JP2008169026A - Automatic document feeder and document reading device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent damage to documents 3 by preventing serious jamming of the documents 3 due to an erroneous feeding of a separating roller 31, and to prevent reading efficiency from being excessively lowered, in an automatic document feeder. <P>SOLUTION: This automatic document feeder 107 is provided with a pickup roller 32 for delivering the documents 3, a separating roller 31 for separating the documents 3 delivered by the pickup roller 32 one sheet by one sheet, a bending detection sensor 69 installed between the pickup roller 32 and the separating roller 31, and a control part inputted with a signal of the bending detection sensor 69. The bending detection sensor 69 is provided with a contact piece 82 capable of being pushed up by the bent documents. The control part performs a control to stop the feeding of the documents 3 when the pushed up state of the contact piece 82 is continued for a prescribed time. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a configuration of an automatic document feeder provided in a document reading device. More specifically, the present invention relates to a configuration for preventing damage to a document due to a paper jam in this type of automatic document feeder.

A paper feeding cassette of a copying machine disclosed in Patent Document 1 includes a pickup roller that picks up a sheet from a paper feeding tray, a paper feeding roller that feeds a sheet picked up by the pickup roller, and a sheet one by one. And a sheet feeding device provided with a loop detection sensor between the pickup roller and the sheet feeding roller. When the loop detection sensor is turned on, the sheet feeding device is controlled by the control means so as to disengage the electromagnetic clutch and stop the rotation of the pickup roller. Patent Document 1 assumes that this configuration can prevent the possibility of jamming due to an excessive sheet loop.
JP 2001-72268 A

  The configuration of Patent Document 1 relates to a paper feeding device of an image forming apparatus. Since a new paper is normally set in the paper feeding cassette as described above, a crease, a warp, or the like occurs in the paper. There is hardly anything.

  On the other hand, a document set on a document reading device such as an image scanner often has a fold or warp depending on the storage state. Therefore, when the configuration of the paper feeding device disclosed in Patent Document 1 is applied as it is to the automatic document feeder of the image reading apparatus, if a slight warp that does not cause jamming occurs at the edge of the document, for example, The detection of the loop detection sensor stops the conveyance of the document. Therefore, there is a possibility that the conveyance of the document frequently stops and the reading efficiency is lowered, and there is room for improvement in this respect.

Means and effects for solving the problems

  The problems to be solved by the present invention are as described above. Next, means for solving the problems and the effects thereof will be described.

  According to a first aspect of the present invention, an automatic document feeder having the following configuration is provided. That is, a pickup roller for feeding the document, a separation roller for separating the documents fed by the pickup roller one by one, a deflection detection sensor installed between the pickup roller and the separation roller, A control unit to which a signal of the bending detection sensor is input. The bending detection sensor includes a contact piece that can be pushed up by a bent document. The controller controls to stop the conveyance of the document when the state where the contact piece is pushed up continues for a predetermined time.

  As a result, even when a conveyance error occurs in the separation roller, the bending of the document generated between the separation roller and the pickup roller is detected by pushing up the contact piece of the deflection detection sensor, and the document is detected before the document is severely jammed. Can be stopped. As a result, the document can be prevented from being damaged. On the other hand, when the warp generated in the document passes through the deflection detection sensor and only pushes up the contact piece for a short time, the conveyance of the document is not stopped and the document conveyance efficiency can be improved.

  According to a second aspect of the present invention, an automatic document feeder having the following configuration is provided. That is, a pickup roller for feeding the document, a separation roller for separating the documents fed by the pickup roller one by one, a deflection detection sensor installed between the pickup roller and the separation roller, A document detection sensor disposed downstream of the deflection detection sensor in the document transport direction, and a control unit to which the deflection detection sensor and signals from the document detection sensor are input. The bending detection sensor includes a contact piece that can be pushed up by a bent document. The control unit controls to stop the conveyance of the original when the contact piece is pushed up and the original detection sensor does not detect either the head or the end of the original in the conveyance direction within a predetermined time thereafter.

  As a result, even when a conveyance error occurs in the separation roller, the bending of the document generated between the separation roller and the pickup roller is detected by pushing up the contact piece of the deflection detection sensor, and the document is detected before the document is severely jammed. Can be stopped. As a result, the document can be prevented from being damaged. On the other hand, if the warp occurring at the beginning or end of the document passes only the deflection detection sensor and only pushes up the contact piece, the document detection sensor detects the beginning or end of the document and continues to convey the document. As a result, the document conveyance efficiency can be improved.

