JP2010076932A - Automatic document conveying device and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic document conveying device can prevent skew of a document caused by imbalance of conveyance forces to a direction orthogonal to the document conveying direction, and to provide an image forming device. <P>SOLUTION: The automatic document conveying device includes: a turn part D curved to change the document conveying direction by approximately 180 degrees; an outside guide member 262 arranged outside the curvature of the turn part D to guide conveyance of the document inside the turn part D; an inside guide member 252 arranged inside the curvature of the turn part D; intermediate rollers 14 for conveying the document into the turn part D; and a read entrance roller 16 for taking the document out of the turn part D. A notch 253 is provided at a position of the inside guide member 252, between the intermediate rollers 14 and the read entrance roller 16, farther than the farthest intermediate roller 14 from a document placing reference member 251 in a direction orthogonal to the document conveying direction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an automatic document feeder and an image forming apparatus. More specifically, the present invention relates to an automatic document feeder having a curved path so as to change the document conveyance direction by approximately 180 °, and an image including the automatic document feeder. The present invention relates to a forming apparatus.

  In recent automatic document feeders, in order to discharge a document fed from a document table to a discharge tray located under the document table, the document is turned by approximately 180 ° by a curved path. It has become mainstream.

  Conventionally, as this type of automatic document conveying device, there has been provided a rotating roller on a U-shaped reversing path for reversing the document conveying direction so as to reduce the conveyance resistance when the document passes through the reversing part. It is known (see, for example, Patent Document 1).

  In addition, this type of automatic document feeder is provided with a document guide member on each of the inner peripheral side and the outer peripheral side of the U-shaped reverse path, and the inner peripheral side document guide member can be rotated in the circumferential direction of the reversing unit Thus, there is known a document in which the conveyance resistance when the document passes through the reverse path is reduced (see, for example, Patent Document 2).

Some automatic document feeders employ a one-sided reference method in which the reference position when placing a document is not the center of the document but is based on one of the side surfaces parallel to the document conveyance direction. In the one-side reference type automatic document conveyance device, a large number of conveyance rollers are provided on the reference side in order to cope with a small-size document.
JP 2007-182262 A JP 7-315621 A

  However, in the conventional automatic document feeder as described above, a document that is bent in the curved path is strongly brought into contact with the guide member in the curved path due to the force to return to the original, so that a large conveyance resistance is generated. In particular, in an automatic document feeder that employs the one-side reference method, when a large-size document with a thick document thickness (high bending rigidity) is used, many conveyance rollers are provided to obtain a sufficient conveyance force. The document cannot be smoothly conveyed due to the conveyance resistance generated in the curved path on the non-reference side with fewer conveyance rollers than the reference side, and the non-reference side is gradually delayed with respect to the reference side, and the document is skewed. There was a problem.

  The present invention has been made in order to solve the above-described conventional problems, and an automatic document conveying device capable of preventing skewing of a document due to an imbalance in conveying force in a direction orthogonal to the document conveying direction and An object is to provide an image forming apparatus.

  An automatic document feeder according to the present invention is arranged at a document placement table on which a document before conveyance is placed and at one end of the document placement table in a direction perpendicular to the document conveyance direction, on the document placement table. A document placement reference member for aligning one end of each document in a direction orthogonal to the document transport direction, a sheet discharge tray on which the discharged document is placed, and a document from the document table to the sheet discharge tray A curved path that constitutes a part of the conveyance path and is curved so as to change the conveyance direction of the document by approximately 180 °, and an outer side that is disposed outside the curved path so as to guide the conveyance of the document in the curved path. A guide member, an inner guide member disposed inwardly of the curved path so as to guide conveyance of the document in the curved path, and a direction orthogonal to the document conveyance direction upstream of the curved path in the document conveyance direction. Multiple rows along the bay A first conveying unit that conveys the document in the path; and a second line that is provided in a plurality of rows along a direction orthogonal to the document conveying direction at a downstream portion of the curved path in the document conveying direction, and that unloads the document from the curved path. The original in a direction perpendicular to the original conveying direction of the first conveying means between the first conveying means and the second conveying means of the inner guide member. A notch is provided at a position farther from the one farthest from the mounting reference member.

  With this configuration, even in a so-called one-side reference configuration in which a large number of conveying units are arranged on the side where the document placement reference member is provided, the inner guide member is notched to reduce friction with the document. Accordingly, it is possible to reduce the conveyance resistance on the side far from the document placement reference member in the curved path, and to prevent the skew of the document due to the unbalance of the conveyance force in the direction orthogonal to the document conveyance direction.

  The automatic document feeder according to the present invention is characterized in that a plurality of the notches are provided in a direction perpendicular to the document conveyance direction.

  With this configuration, it is possible to provide a plurality of small cutouts instead of providing one large cutout, and when one large cutout is provided, the leading edge of the document can be prevented from being caught by the cutout. The conveyance resistance can be reduced in a wide range far from the document placement reference member in the curved path.

  In the automatic document feeder according to the present invention, the width of the cutout in a direction perpendicular to the document conveyance direction is narrowed from the upstream side to the downstream side in the document conveyance direction.

