below. When N double-sided original bundle P1 is set on original tray 31 and double-sided scanning is designated, when a start key (not shown) of image forming apparatus 200 is pressed, original stopper 71 moves to the lower separation feeding position. The lower pickup roller 36 rotates, and a small number of documents including the lowest document in the document bundle P1 are fed to the lower separation feeding path 73. At this time, the driving roller 74 is driven to rotate counterclockwise in FIG. 4, and the originals sent to the lower separation feeding path 73 are separated one by one by the lower separation means 78, and the lowest N sheets. Only the original of the eye is conveyed further downstream. The conveyed Nth original is read on both sides of the image in the same manner as in the first embodiment, and then discharged onto the paper discharge tray 19.

  On the other hand, when N single-sided document bundles P1 are set on the document tray 31 and single-sided reading is designated, when a start key (not shown) of the image forming apparatus 200 is pressed, the document stopper 71 is moved to the upper separation feeding position. At the same time, the upper pickup roller 34 rotates, and a small number of documents including the uppermost document in the document bundle P 1 are fed to the upper separation feeding path 72. At this time, the driving roller 74 is driven to rotate in the clockwise direction in FIG. 4, and the originals sent to the upper separation feeding path 72 are separated one by one by the upper separation means 77, and the uppermost first sheet Only the original document is conveyed further downstream. The conveyed first document is discharged onto the discharge tray 19 after the image on one side is read in the same manner as in the first embodiment.

  With the above-described configuration, the same operational effects as in the first embodiment can be obtained, and the upper separating means 77 and the lower separating means 78 use a common drive roller 74, so that the number of parts can be reduced and the cost can be reduced. In addition, space saving can be achieved. Further, since the document stopper 71 also serves as a guide member for guiding the document, further cost reduction and space saving can be achieved.

  FIG. 5 shows an automatic document feeder 80 employing the third embodiment of the present invention. Hereinafter, the automatic document feeder 80 will be described. Components similar to those of the automatic document feeder 30 shown in the first embodiment and the automatic document feeder 70 shown in the second embodiment are denoted by the same reference numerals. A detailed description of each is omitted.

  A document stopper 81 serving as a positioning member for regulating the set position of the document bundle P1 in the transport direction is disposed at the downstream end of the document tray 31 in the document transport direction. The upper end of the document stopper 81 is rotatably supported by a side plate (not shown) and is rotated by a driving means (not shown) so as to hang down to regulate the document bundle P1 and to function as a lower separating means. It selectively occupies the restriction position and the upper feed position indicated by a two-dot chain line in the drawing which is lifted horizontally and allows feeding by the upper pickup roller 34. A high frictional resistance member 81 a is provided at the lower end of the document stopper 81, and the high frictional resistance member 81 a and the lower pickup roller 36 constitute a lower separation means 82.

  On the downstream side of the document stopper 81 in the document conveyance direction, an upper separation unit 83 is provided for separating and feeding the documents fed by the upper pickup roller 34 one by one. The upper separation means 83 is supported by the support member 35 rotatably and is driven to rotate by a drive means (not shown), and an upper separation member 83b made of a high friction resistance member configured to be able to contact with and separate from the upper feed roller 83a. It is constituted by. The upper separation member 83b is brought into contact with and separated from the upper feed roller 83a by contact / separation means (not shown).

  Based on the above configuration, the operation of the automatic document feeder 80 will be described below. When N double-sided document bundle P1 is set on document tray 31 and double-sided scanning is designated, when a start key (not shown) of image forming apparatus 200 is pressed, lower pickup roller 36 rotates and the top of document bundle P1 is rotated. A small number of documents including the lower document are fed. At this time, the small number of documents fed by the action of the high frictional resistance member 81a of the document stopper 81 occupying the regulation position is separated one by one, and only the lowest Nth document is further moved downstream. Be transported. Further, at this time, the upper separation member 83b occupies a position separated from the upper feed roller 83a, and the conveyed N-th original is scanned on both sides as in the first embodiment, and then discharged. It is discharged onto the tray 19.

  On the other hand, when N single-sided document bundles P1 are set on the document tray 31 and single-sided scanning is specified, when a start key (not shown) of the image forming apparatus 200 is pressed, the document stopper 81 moves to the upper feeding position. At the same time, the upper pickup roller 34 rotates, and a small number of documents including the uppermost document in the document bundle P1 are fed downstream. At this time, the upper separation member 83b occupies a position where it abuts on the upper feed roller 83a, the originals conveyed to the upper separation means 83 are separated one by one, and only the uppermost first original is further downstream. It is conveyed to. The conveyed first document is discharged onto the discharge tray 19 after the image on one side is read in the same manner as in the first embodiment.