  In the automatic document feeder, when the contact piece is pushed up and the document detection sensor does not detect either the beginning or the end of the document conveyance direction within a predetermined time after that, the separation roller It is preferable to control so that the separation roller and the pickup roller are driven again to convey the document in the forward direction after the drive is stopped and the pickup roller is reversed to reversely convey the document.

  As a result, when bending of the document is detected, the document can be automatically conveyed in reverse and re-feeding without stopping the document and waiting for the user's maintenance work. Therefore, the frequency at which the conveyance is stopped can be significantly reduced, and the document conveyance efficiency can be improved satisfactorily.

  In the automatic document feeder, it is preferable that the control unit conveys the document in the forward direction after separating the pickup roller and the document after reversing the document and then recontacting the document. .

  As a result, the pickup position and orientation of the original at the time of re-feeding are expected to change from the time of the original transfer, so that the success rate of transport of the separation roller at the time of re-feeding can be increased, and Efficiency is further improved.

  The automatic document feeder preferably has the following configuration. That is, the pickup roller is supported by a swing arm that can swing around the axis of the separation roller. The pickup roller and the document are separated and re-contacted by rotating the swing arm.

  This realizes a simple configuration for increasing the separation roller conveyance success rate at the time of re-feeding.

  Preferably, the automatic document feeder includes a document tray that can be moved up and down, and the pickup roller and the document are separated and re-contacted by lowering and raising the document tray.

  Thus, by raising and lowering the document tray, it is possible to obtain a configuration suitable for efficiently reading a large amount of documents set at a time. Further, the separation and re-contact between the document and the pickup roller are performed by lowering and raising the document tray, so that a simple configuration for increasing the separation roller conveyance success rate at the time of re-feeding is realized.

  According to another aspect of the present invention, a document reading device, a facsimile device, and an image scanner device including the automatic document feeder are provided.

  Next, embodiments of the invention will be described. FIG. 1 is a front sectional view showing a copy facsimile multifunction peripheral according to an embodiment of the present invention, FIG. 2 is a perspective view showing the details of the configuration of a separation unit and a pickup roller of an auto document feeder, and FIG. It is a block diagram which shows the electrical structure for a detection.

  As shown in FIG. 1, a copy facsimile multifunction machine 101 serving as an image reading apparatus and a facsimile apparatus includes a document table 102 on which a platen glass on which a read document is placed is disposed, and presses the read document onto the platen glass. A document table cover 103 to be fixed in this way, and an operation panel (not shown) for instructing reading start of the document and the like.

  An apparatus main body (not shown) is arranged below the document table 102. The apparatus main body is an image recording unit (not shown) for recording an image on a sheet as a recording medium, and image data via a communication line. A transmission / reception unit (not shown) for transmitting the signal is incorporated.

  The document table cover 103 is provided with an auto document feeder (automatic document feeder) 107. The auto document feeder 107 includes a document tray 11 provided on the upper part of the document table cover 103 and a paper discharge tray 12 provided below the document tray.

  Inside the document table cover 103, a curved document transport path 13 that connects the document tray 11 and the paper discharge tray 12 is formed. Document reading positions P1, P2 are set in the middle of the document transport path 13. With this configuration, the originals 3 set on the original tray 11 are separated one by one and conveyed along the curved original conveying path 13, and after passing through the original reading positions P1 and P2, the paper is discharged. It is discharged to the tray 12.

  A scanner unit (document reading unit) 21 is provided inside the document table 102. The scanner unit 21 includes a light source 22 that emits light to the document reading position P1, reflection mirrors 23, 24, and 25 that reflect reflected light from the document 3, and a condensing lens 26 that converges the reflected light. And a charge coupled device (CCD) 27 for converting the converged light into an electric signal and outputting the electric signal.

  With this configuration, the document 3 transported along the document transport path 13 is scanned at the document reading position P1, and the reflected light from the document 3 is guided to the CCD 27 to form an image. As a result, the CCD 27 can output an electrical signal corresponding to the read content. This signal and a signal of the contact image sensor 67 described later are sent to the image recording unit after appropriate conversion processing and printed, or transmitted to another facsimile apparatus via a communication line by the transmission / reception unit.

  Next, a detailed configuration of the document transport path 13 will be described. As shown in FIG. 1, a separation roller 31 and a pickup roller 32 are provided at a location where the document 3 is supplied from the document tray 11 to the document transport path 13. A swing arm 33 is attached so as to be swingable about the axis of the separation roller 31, and a pickup roller 32 is supported on the tip side of the swing arm 33. A configuration for driving the separation roller 31, the pickup roller 32, and the swing arm 33 will be described later.