  With this configuration, the leading edge of the document can be prevented from being caught by the notch.

  The automatic document feeder according to the present invention is characterized in that a soft sheet member is provided on the back surface of the notch of the inner guide member.

  With this configuration, even when a large cutout is provided, foreign matter can be prevented from entering the inside guide member from the cutout.

  Further, the automatic document feeder according to the present invention is characterized in that a roller that rotates when contacting the document passing through the curved path is provided in the notch.

  With this configuration, it is possible to reduce the conveyance resistance more efficiently on the side of the curved path farther from the document placement reference member, and to prevent skewing of the document due to unbalance of the conveyance force in the direction orthogonal to the document conveyance direction. be able to.

  Further, in the automatic document feeder according to the present invention, the outer peripheral surface of the roller is curved outward from the inner guide member, and is positioned to be curved inward by the thickness of the document from the outer guide member. It is characterized by arranging rollers.

  With this configuration, it is possible to reliably suppress the occurrence of conveyance resistance due to contact between the original and the inner guide member due to rotation of the roller in contact with the original, and between the outer guide member and the roller. Since a document conveyance space is secured, it is possible to prevent the document from being jammed in the curved path.

  In the automatic document feeder according to the present invention, the roller is made of a material having a small friction coefficient.

  With this configuration, since slippage occurs between the original and the roller, it is possible to reduce the conveyance resistance of the original in the portion in contact with the roller, and to prevent the original from being unbalanced due to the unbalance of the conveyance force in the direction perpendicular to the original conveyance direction. Skew can be prevented.

  The automatic document feeder according to the present invention is characterized in that the roller has a rotating shaft formed integrally with the roller.

  With this configuration, since the roller and the rotating shaft are integrally molded, an increase in the number of parts can be prevented and manufacturing costs can be suppressed.

  In addition, an image forming apparatus according to the present invention includes the above-described automatic document feeder.

  With this configuration, even in the image forming apparatus including the automatic document feeder, it is possible to provide an image in which the inclination of the image due to the oblique conveyance is suppressed to be small.

  According to the present invention, it is possible to provide an automatic document feeder and an image forming apparatus that can prevent skewing of a document due to an unbalance of a conveyance force in a direction orthogonal to the document conveyance direction.

  Embodiments of the present invention will be described below with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic configuration diagram of an automatic document feeder and an image forming apparatus including the automatic document feeder according to the first embodiment of the present invention. FIG. 2 is a configuration diagram of the automatic document feeder according to the first embodiment of the present invention. FIG. 3 is a block diagram of a control system of the automatic document feeder according to the first embodiment of the present invention. Note that the image forming apparatus has functions of a copying machine, a facsimile machine, a multifunction machine having a copying function and a facsimile function, and the like.

  First, the configuration will be described.

  As shown in FIGS. 1 and 2, the image forming apparatus 70 includes an automatic document conveying device 50 that conveys a document, and an image forming apparatus main body 60 that reads a document and forms an image on a transfer sheet. . The automatic document feeder 50 is provided so as to be openable and closable with respect to the image forming apparatus main body 60 via a hinge mechanism (not shown).

  An image reading unit 81 is provided in the image forming apparatus main body 60, and image information read by the image reading unit 81 is applied to the photosensitive drum 83 by the writing unit 82.

  The image reading unit 81 includes a light source 81a that illuminates a document on the contact glass 22 or the slit glass 21, a first mirror 81b, a second mirror 81c, a third mirror 81d that reflect light reflected from the document, and a first mirror 81d. A lens 81e that forms an image of the light reflected from the three mirrors 81d on the CCD image sensor 81f and a CCD image sensor 81f that converts the light imaged by the lens 81e into an electrical signal are provided.

  The light source 81a and the first mirror 81b are attached to a first traveling body (not shown), and the second mirror 81c and the third mirror 81d are attached to the second traveling body, and the first traveling body and the second traveling body. Moves along the contact glass 22 and the slit glass 21.

  When the first traveling body and the second traveling body read a document placed on the contact glass 22, the first traveling body and the second traveling body are moved in the left-right direction in FIG. When reading, it is stopped below the slit glass 21.

  The writing unit 82 irradiates a laser beam light-modulated according to the image information read by the image reading unit 81, and exposes the surface of the charged photosensitive drum 83 with the laser beam.

  Around the photosensitive drum 83, a developing device 86, a transfer belt 87, a cleaning device 88, a charging device and a charge eliminating device (not shown) that form an image forming unit together with the photosensitive drum 83 are provided. The charging device controls the corona discharge with a positive charge in the dark by a grid to charge the surface of the photosensitive drum to a constant potential.

  The writing unit 82 irradiates a laser diode containing image information onto the photosensitive drum 83 charged at this constant potential to remove negative charges on the photosensitive drum 83 to form an electrostatic latent image.

  The developing device 86 forms a visible image by attaching a negatively charged toner to the electrically removed portion on the photosensitive drum 83. A positive bias is applied to the transfer belt 87, and the transfer belt 87 transfers a negatively charged visible image onto a transfer sheet (paper) as a recording medium for conveyance.