  With the above-described configuration, the same operational effects as in the first embodiment can be obtained, and the lower separation means 82 is configured by the lower pickup roller 36 and the document stopper 81, so that the number of parts can be reduced, and cost reduction and saving can be achieved. Space can be achieved.

  In each of the above-described embodiments, the image forming apparatus 200 is shown as the image forming apparatus on which the automatic document feeders 30, 70, and 80 are mounted. However, the image forming apparatus includes a post-processing device that performs stapling or paper folding. The automatic document feeders 30, 70, and 80 may be mounted on the same. In this case, when any post-processing is performed together with the image formation of the double-sided original, the original is fed by the upper pickup roller 34 to perform reading, and after completion of double-sided reading, the order of the originals is matched. It is desirable to adopt a configuration that performs reverse conveyance. As a result, the orientation and order of the transfer paper can be matched with the time of image formation with a single-sided original, and the occurrence of a problem that the direction of stapling or paper folding is reversed can be prevented.

19 Paper discharge tray 25 Conveying means (roller before reading)
26 Paper discharge means (paper discharge roller)
27 Reversing means (reversing roller)
30, 70, 80 Automatic document feeder 31 Document tray 34 Upper paper feed means (upper pickup roller)
36 Lower paper feeding means (lower pickup roller)
38, 77, 83 Upper separating means 39, 78, 82 Lower separating means 71 Guide member (document stopper)
74 Driving roller 75 Lower driven roller 76 Upper driven roller 81 Positioning member (document stopper)
200 Image forming apparatus P1 Document bundle

JP 2003-2546 A JP 2005-89152 A JP 2008-48375 A

Claims (5)

A document tray on which a bundle of documents can be placed, a sheet feeding unit for feeding several documents from the document bundle on the document tray, a separating unit for separating and feeding the fed documents one by one, A conveying unit that conveys the separately fed document to a reading position; a sheet discharging unit that discharges the document read at the reading position; a paper discharge tray on which the discharged document is placed; and In an automatic document feeder provided with reversing means for reversing the read document and then transporting it again to the reading position,
The paper feeding means includes an upper paper feeding means for feeding several originals from the uppermost side of the original bundle placed on the original tray and a lower paper feeding means for feeding several originals from the lowermost side. The separating means includes an upper separating means for separating and feeding the document fed by the upper feeding means, and a lower separating means for separating and feeding the document fed by the lower feeding means. When reading a single-sided document, the upper sheet feeding unit and the upper separating unit separate and feed one original to the conveying unit. When reading a double-sided document, the lower sheet feeding unit and the lower separating unit convey one sheet. The upper separation means and the lower separation means are each composed of a pair of rollers that can be contacted and separated, and the upper sheet feeding means, the lower sheet feeding means, the upper separation means, and the lower separation means are the same. The original is fed by the upper paper feed means. Rollers of the lower separating means are separated from each other as they are, automatic document feeder when a document is fed by the lower sheet feed means, characterized in that the rollers of the upper separating means for separating from each other apparatus. A document tray on which a bundle of documents can be placed, a sheet feeding unit for feeding several documents from the document bundle on the document tray, a separating unit for separating and feeding the fed documents one by one, A conveying unit that conveys the separately fed document to a reading position; a sheet discharging unit that discharges the document read at the reading position; a paper discharge tray on which the discharged document is placed; and In an automatic document feeder provided with reversing means for reversing the read document and then transporting it again to the reading position,
The paper feeding means includes an upper paper feeding means for feeding several originals from the uppermost side of the original bundle placed on the original tray and a lower paper feeding means for feeding several originals from the lowermost side. The separating means includes an upper separating means for separating and feeding the document fed by the upper feeding means, and a lower separating means for separating and feeding the document fed by the lower feeding means. When reading a single-sided document, the upper sheet feeding unit and the upper separating unit separate and feed one original to the conveying unit. When reading a double-sided document, the lower sheet feeding unit and the lower separating unit convey one sheet. A positioning member for positioning and feeding the downstream end of the bundle of documents placed on the document tray in the transport direction, and the lower separation unit is configured by the lower sheet feeding unit and the positioning member automatic document feeder, characterized in that it is. An image forming apparatus comprising the automatic document feeder according to claim 1. The image forming apparatus according to claim 3.
An image forming apparatus, wherein when forming an image based on a double-sided document, the image is formed in the order in which the double-sided document is read. The image forming apparatus according to claim 3 or 4, wherein:
When a post-processing device that performs stapling or paper folding is provided and any post-processing is performed together with image formation of a double-sided original, the double-sided original is fed by the upper paper feeding means to perform reading, and double-sided reading is performed. An image forming apparatus that performs reverse conveyance to match the order of documents after completion.

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