  A separation pad 34 is installed at a position facing the separation roller 31, and the separation pad 34 is pressed against the peripheral surface of the separation roller 31 by a spring. A separation unit 28 is constituted by the separation roller 31 and the separation pad 34, and the separation roller 31 is driven in a state where the document 3 is nipped between the separation roller 31 and the separation pad 34, whereby one document 3 is obtained. Can be separated one by one.

  A document detection sensor 68 is provided at a position immediately downstream of the separation roller 31. The document detection sensor 68 is turned on when the top of the document 3 supplied from the document tray 11 and conveyed by the separation roller 31 crosses the detection area of the document detection sensor 68, and turned off when the end of the document 3 passes. It is configured. As shown in FIG. 3, the document detection sensor 68 is electrically connected to a control unit 85 described later.

  A plurality of conveying rollers 61, 62, 63, 64 are provided downstream of the separation roller 31. Thereby, the document 3 conveyed downstream by the driving of the separation roller 31 is further nipped by the conveyance rollers 61, 62, 63 and further conveyed, and passes the document reading position P1. At this time, information on the document 3 is read by the scanner unit 21.

  The document 3 is further transported by driving the transport roller 64 and passes the document reading position P2. The document reading position P2 is provided with a contact image sensor 67, and the content on the back side of the document 3 can be scanned while the document 3 is nipped between the contact image sensor 67 and the platen roller 65. It is like that. The document 3 whose contents on both the front and back sides are read at the two document reading positions P1 and P2 is conveyed by the sheet discharge roller 70 and discharged onto the sheet discharge tray 12.

  The rollers (separation roller 31, transport rollers 61, 62, 63, 64, paper discharge roller 70, etc.) arranged in the document transport path 13 are driven by an electric motor (not shown) provided in the drive unit 87 shown in FIG. The The drive / stop of the drive unit 87 is controlled based on a signal from the control unit 85.

  Next, a configuration around the separation roller 31 and the pickup roller 32 will be described in detail with reference to a perspective view of a main part in FIG.

  As shown in FIG. 2, a drive shaft 41 is disposed concentrically with the separation roller 31, and a first clutch 51 is interposed between the drive shaft 41 and the separation roller 31. The first clutch 51 is configured as a one-way clutch. When the drive shaft 41 rotates in the direction of the arrow in FIG. 2, it transmits it to the separation roller 31, while when the drive shaft 41 rotates in the opposite direction, When the separation roller 31 rotates at a higher speed than the drive shaft 41, the separation roller 31 is automatically cut so that the drive shaft 41 rotates freely with respect to the separation roller 31.

  The swing arm 33 has a structure in which a pair of arm bodies 35, 35 arranged so as to sandwich the separation roller 31 are connected by a beam portion 36. The base portion of each arm body 35 is supported by the drive shaft 41, and the roller shaft 42 is supported by the tip portion of the swing arm 33. The pickup roller 32 is rotatably supported on the roller shaft 42. The pickup roller 32 is disposed so as to be sandwiched between the two arm bodies 35 and 35.

  A driving pulley 43 is integrally fixed to the driving shaft 41 at a position on one side of the separation roller 31. On the other hand, a driven pulley 44 is rotatably supported on the roller shaft 42 at a position on one side of the pickup roller 32. An endless transmission belt 45 is stretched between the drive pulley 43 and the driven pulley 44.

  A second clutch 52 is interposed between the driven pulley 44 and the pickup roller 32. Similarly to the first clutch 51, the second clutch 52 is also configured as a one-way clutch. When the driven pulley 44 rotates in the direction of the arrow in FIG. Is rotated in the opposite direction, and when the separation roller 32 rotates at a higher speed than the driven pulley 44, the driven pulley 44 is configured to idle with respect to the pickup roller 32. .

  A torque limiter 53 is disposed between the driven pulley 44 and the arm body 35 on one side. When the driven pulley 44 rotates in the direction of the arrow in FIG. 2, the torque limiter 53 transmits the torque to the arm body 35 to rotate the swing arm 33 downward, while the torque is reduced to a predetermined value. When the value is exceeded, the driven pulley 44 is configured to idle with respect to the arm body 35.

  With the above configuration, when the drive shaft 41 is rotated in the direction of the arrow in FIG. 2 by the electric motor (not shown) of the drive unit 87 (FIG. 3), the rotation is transmitted to the separation roller 31 by the first clutch 51. Rotates. Further, since the drive pulley 43 rotates integrally with the drive shaft 41, this rotation is transmitted to the driven pulley 44 via the transmission belt 45, and the driven pulley 44 rotates in the direction of the arrow in FIG. The rotation of the driven pulley 44 is transmitted to the pickup roller 32 by the second clutch 52, and the pickup roller 32 rotates. Further, since the rotation of the driven pulley 44 is transmitted to the arm body 35 via the torque limiter 53, the swing arm 33 starts to rotate downward from the position (standby position) indicated by the chain line in FIG.