  The cleaning device 88 is provided with a cleaning blade, and scrapes off the toner remaining on the photosensitive drum 83. The static eliminator turns on the internal LED to remove the residual charge on the photosensitive drum 83 and prepares to form a new image on the next transfer sheet.

  The transfer paper on which an image has been formed by the above process is conveyed to the fixing device 90 and the toner image is fixed by the fixing device 90.

  The image forming apparatus main body 60 is provided with storage cassettes 91 to 95 in which transfer papers of different sizes are stored, and the transfer paper stored in the storage cassettes 91 to 95 is called by calling rollers 91a to 95a. After being fed by the paper feed rollers 91b to 95b and the paper feed rollers 91b to 95b rotating in the transport direction and separated by the reverse rollers 91c to 95c rotating in the separation direction, the relay roller pair 96, The sheet is conveyed to a registration roller pair 98 through 97, and is timed by the registration roller pair 98 to be conveyed to a conveyance path between the photosensitive drum 83 and the transfer belt 87.

  On the other hand, as shown in FIG. 2, the automatic document feeder 50 includes a document table 2 on which a document bundle 1 composed of a plurality of documents is placed with the document surface facing upward, and a document bundle placed on the document table 2. 1. Pickup roller 7 for conveying the topmost document from 1; paper feed belt 9 and reverse roller 10 for separating the document conveyed by the pickup roller 7; A pull-out roller 12, an intermediate roller 14, and a reading entrance roller 16 that conveys to the vicinity of the slit glass 21, a reading roller 19 that conveys the original conveyed to the vicinity of the slit glass 21 while making contact with the slit glass 21, and the slit glass A reading exit roller 23 that further conveys a document that has been read at a reading position 20 of 21, and a reading exit roller 23 Ri and discharge rollers 28 for discharging the conveyed original, and a discharge tray 29 ejected documents is placed.

  The intermediate rollers 14 convey the documents conveyed by the pull-out roller 12 into the turn portion D, and are arranged in a plurality of rows along the direction orthogonal to the document conveyance direction at the upstream portion of the turn portion D in the document conveyance direction. Yes. The intermediate roller 14 constitutes a first conveying unit in the present invention.

  The reading entrance rollers 16 convey the originals transported from the turn part D to the vicinity of the slit glass 21, and are arranged in a plurality of rows along the direction orthogonal to the original conveyance direction at the downstream part of the turn part D in the original conveyance direction. Has been. The reading entrance roller 16 constitutes a second conveying unit in the present invention.

  The document placed on the document table 2 passes through each part of the transport path before being discharged to the discharge tray 29. The conveyance path includes a document setting unit A on which the document bundle 1 is placed, a separation feeding unit B that separates and feeds one document from the placed document bundle 1, and a feeding document. A registration unit C that draws and conveys a document after alignment, a turn unit D that turns the conveyed document and conveys the document surface downward, and a surface of the document. A first reading conveyance unit E that reads from below the slit glass 21, a second reading conveyance unit F that reads the back side of the document, a paper discharge unit G that discharges the document whose front and back sides have been read out, and a discharge unit G And a stack portion H on which a document is placed. Here, the front surface of the document refers to the surface that faces upward on the document table 2 and is read by the first reading / conveying section E, and the back surface of the document faces downward on the document table 2 and corresponds to the second reading / conveying section F. This is the surface where reading is performed.

  The turn part D constitutes a part of a document transport path from the document table 2 to the paper discharge tray 29, and is a curved path curved so as to change (reverse) the document transport direction by approximately 180 °. Outer guide members 261 and 262 for guiding the conveyance of the document in the turn part D are arranged outside the turn part D, and the document in the turn part D is conveyed in the curve part of the turn part D. An inner guide member 252 for guiding is arranged.

  As shown in FIG. 3, the automatic document feeder 50 includes a controller 100 that controls the entire automatic document feeder 50. The automatic document feeder 50 also includes a registration sensor 17, a document set sensor 5, a paper discharge sensor 24, an abutment sensor 11, a document width sensor 13, a reading entrance sensor 15, a sensor for inputting a signal to the controller 100. A paper proper position sensor 8 and a home position sensor 6 are provided. The automatic document feeder 50 also includes a second reading unit 25, a pickup motor 101, a paper feed motor 102, a reading motor 103, a paper discharge motor 104, a bottom plate lift, and the like as an actuator that controls driving by outputting a signal from the controller 100. A motor 105 is provided.

  The image forming apparatus main body 60 includes a main body control unit 111 that controls the image forming apparatus main body 60 and an operation unit 108 that performs various input operations and operation instructions. The controller 100 and the main body control unit 111 are connected via the I / F 107, and data such as a control signal is exchanged between them.

  FIG. 4 is a block diagram showing the configuration of the image reading unit of the automatic document feeder according to the first embodiment of the present invention.

  As shown in FIG. 4, the second reading unit 25 includes a light source unit 200 that irradiates light on a document based on a lighting signal from the controller 100, a plurality of sensor chips 201 that receive reflected light from the document, A plurality of amplifying units 202 that amplify signals output from the sensor chip 201, an A / D 203 that converts the amplified signals from analog signals to digital signals, and an image processing unit 204 that performs image processing on the digitally converted signals. A frame memory 205 that stores the image-processed signal, an output control circuit 206 that controls output of the signal stored in the frame memory 205 based on a timing signal from the controller 100, and a signal from the output control circuit 206 Is provided to the main body control unit 111. The second reading unit 25 is supplied with power from the controller 100.

  Here, the detailed configuration of the automatic document feeder 50 will be described according to the order in which the documents placed on the document table 2 are discharged to the discharge tray 29.

  First, a document bundle 1 composed of a plurality of documents is placed on a document table 2 including a movable document table 3 with the surface facing upward. Next, the position in the width direction of the document bundle 1, that is, the position in the direction orthogonal to the conveyance direction is positioned by a side guide (not shown). The placement of the document on the document table 2 is detected by the set filler 4 and the document set sensor 5, and a detection signal is output to the main body control unit 111 of the image forming apparatus main body 60 via the I / F 107.

  An outline of the length of the document in the conveyance direction is detected by document length detection sensors 30 and 31 provided on the surface of the document table 2. As the document length detection sensors 30 and 31, a reflection type sensor that detects without contact with the document by optical means or a contact type actuator that can detect even when there is only one document can be used. . The document length detection sensors 30 and 31 are arranged so that it can be determined whether the document is placed vertically or horizontally.

  The movable document table 3 is configured to move up and down in the directions of arrows a and b in FIG. When it is detected by the set filler 4 and the document set sensor 5 that the document is placed on the document table 2, the controller 100 rotates the bottom plate raising motor 105 in the normal direction so that the uppermost document in the document bundle 1. The movable document table 3 is raised so as to come into contact with the pickup roller 7. Hereinafter, the position where the uppermost document of the document bundle 1 contacts the pickup roller 7 is referred to as an appropriate feeding position.

  The pickup roller 7 is operated by the pickup motor 101 in the directions of arrows c and d in FIG. 2 via the cam mechanism, and is pushed by the document on the raised movable document table 3 and lifted in the direction of arrow c. An upper limit of movement is detected by the position sensor 8. The proper paper feed position sensor 8 is a sensor for detecting that the movable original table 3 is raised and the uppermost original of the original bundle 1 is maintained at an appropriate height.

  When the operation unit 108 is operated to specify either the double-side mode or the single-side mode, the print key is pressed, and a document feed signal is output from the main body control unit 111 to the controller 100 via the I / F 107. The controller 100 rotates the pickup roller 7 by rotating the paper feed motor 102 forward. The pick-up roller 7 that has started rotating picks up the uppermost document on the document table 2 or several documents including the uppermost document.

  Next, when the paper feeding motor 9 is rotated forward by driving the paper feeding belt 9 and the reverse roller 10 clockwise, the paper feeding belt 9 guides the original in the paper feeding direction, and the reverse roller 10 sets the original in the paper feeding direction. Since the document is pushed out in the opposite direction, the uppermost document in the document bundle 1 and the document below it are separated, and only the uppermost document is fed.

  Specifically, the reverse roller 10 is in contact with the paper feed belt 9 at a predetermined pressure, and in the state of being in direct contact with the paper feed belt 9 or in the state of being in contact with one original, the paper feed belt 9. 9 is rotated in a counterclockwise direction different from the original driving direction by the action of a torque limiter (not shown). Further, when two or more documents enter between the paper feed belt 9 and the reverse roller 10, the reverse roller 10 does not rotate with the paper feed belt 9, but rotates in the clockwise direction, which is the original driving direction. It works to push back excess originals and prevent double feeding.

  The original separated by the action of the paper feeding belt 9 and the reverse roller 10 is sent by the paper feeding belt 9, and then the leading edge of the original is detected by the abutting sensor 11, and further conveyed and stopped. The pull-out roller 12 is in contact with the pull-out roller 12. Next, when the original fed by a predetermined distance from the position detected by the abutting sensor 11 is pressed against the pull-out roller 12 with a predetermined amount of deflection, the paper feed motor 102 is stopped and the paper feed belt 9 is stopped. The drive stops. At this time, the pickup motor 101 is rotated to retract the pickup roller 7 from the upper surface of the document, and the document is fed only by the conveying force of the paper feed belt 9, whereby the leading edge of the document is sandwiched between the pull-out rollers 12 and Matching, so-called skew correction is performed. The pull-out roller 12 has a skew correction function and is used to convey the skew-corrected document after separation to the intermediate roller 14 and is driven by the reverse rotation of the paper feed motor 102. When the paper feed motor 102 rotates in the reverse direction, the pull-out roller 12 and the intermediate roller 14 are driven, but the pickup roller 7 and the paper feed belt 9 are not driven.