  The pickup roller 32 descends as the swing arm 33 rotates downward, and comes into contact with the uppermost document 3 among the documents 3 set on the document tray 11 (shown by a solid line in FIG. 1). Feeding position). As a result, the document 3 is fed by the pickup roller 32 and sent to the nip portion between the separation roller 31 and the separation pad 34. Since the swing arm 33 receives a reaction force when the pickup roller 32 comes into contact with the document 3, the torque limiter 53 does not transmit the rotation of the driven pulley 44 to the arm body 35, and the swing arm 33 moves downward. Stops turning.

  The documents 3 are separated one by one at the nip portion between the separation roller 31 and the separation pad 34 and then conveyed downstream to the conveyance roller 61 (FIG. 1). Here, since the peripheral speed of the rotating transport roller 61 is set to be larger than the peripheral speed of the separation roller 31, the separation roller 31 rotates around the document 3 transported by the transport roller 61. The rotation speed of the separation roller 31 exceeds the rotation speed of the drive shaft 41. As a result, the first clutch 51 is disconnected, and the separation roller 31 rotates idly with respect to the drive shaft 41.

  Thereafter, when the document 3 sent by the transport roller 61 passes through the nip portion between the separation roller 31 and the separation pad 34, the separation roller 31 is not rotated along with the document 3, so that the first clutch 51 is connected again. As a result, the separation roller 31 is driven again by the drive shaft 41, and the conveyance of the next document 3 fed by the pickup roller 32 is started.

  Next, when it is detected by a sensor (not shown) that the document 3 has disappeared from the document tray 11, an electric motor of a drive unit (not shown) drives the drive shaft 41 in the direction opposite to the arrow in FIG. Then, the reverse rotation of the drive shaft 41 is transmitted to the driven pulley 44 via the drive pulley 43 and the transmission belt 45, and the reverse rotation of the driven pulley 44 is transmitted to the arm body 35 via the torque limiter 53. As a result, the swing arm 33 rotates upward, and the pickup roller 32 rises to the position of the chain line (standby position) in FIG. Note that when the drive shaft 41 rotates in the reverse direction, the first clutch 51 and the second clutch 52 are disconnected, so that the separation roller 31 and the pickup roller 32 do not rotate in the reverse direction.

  Next, a configuration for detecting the bending of the document 3 will be described. As shown in FIGS. 1 and 2, a deflection detection sensor 69 is disposed at a position between the pickup roller 32 and the separation roller 31. As shown in FIG. 2, the bending detection sensor 69 includes a sensor housing 81 and a contact piece 82 supported by the sensor housing 81 so as to protrude downward.

  The bending detection sensor 69 is installed between the pair of arm bodies 35 and 35 and is sandwiched between the pickup roller 32 and the separation roller 31. The contact piece 82 is supported by the sensor housing 81 so as to be movable up and down, and is biased downward by a biasing spring (not shown). When the contact piece 82 is pushed up against the biasing spring, the contact piece 82 is turned on, and a deflection detection signal is transmitted to the control unit 85 (FIG. 3).

  As shown in the block diagram of FIG. 3, the auto document feeder 107 includes a control unit 85 configured as a microcomputer. The control unit 85 receives a signal from the deflection detection sensor 69 and a signal from the document detection sensor 68. Further, a timer circuit (timer) 86 is connected to the controller 85, and the timing / drive timing of each roller driven by the driver 87 can be accurately controlled by the timekeeping function.

  Then, when the deflection detection sensor 69 is turned on while the document 3 is being conveyed by the drive unit 87, the control unit 85 of the present embodiment displays the time during which the deflection detection sensor 69 is in the ON state. 86. When the ON state is continued for a predetermined time, the control unit 85 immediately sends a conveyance stop signal to the drive unit 87 to control the conveyance of the document 3 (reading of the image) and to stop the document conveyance abnormality. For example, the fact is displayed on the display of the operation panel.

  The effect by the above control is demonstrated. That is, as shown in FIG. 4, after the document 3 on the document tray 11 is fed by the pickup roller 32, the separation roller 31 cannot slide the document 3 downstream and slides with respect to the document 3 to make it idle. There is a case. There are various causes of the conveyance error of the separation roller 31. For example, the surface of the separation roller 31 is worn, paper dust is accumulated on the surface of the separation roller 31, and the original 3 is wrinkled.