  The document width sensor 13 is composed of a plurality of photoelectric conversion elements such as a contact image sensor called CIS arranged in a direction perpendicular to the document transport direction, and is not shown in the figure disposed at the opposite portion of the transport path. The light reception level of the direct light emitted from the irradiation light source is output. When the document passes the position of the document width sensor 13, the controller 100 detects a level difference between a portion shielded by the document and a portion not shielded by the document width sensor 13, and is conveyed by the pull-out roller 12. The size of the document in the width direction is determined and notified to the main body control unit 111. The length of the document in the conveyance direction is detected from the motor pulse by reading the leading edge and the trailing edge of the document with the butting sensor 11. When the document is transported from the resist section C to the turn section D by driving the pull-out roller 12 and the intermediate roller 14, the transport speed at the resist section C is set higher than the transport speed at the first reading transport section E. Thus, the processing time for sending the document to the first reading conveyance unit E is shortened.

  Control after the leading edge of the document is detected by the reading entrance sensor 15 differs depending on whether the operation mode is the non-stop mode or the stop mode.

  In the non-stop mode, before the leading edge of the document enters the nip portion of the reading entrance roller 16, the reading motor 103 is driven to rotate forward at the same time as deceleration is started in order to make the document conveying speed equal to the reading conveying speed. The reading inlet roller 16, the reading outlet roller 23, and the CIS outlet roller 27 are driven.

  Thereafter, the leading edge of the document is detected by the registration sensor 17 and the first surface (document surface) with respect to the main body control unit 111 at the timing when the leading edge of the document detected by the pulse count of the reading motor 103 reaches the reading position 20. A gate signal indicating an effective image area in the sub-scanning direction is transmitted until the trailing edge of the original passes through the reading position 20.

  On the other hand, in the stop mode, after the leading edge of the document is detected by the reading inlet sensor 15, a predetermined pulse count number is supplied so that a predetermined amount of deflection occurs after the document hits the nip portion of the reading inlet roller 16. After the paper motor 102 is driven, the document is stopped (resist stop), and a registration stop signal is transmitted to the main body control unit 111 via the I / F 107. That is, the position where the reading entrance roller 16 is provided is a stop position where the document stops.

  Subsequently, when a reading start signal is received from the main body control unit 111, the document whose registration has been stopped is transported at an increased speed to reach a predetermined transport speed until the leading edge reaches the reading position 20.

  Thereafter, the leading edge of the document is detected by the registration sensor 17, and at the timing when the leading edge of the document detected by the pulse count of the reading motor 103 reaches the reading position 20, the sub-scanning direction of the first surface with respect to the main body control unit 111. A gate signal indicating an effective image area is transmitted until the trailing edge of the document passes through the reading position 20.

  When the operation mode is the single-sided mode, the controller 100 conveys the document that has passed through the first reading conveyance unit E to the paper discharge unit G via the second reading unit 25. At this time, when the leading edge of the document is detected by the paper discharge sensor 24, the controller 100 drives the paper discharge motor 104 to rotate forward to rotate the paper discharge roller 28 counterclockwise. The controller 100 counts the pulses of the paper discharge motor 104 after the paper discharge sensor 24 detects the leading edge of the original, and the paper discharge motor 104 immediately before the trailing edge of the original comes out of the nip area of the paper discharge roller 28. The driving speed is reduced so that the document discharged onto the paper discharge tray 29 does not jump out.

  As described above, in the stop mode, the document is temporarily stopped by the reading entrance roller 16 when the leading edge is detected by the reading entrance sensor 15, and in the non-stop mode, the document is conveyed without being temporarily stopped.

  When the operation mode is the duplex mode, the controller 100 counts the pulses of the reading motor 103 after the leading edge of the document is detected by the paper discharge sensor 24, and the leading edge of the document reaches the second reading unit 25. At timing, a gate signal indicating an effective image area in the sub-scanning direction is output to the second reading unit 25. The gate signal is continuously output from the second reading unit 25 until the trailing edge of the document comes out.

  The surface of the second reading unit 25 is subjected to an antifouling coating process in order to prevent transfer of foreign matters on the glue attached to the document. The second reading roller 26 is disposed so as to face the second reading unit 25, and when the original passing through the second reading unit 25 is pressed against the second reading unit 25, the floating of the original in the second reading unit 25 is suppressed. At the same time, it also serves as a reference white part for acquiring shading data in the second reading unit 25 and performing shading correction. That is, the second reading roller 26 also serves as a white shading member.

  FIG. 5 is a perspective view showing the automatic document feeder according to the first embodiment of the present invention. FIG. 6 is an enlarged view showing a turn portion of the automatic document feeder according to the first embodiment of the present invention.

  As shown in FIGS. 5 and 6, the automatic document feeder 50 is disposed at one end of the document table 2 on the document table 2 in the direction perpendicular to the document transport direction, and in the document transport direction of each document on the document table 2. A document placement reference member 251 that aligns one end in the orthogonal direction is provided.

  Between the intermediate roller 14 and the reading entrance roller 16 (see FIG. 2) of the inner guide member 252, from the document placement reference member 251 in the direction orthogonal to the document conveyance direction among the plurality of rows of intermediate rollers 14. A notch 253 is provided at a position far from the farthest. The notch 253 functions as a non-contact portion for reducing the conveyance resistance of the original, and reduces the conveyance resistance on the right front side of the turn portion D in FIGS. 5 and 6. . 5 and 6 show a state in which the conveying rollers and the like on the curved outer side of the turn portion D including the outer guide member 262 are removed from the automatic document conveying device 50. FIG.

  For this reason, even in a so-called one-side reference configuration in which a large number of conveying means are arranged on the side where the document placement reference member 251 is provided, a notch 253 is provided in the inner guide member 252 to reduce friction with the document. By reducing this, the conveyance resistance on the side far from the document placement reference member 251 in the turn portion D (the right front side in FIGS. 5 and 6) is reduced, and the document is caused by the unbalance of the conveyance force in the direction orthogonal to the document conveyance direction. Can be prevented.

  FIGS. 7A to 7C are views showing notches of the turn portion of the automatic document feeder according to the first embodiment of the present invention.

  As shown in FIG. 7A, a plurality of cutouts 253 may be provided in a direction orthogonal to the document conveyance direction. In this case, a plurality of small cutouts 253 are provided instead of one large cutout 253. When one large cutout 253 is provided, it is possible to prevent the leading edge of the original from being caught by the cutout 253 and to transport the turn portion D in a wide range far from the original placement reference member 251. Resistance can be reduced.

  Further, as shown in FIG. 7B, the notch 253 is formed in a trapezoidal shape, and the width of the notch 253 in the direction perpendicular to the document conveyance direction is narrower from the upstream side to the downstream side in the document conveyance direction. In this case, the leading edge of the document can be prevented from being caught by the notch 253. Note that the shape of the notch 253 is not limited to a trapezoid but may be an ellipse or an inverted triangle as long as the leading edge of the document can be prevented from being caught by the notch 253.

  Further, as shown in FIG. 7C, a soft sheet member 254 may be provided on the back surface of the notch 253 of the inner guide member 252. When the sheet member 254 is provided, the shape of the notch 253 is not limited to the rectangular shape shown in FIG. 7A, and may be the one shown in FIG. 7A or the one shown in FIG. As described above, by providing the sheet member 254 on the back surface of the notch 253, even when the notch 253 is made large in order to reduce the conveyance resistance, the notch 253 is inserted into the inner guide member 252. Foreign matter can be prevented from entering. Note that the sheet member 254 must be provided within a range that does not prevent other notches such as sensor holes (not shown) provided in the inner guide member 252. The form of the notch 253 may be other than that illustrated in FIGS. 7A to 7C as long as it has a function as a non-contact portion for reducing the document conveyance resistance.

  Next, the operation will be described.

  The document conveyed into the turn part D by the intermediate roller 14 is guided by the outer guide member 262 and the inner guide member 252 and is curved. At this time, the curved document passes through the turn portion D while partially contacting the outer guide member 262 and the inner guide member 252.

  The conveyance force of the document passing through the turn portion D is large because each conveyance roller is arranged in a biased manner on the side where the document placement reference member 251 is provided. On the other hand, the resistance received by the document passing through the turn portion D coming into contact with the outer guide member 262 and the inner guide member 252 reduces the contact area due to the notch 253 provided on the side far from the document placement reference member 251. Therefore, the distance is small on the side far from the document placement reference member 251.

  For this reason, on the side far from the document placement reference member 251, the insufficient conveyance force cancels out the small conveyance resistance, and the unbalance of the conveyance force in the direction orthogonal to the document conveyance direction is eliminated, and the document is skewed. Is prevented.

  As described above, the automatic document feeder 50 according to the present embodiment is arranged at the document table 2 on which the document before conveyance is placed and at one end of the document table 2 in the direction orthogonal to the document conveyance direction. The original placement reference member 251 for aligning one end of each original on the original table 2 in the direction orthogonal to the original conveyance direction, the discharge tray 29 on which the discharged original is placed, and the original table 2 A turn part D that forms a part of the document transport path to the discharge tray 29 and is curved to change the document transport direction by approximately 180 °, and a turn part D that guides the transport of the document in the turn part D. An outer guide member 262 disposed on the curved outer side, an inner guide member 252 disposed on the curved inner side of the turn portion D so as to guide the conveyance of the document in the turn portion D, and the upstream of the turn portion D in the document conveyance direction. How to transport originals Are arranged in a plurality of rows along a direction orthogonal to the intermediate roller 14 for conveying the document into the turn portion D, and arranged in a plurality of rows along the direction perpendicular to the document conveyance direction at the downstream portion of the turn portion D in the document conveyance direction. A reading entrance roller 16 that carries the document out of the turn portion D, and is located between the intermediate roller 14 and the reading entrance roller 16 of the inner guide member 252, and is a direction orthogonal to the document conveyance direction of the intermediate roller 14. Is provided with a notch 253 at a position farthest from the one farthest from the document placement reference member 251.

  With this configuration, even in a so-called one-side reference configuration in which a large number of conveying units are arranged on the side where the document placement reference member 251 is provided, a notch 253 is provided in the inner guide member 252 to cause friction with the document. Is reduced, the conveyance resistance on the side far from the document placement reference member 251 in the turn portion D can be reduced, and skewing of the document due to unbalance of the conveyance force in the direction orthogonal to the document conveyance direction can be prevented. .