  In this case, the separation roller 31 on the downstream side slides and idles with respect to the document 3, while the pickup roller 32 continues to feed the document 3, so that the document 3 is curved so as to protrude upward, and the loop portion Form. When this bending progresses as the pickup roller 32 is driven, a severe document clogging occurs between the separation roller 31 and the pickup roller 32, causing damage such as wrinkling or tearing of the document 3.

  In this regard, in this embodiment, when the document 3 is bent (curved), the bent portion of the document 3 pushes up the contact piece 82 as shown in FIG. Then, when the ON state of the deflection detection sensor 69 continues for a predetermined time, the control unit 85 stops driving the separation roller 31 and the pickup roller 32. Accordingly, since the conveyance of the document 3 can be stopped at an early stage when the document 3 is bent, the document 3 can be prevented from being clogged or damaged.

  On the other hand, the document 3 set on the document tray 11 often has a habit such as warping or crease depending on its storage state and the like, and it is considered that the bending detection sensor 69 is turned on by this habit. For example, FIG. 5 shows a state in which the warp (curled portion) at the top of the document 3 pushes up the contact piece 82 of the bending detection sensor 69. Further, FIG. 6 shows a state in which the warp at the end of the document 3 pushes up the contact piece 82 of the bending detection sensor 69.

  In the case of a slight warp as shown in FIG. 5, the leading portion of the document 3 is normally fed into the separation unit 28 as shown by the chain line in FIG. 5 by the conveyance of the pickup roller 32 and the rotation of the separation roller 31. In most cases, the sheet is nipped and can be conveyed downstream without any problem. Further, as shown in FIG. 6, when the trailing portion of the document 3 is warped, the document 3 is already nipped by the separation roller 31 and the transport roller 61 on the downstream side, so that the document 3 is not transported at all. There is no hindrance. Therefore, if the conveyance of the document 3 is stopped in the cases as shown in FIGS. 5 and 6, the reading efficiency is lowered.

  In view of this point, in the present embodiment, when the state where the contact piece 82 is pushed up and the deflection detection sensor 69 is ON does not continue for a predetermined time or longer, the control unit 85 does not stop driving the driving unit 87, The document 3 is configured to continue to be conveyed.

  That is, when the document 3 is not conveyed by the separation roller 31 as shown in FIG. 4, the contact piece 82 of the deflection detection sensor 69 is continuously pushed up. On the other hand, as shown in FIG. 5 and FIG. 6, when the warp at the beginning or the end of the document 3 is simply pushed up the contact piece 82 of the deflection detection sensor 69, the document 3 is further conveyed and the warped portion passes. Since the pushing-up of the contact piece 82 is released, the bending detection sensor 69 returns to the OFF state again in a short time.

  Therefore, as shown in FIGS. 5 and 6, while the document 3 is bent due to the idling of the separation roller 31 as shown in FIG. 4, the conveyance of the document 3 can be stopped to prevent the document 3 from being damaged. It is possible to prevent the document reading efficiency from being excessively lowered without stopping conveyance of the document 3 against warping.

  As described above, the auto document feeder 107 provided in the copy facsimile multifunction peripheral 101 according to the present embodiment separates the pickup roller 32 for feeding the document 3 and the document 3 fed by the pickup roller 32 one by one. A separation roller 31, a deflection detection sensor 69 installed between the pickup roller 32 and the separation roller 31, and a control unit 85 to which a signal of the deflection detection sensor 69 is input. The bending detection sensor 69 includes a contact piece 82 that can be pushed up by a bent document. Then, the control unit 85 controls the conveyance of the document 3 to be stopped when the state where the contact piece 82 is pushed up continues for a predetermined time.

  As a result, when the document 3 is bent between the separation roller 31 and the pickup roller 32 due to a conveyance error of the separation roller 31, this is detected by the bending detection sensor 69, and before the document is severely jammed. 3 can be stopped. Therefore, the document 3 can be prevented from being damaged. On the other hand, when the warp generated in the document 3 only passes through the deflection detection sensor 69, the conveyance of the document 3 is not stopped, so that the reading efficiency can be prevented from being lowered.

  It should be noted that the controller 85 detects that the document detection sensor 68 disposed on the downstream side of the deflection detection sensor 69 within the predetermined time after the contact piece 82 is pushed up is both at the beginning and the end of the document 3 in the transport direction. If it is not detected, it can be controlled to stop the conveyance of the document.