  The automatic document feeder 50 according to the present embodiment is characterized in that a plurality of notches 253 are provided in a direction orthogonal to the document conveyance direction.

  With this configuration, it is possible to provide a plurality of small cutouts 253 instead of providing one large cutout 253. When one large cutout 253 is provided, the leading edge of the document is prevented from being caught by the cutout 253. In addition, the conveyance resistance can be reduced in a wide range on the side far from the document placement reference member 251 in the turn portion D.

  Further, the automatic document feeder 50 according to the present embodiment is characterized in that the width of the notch 253 in the direction orthogonal to the document conveyance direction is narrowed from the upstream side to the downstream side in the document conveyance direction. .

  With this configuration, the leading edge of the document can be prevented from being caught by the notch.

  Further, the automatic document feeder 50 according to the present embodiment is characterized in that a soft sheet member 254 is provided on the back surface of the notch 253 of the inner guide member 252.

  With this configuration, even when a large cutout 253 is provided, foreign matter can be prevented from entering the inside guide member 252 from the cutout 253.

  Similarly, the image forming apparatus 70 provided with the automatic document feeder 50 also has an inner guide member in a so-called one-side reference configuration in which a large number of conveying means are arranged on the side where the document placement reference member 251 is provided. By providing a notch 253 in 252 to reduce the friction with the original, the conveyance resistance on the side far from the original placement reference member 251 in the turn portion D is reduced, and the conveyance force in the direction perpendicular to the original conveyance direction is reduced. It is possible to prevent the skew of the original due to the balance.

  In this embodiment, the left back side in FIG. 5 is the document placement reference side with the document conveyance reference member 251, but the right front side in FIG. 5 is the document placement reference side with the document conveyance reference member 251. If the cutout 253 and the roller 255 are disposed on the left back side, which is the opposite position to the present embodiment, the same effect can be obtained.

(Second Embodiment)
FIG. 8 is an enlarged view showing a turn portion of the automatic document feeder according to the second embodiment of the present invention. FIG. 9 is a view showing a state where the rollers of the turn portion of the automatic document feeder according to the second embodiment of the present invention are attached. FIG. 10 is a view showing a roller of the turn portion of the automatic document feeder according to the second embodiment of the present invention. FIGS. 11A and 11B are cross-sectional views of the turn portion of the automatic document feeder according to the second embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the same component as 1st Embodiment, and description is abbreviate | omitted.

  As shown in FIGS. 8 to 11, a roller 255 may be provided in the notch 253 to rotate and reduce the conveyance resistance of the document when it comes into contact with the document passing through the turn portion D.

  In this case, the conveyance resistance can be reduced more efficiently on the side of the turn portion D farther from the document placement reference member 251, and skewing of the document due to unbalance in the conveyance force in the direction orthogonal to the document conveyance direction is prevented. can do.

  The roller 255 has a rotating shaft 255a formed integrally with the roller 255, whereby an increase in the number of parts can be prevented and manufacturing cost can be suppressed. The rotating shaft 255 a of the roller 255 is rotatably regulated by a retaining ring 265 so as not to be displaced in the axial direction and fall off from the inner guide member 252.

  The roller 255 is formed by using a material having a small friction coefficient such as polyacetal and having excellent slidability. For this reason, slippage occurs between the original and the roller 255, so that the roller 255 is in contact with the roller 255. It is possible to reduce the conveyance resistance of a portion of the original, and to prevent the original from being skewed due to an imbalance in the conveyance force in the direction orthogonal to the original conveyance direction.

  Further, the roller 255 is arranged such that the outer peripheral surface of the roller 255 protrudes from the inner guide member 252 by the protrusion amount d. In this state, the outer peripheral surface of the roller 255 is curved outward from the rib surface 252a of the inner guide member 252, and is positioned inward of the document by a thickness greater than the rib surface 262a of the outer guide member 262 by the thickness of the document. .

  For this reason, it is possible to reliably prevent the roller 255 from contacting the document and rotating to contact the document and the inner guide member 252 to generate a conveyance resistance, and the outer guide member 262 and the roller 255. Since a document transport space is ensured during this period, the document can be prevented from being jammed in the curved path.

  As described above, the automatic document feeder 50 according to the present embodiment is characterized in that the roller 255 that rotates when contacting the document passing through the turn portion D is provided in the notch 253.

  With this configuration, the conveyance resistance can be reduced more efficiently on the side of the turn portion D farther from the document placement reference member 251, and the skew of the document due to the unbalance of the conveyance force in the direction orthogonal to the document conveyance direction can be reduced. Can be prevented.

  Further, in the automatic document feeder 50 according to the present embodiment, the outer peripheral surface of the roller 255 is curved outward from the inner guide member 252 and is positioned inward from the outer guide member 262 by the thickness of the document or more. The roller 255 is arranged so as to do so.

  With this configuration, it is possible to reliably suppress the occurrence of conveyance resistance due to contact between the document and the inner guide member 252 due to the roller 255 contacting and rotating with the document, and the outer guide member 262 and the roller 255. Since a document transport space is secured between the document and the document, it is possible to prevent the document from being jammed in the curved path.

  The automatic document feeder 50 according to the present embodiment is characterized in that the rollers 255 are made of a material having a small friction coefficient.

  With this configuration, since slippage occurs between the original and the roller 255, it is possible to reduce the original conveyance resistance of the portion in contact with the roller 255, and due to the unbalance of the conveyance force in the direction perpendicular to the original conveyance direction. Document skew can be prevented.

  Further, the automatic document feeder 50 according to the present embodiment is characterized in that the roller 255 has a rotating shaft 255 a formed integrally with the roller 255.

  With this configuration, the roller 255 and the rotating shaft 255a are integrally formed, so that an increase in the number of parts can be prevented and manufacturing costs can be suppressed.

  In the first embodiment and the second embodiment, the notch 253 or the roller 255 is provided in the inner guide member 252, but the same effect can be obtained even if these are provided in the outer guide member 262. it can.

  As described above, the automatic document feeder and the image reading and forming apparatus according to the present invention have the effect of preventing the skew of the document due to the unbalance of the conveyance force in the direction orthogonal to the document conveyance direction. The present invention is useful as an automatic document feeder having a curved path so that the document conveyance direction is changed by approximately 180 ° and an image forming apparatus provided with the automatic document feeder.

1 is a schematic configuration diagram of an automatic document feeder according to a first embodiment of the present invention and an image forming apparatus including the automatic document feeder. 1 is a configuration diagram of an automatic document feeder according to a first embodiment of the present invention. FIG. 2 is a block diagram of a control system of the automatic document feeder according to the first embodiment of the present invention. FIG. 1 is a block diagram illustrating a configuration of an image reading unit of an automatic document feeder according to a first embodiment of the present invention. 1 is a perspective view showing an automatic document feeder according to a first embodiment of the present invention. FIG. 2 is an enlarged view showing a turn portion of the automatic document feeder according to the first embodiment of the present invention. (A)-(c) is a figure which shows the aspect of a notch of the turn part of the automatic document feeder based on the 1st Embodiment of this invention. It is an enlarged view showing a turn portion of an automatic document feeder according to a second embodiment of the present invention. It is a figure which shows the attachment state of the roller of the turn part of the automatic document feeder which concerns on the 2nd Embodiment of this invention. It is a figure which shows the roller of the turn part of the automatic document feeder based on the 2nd Embodiment of this invention. (A), (b) is sectional drawing of the turn part of the automatic document feeder based on the 2nd Embodiment of this invention.

Explanation of symbols

2 Document table (document table)
14 Intermediate roller (first conveying means)
16 Reading entrance roller (second conveying means)
29 discharge tray 50 automatic document feeder 70 image forming apparatus 251 document placement reference member 252 inner guide member 253 notch 254 sheet member 255 roller 255a rotating shaft 262 outer guide member D turn part (curved path)

Claims (9)

A document placement table on which a document before conveyance is placed;
A document placement reference member disposed at one end of the document placement table in a direction perpendicular to the document conveyance direction and aligning one end portion of each document on the document placement table in a direction perpendicular to the document conveyance direction;
A discharge tray on which the discharged document is placed;
A curved path that forms part of a document transport path from the document table to the paper discharge tray and is curved to change the document transport direction by approximately 180 °;
An outer guide member disposed outside the curved path so as to guide the conveyance of the document in the curved path;
An inner guide member disposed inside the curved path so as to guide the conveyance of the document in the curved path;
A plurality of rows arranged along a direction orthogonal to the document conveyance direction at an upstream portion in the document conveyance direction of the curved path, and a first conveyance unit that conveys the document into the curved path;
A plurality of rows arranged along a direction orthogonal to the document conveyance direction at a downstream portion of the curved path in the document conveyance direction, and a second conveyance means for conveying the document from the curved path,
The inner guide member is located farthest from the document placement reference member in the direction perpendicular to the document transport direction of the first transport unit between the first transport unit and the second transport unit. An automatic document feeder characterized in that a notch is provided at a position far from the object.   2. The automatic document feeder according to claim 1, wherein a plurality of the notches are provided in a direction perpendicular to the document conveyance direction.   2. The automatic document feeder according to claim 1, wherein a width of the cutout in a direction perpendicular to the document conveyance direction is narrowed from the upstream side to the downstream side in the document conveyance direction.   4. The automatic document feeder according to claim 1, wherein a soft sheet member is provided on a back surface of the notch of the inner guide member.   3. The automatic document feeder according to claim 1, wherein a roller that rotates when contacting the document passing through the curved path is provided in the notch.   6. The roller is disposed so that an outer peripheral surface of the roller is positioned outwardly of the curve than the inner guide member and positioned inward of the document by a thickness greater than the outer guide member by the thickness of the document. The automatic document feeder described in 1.   7. The automatic document feeder according to claim 5, wherein the roller is made of a material having a small friction coefficient.   The automatic document feeder according to any one of claims 5 to 7, wherein the roller has a rotating shaft formed integrally with the roller.   An image forming apparatus comprising the automatic document feeder according to claim 1.

Images