  In this case as well, a severe document jam can be avoided by detecting the bending of the document 3 due to a conveyance error of the separation roller 31. On the other hand, if the document detection sensor 68 detects the beginning or end of the document 3 after the contact piece 82 is pushed up, the conveyance is continued, so that the warp generated at the beginning or end of the document 3 pushes up the contact piece 82. In this case, it is possible to prevent the reading efficiency from being lowered without stopping the conveyance.

  Further, when the contact piece 82 is pushed up and the document detection sensor 68 disposed downstream of the deflection detection sensor 69 does not detect either the head or the end of the document 3 in the conveyance direction within a predetermined time thereafter, the document 3 may be reversely conveyed as shown in FIG.

  As a configuration in this case, the second clutch 52 is omitted in the configuration shown in FIG. 2, and an electric motor for driving the pickup roller 32 is separately provided so that the pickup roller 32 can be driven to rotate forward and backward. Then, when the bent portion of the document 3 pushes up the contact piece 82 of the deflection detection sensor 69 and the document detection sensor 68 does not detect the beginning or the end of the document 3 within a predetermined time thereafter, the drive shaft 41 is driven. The pickup roller 32 is stopped to stop the separation roller 31 and the pickup roller 32 is reversely rotated so as to return the document 3 to the document tray 11 side. At this time, since the first clutch 51 is automatically disconnected, the separation roller 31 can freely follow the reversely fed document 3.

  By this reverse conveyance, the document 3 moves upstream while eliminating the bending. When the document 3 is returned to the almost original position, the control unit 85 drives the drive unit 87 and rotates the swing arm 33 upward to temporarily separate the pickup roller 32 from the document 3. Then, the control unit 85 immediately rotates the swing arm 33 downward, re-contacts the pickup roller 32 with the document 3 and rotates in the forward direction, and again feeds the document 3 toward the downstream side (in the forward direction). To control.

  If the separation roller 31 can normally convey the document 3 during this re-feeding, the document 3 can be continuously read without stopping the conveyance and waiting for the user's maintenance work. Further, when the pickup roller 32 is once separated from the original 3 and brought into contact with the original 3 again, the pickup position and orientation of the original 3 at the time of re-feeding are changed as compared with those at the first time, and the separation roller 31 is This time, it can be expected that the document 3 is conveyed normally.

  As described above, in the configuration of FIG. 7, when the contact piece 82 is pushed up and the original detection sensor 68 does not detect either the head or the end of the original 3 in the conveyance direction within the predetermined time thereafter, the control is performed. The unit 85 stops the driving of the separation roller 31, reverses the pickup roller 32 and reversely conveys the document 3, and then drives the separation roller 31 and the pickup roller 32 again to convey the document 3 in the forward direction. Control to do.

  As a result, when the deflection of the document 3 is detected by the deflection detection sensor 69, the document 3 is automatically reversely conveyed to the original position and then fed again. Thereby, the frequency at which the conveyance is stopped can be significantly reduced, and the reading efficiency is improved.

  Further, the control unit 85 reversely conveys the document 3 to the original position, and then separates the pickup roller 32 and the document 3 from each other and then re-contacts them to convey the document 3 in the forward direction. To control.

  As a result, it is expected that the pick-up position, orientation, etc. of the original 3 at the time of re-feeding will change from the time of the original transfer, so that the success rate of conveyance of the separation roller 31 can be increased.

  In this embodiment, the pickup roller 32 is supported by a swing arm 33 that can swing around the axis of the separation roller 31. Then, the pickup roller 32 and the document 3 are separated and recontacted by rotating the swing arm 33.

  Thereby, a simple configuration for increasing the conveyance success rate of the separation roller 31 at the time of re-feeding is realized.

  It should be noted that the configuration in which the document is reversely conveyed and fed again can be applied to an image scanner apparatus as shown in FIG. FIG. 8 is a side sectional view showing the overall configuration of the image scanner device. In the embodiment shown in FIG. 8, the same or similar members as those in the above-described embodiment (FIG. 1) are denoted by the same reference numerals, and the description thereof is omitted.

  An image scanner device 151 shown in FIG. 8 includes a large-capacity document tray 11 for setting a document 3 at the lower part of the main body and a discharge tray 12 for discharging the document 3 after reading at the upper part of the main body.

  Inside the main body of the image scanner device 151, a curved document transport path 13 that connects the document tray 11 side and the paper discharge tray 12 side is formed. The image scanner device 151 includes an auto document feeder 157, and the auto document feeder 157 includes a plurality of transport rollers 61, 62, 63, and 64 arranged along the document transport path 13.

  Further, two document reading positions P1 and P2 are set in the middle of the document transport path 13, and the contact image sensors 67 and 67 are arranged at the respective document reading positions P1 and P2 so as to correspond to the front and back sides of the document. The As a result, the front and back surfaces of the document 3 passing through the document reading positions P1 and P2 can be read by the contact image sensors 67 and 67.

  The document tray 11 is provided so as to be movable up and down along a guide rail (not shown). The auto document feeder 157 includes an electric motor 91, a pinion 92 driven by the electric motor 91, and a rack 93 that meshes with the pinion 92 and is attached to the document tray 11. Accordingly, the document tray 11 can be moved up and down by driving the pinion 92 forward and backward by the electric motor 91.

  The auto document feeder 157 includes the separation roller 31, the separation pad 34, the pickup roller 32, the deflection detection sensor 69, and the document detection sensor 68 as in the above-described embodiment. However, the swing arm 33 provided in the embodiment of FIG. 1 is omitted in this embodiment, and the pickup roller 32 is configured not to move up and down.

  With this configuration, when reading the document 3, a control unit (not shown) drives the electric motor 91 and raises the document tray 11 so that the uppermost layer of the document 3 set on the document tray 11 contacts the pickup roller 32. Let Then, the control unit drives the separation roller 31 and the pickup roller 32 of the separation unit 28 to start supplying the document 3, and the document 3 is read by the contact image sensors 67 and 67 while being conveyed one by one. The paper is discharged to the paper discharge tray 12.

  Note that the control unit causes the electric motor 91 to gradually raise the document tray 11 as the documents 3 on the document tray 11 are successively sent out by the pickup roller 32 and the separation unit 28 and the remaining amount of the document 3 decreases. To control. As a result, the state in which the pickup roller 32 and the document 3 can be contacted is maintained regardless of the remaining amount of the document 3, and the document 3 can be conveyed one after another until there are no more documents 3 set.

  Further, in this image scanner device 151, a predetermined time after the bending of the separation roller 31 is caused between the pickup roller 32 and the separation roller 31 to push up the contact piece 82 and the deflection detection sensor 69 is turned on. If the original detection sensor 68 detects neither the beginning nor the end of the original 3, the following control is performed.

  That is, the control unit (not shown) of the auto document feeder 157 stops the driving of the separation roller 31 and reversely rotates the pickup roller 32 so as to return the document 3 to the document tray 11 side. When the original 3 returns to the almost original position by the conveyance in the reverse direction, the control unit drives the electric motor 91 to lower the original tray 11 and temporarily separate the pickup roller 32 from the original 3. Then, the control unit 85 immediately raises the document tray 11, makes the pickup roller 32 re-contact with the document 3 and rotates in the forward direction, and controls the document 3 to be moved again downstream (in the forward direction). To do.

  If the separation roller 31 can normally convey the document 3 during this re-feeding, the document 3 can be continuously read without stopping the conveyance and waiting for the user's maintenance work. Further, when the pickup roller 32 is once separated from the original 3 and brought into contact with the original 3 again, the pickup position and orientation of the original 3 at the time of re-feeding are changed as compared with those at the first time, and the separation roller 31 is This time, it can be expected that the document 3 is conveyed normally.

  As described above, the auto document feeder 157 provided in the image scanner device 151 of the present embodiment includes the document tray 11 that can be raised and lowered. Then, the separation and re-contact between the pickup roller 32 and the original 3 performed when the original 3 is re-transferred is performed by lowering and raising the original tray 11.

  Thus, by moving the document tray 11 up and down, a large number of documents can be set at a time and read efficiently. Even if a conveyance error occurs due to the separation roller 31, the deflection of the document 3 is detected by the deflection detection sensor 69 before the document is severely jammed, and the document 3 is transported in the reverse direction and is re-transferred. 3 can be prevented and at the same time the reading efficiency can be improved. Furthermore, since the separation and re-contact of the document 3 with respect to the pickup roller 32 are performed by the lowering and raising of the document tray 11, a simple configuration for increasing the success rate of the separation roller 31 at the time of re-feeding is realized. .

  A plurality of preferred embodiments of the present invention have been described above, but the above configuration can be modified as follows, for example.

  The number and shape of the contact pieces 82 can be appropriately changed according to circumstances. Moreover, it can replace with the structure which urges | biases the contact piece 82 downward with an urging | biasing spring, and can change into the structure which the said contact piece 82 protrudes from the sensor housing 81 by dead weight.

  The document detection sensor 68 can be disposed, for example, at a position between the deflection detection sensor 69 and the separation roller 31 instead of being disposed downstream of the separation roller 31 in the document conveyance direction.

  Further, the document detection sensor 68 can be changed to a configuration provided on the upstream side rather than the downstream side in the document conveyance direction with respect to the deflection detection sensor 69. In this case, for example, it is conceivable to perform control so that the conveyance of the document 3 is not stopped even if the contact piece 82 is pushed up within a predetermined time after the document detection sensor detects the top or the end of the document 3.

  The separation unit 28 is not limited to the case where the separation roller 31 and the separation pad 34 are configured. For example, the separation unit 28 can be changed to a configuration in which the separation roller and the retard roller are arranged to face each other. Further, the positions and the number of the transport rollers 61, 62, 63, 64 on the downstream side of the separation unit 28 can be arbitrarily changed according to circumstances.

  The auto document feeder having the above configuration can be applied not only to an image reading unit for both an auto document feeder and a flat bed, but also to an image reading unit dedicated to the auto document feeder.

  The auto document feeder having the above-described configuration is not limited to a copy facsimile multifunction peripheral or an image scanner device, and can be applied to, for example, a copy machine or a facsimile device having a copy function or a facsimile function alone.

1 is a front sectional view showing an overall configuration of a copy facsimile multifunction peripheral according to an embodiment of the present invention. The main part perspective view which shows the structure of the isolation | separation part of an auto document feeder, and a pick-up roller in detail. . FIG. 3 is a block diagram showing an electrical configuration for detecting a document deflection. FIG. 3 is an enlarged cross-sectional view illustrating a state in which a deflection detection sensor detects the deflection of a document. FIG. 3 is an explanatory diagram illustrating a state in which a deflection detection sensor is turned on by warping of the top of a document. FIG. 3 is an explanatory diagram illustrating a state in which a deflection detection sensor is turned on due to warping at the end of a document. FIG. 3 is an explanatory diagram showing a state in which a bent document is returned to the document tray side by reverse conveyance of a pickup roller. FIG. 6 is a side cross-sectional view showing an overall configuration of an image scanner device according to another embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 3 Original 31 Separation roller 32 Pickup roller 68 Original detection sensor 69 Deflection detection sensor 82 Contact piece 85 Control part 101 Copy facsimile compound machine (facsimile apparatus, original reading apparatus)
107 Auto Document Feeder (Automatic Document Feeder)
151 Image scanner device (document reading device)
157 Auto Document Feeder (Automatic Document Feeder)

Claims (9)

A pickup roller for feeding the original,
A separation roller for separating documents fed by the pickup roller one by one;
A deflection detection sensor installed between the pickup roller and the separation roller;
A control unit to which a signal of the deflection detection sensor is input;
With
The bending detection sensor includes a contact piece that can be pushed up by a bent document,
The automatic document conveyance device, wherein the control unit controls the conveyance of the document to be stopped when the state where the contact piece is pushed up continues for a predetermined time. A pickup roller for feeding the original,
A separation roller for separating documents fed by the pickup roller one by one;
A deflection detection sensor installed between the pickup roller and the separation roller;
A document detection sensor disposed downstream of the deflection detection sensor in the document transport direction;
A control unit to which signals of the deflection detection sensor and the document detection sensor are input;
With
The bending detection sensor includes a contact piece that can be pushed up by a bent document,
The control unit controls to stop the conveyance of the document when the contact piece is pushed up and the document detection sensor does not detect either the beginning or the end of the document conveyance direction within a predetermined time thereafter. A feature of the automatic document feeder. The automatic document feeder according to claim 2,
The control unit stops driving the separation roller when the contact piece is pushed up and the document detection sensor does not detect either the beginning or the end of the document conveyance direction within a predetermined time thereafter, and the pickup roller , Reversely transporting the original and then driving the separation roller and the pickup roller again to control the original to be conveyed in the forward direction. The automatic document feeder according to claim 3,
An automatic document conveying apparatus, wherein the control unit conveys the document in a normal direction after separating the pickup roller and the document after reversing the document and bringing them back into contact with each other. The automatic document feeder according to claim 4,
The pickup roller is supported by a swing arm that can swing around the axis of the separation roller,
The automatic document feeder, wherein the pickup roller and the document are separated and re-contacted by rotating the swing arm. The automatic document feeder according to claim 4,
A document tray that can be raised and lowered,
The automatic document feeder, wherein the pickup roller and the document are separated and re-contacted by lowering and raising the document tray.   An original reading apparatus comprising the automatic original conveying apparatus according to any one of claims 1 to 6.   A facsimile apparatus as the document reading apparatus according to claim 7.   An image scanner device as a document reading device according to claim 7.

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