JP2013119464A - Automatic document feeder, image reading apparatus, and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic document feeder, an image reading apparatus, and an image forming apparatus for improving the durability of a delivery roller pair while varying the nip angle of the delivery roller pair.SOLUTION: The automatic document feeder includes the delivery roller pair 50 for delivering a document out of the feeder, a spring 57 for pressing a driven roller 50b on one side of the delivery roller pair 50 to a driving roller 50a on the other side, a rocking bracket 53 that supports the driven roller 50b and the spring 57 and rocks on a circular arc centered on the driving roller 50a independently of the driving roller 50a, and a driving gear 56 for rocking the rocking bracket 53.

Description

  The present invention relates to an automatic document feeder, an image reading device, and an image forming apparatus. More specifically, the present invention relates to an automatic document feeder that separates one document from a bundle of documents and conveys the document to a reading position. The present invention relates to an image reading apparatus and an image forming apparatus such as a scanner and a multifunction peripheral provided.

  Conventionally, in this type of automatic document feeder, when a document that has been transported and read is discharged to a paper discharge tray, the discharge stacking property is improved by changing the discharge angle of the document with respect to the paper discharge tray. The technique made into this is known (for example, refer patent document 1).

  In the document disclosed in Patent Document 1, a pair of paper discharge rollers is supported by a side plate as a single support member, and the nip angle (tangential angle) of the paper discharge roller pair is changed by rotating the side plate. Is configured to change the discharge angle.

  However, in the technique described in Patent Document 1, since the driving roller and the driven roller constituting the paper discharge roller pair are supported by the same support member, the paper discharge roller pair cannot be pressed. For this reason, when the paper discharge roller is worn, the sheet conveying force is reduced, and the durability is low.

  The present invention has been made to solve the above-described conventional problems, and can automatically improve the durability of a pair of paper discharge rollers while making the nip angle of the pair of paper discharge rollers variable. An object of the present invention is to provide an image reading apparatus and an image forming apparatus.

  The automatic document feeder according to the present invention includes a document stacking unit for stacking documents, a separation feeding unit for separating and feeding documents stacked on the document stacking unit one by one, and a separation feeding unit by the separation feeding unit. In the automatic document conveying apparatus, comprising: a conveying unit that conveys a fed document to a reading position; and a pair of discharge rollers that discharges the document conveyed to the reading position by the conveying unit to the outside of the apparatus. A pressure unit that presses one roller of the paper roller pair against the other roller, and an arc that supports the one roller and the pressure unit and that is centered on the other roller independently of the other roller. And a driving means for oscillating the oscillating member.

  According to the present invention, it is possible to provide an automatic document feeder, an image reading apparatus, and an image forming apparatus capable of improving the durability of a pair of paper discharge rollers while making the nip angle of the paper discharge roller pair variable.

1 is a schematic configuration diagram of an automatic document feeder and an image forming apparatus including the automatic document feeder according to an embodiment of the present invention. 1 is a configuration diagram of an automatic document feeder according to an embodiment of the present invention. FIG. 2 is a block diagram of a control system of the automatic document feeder according to the 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 an embodiment of the present invention. FIG. FIG. 4 is a perspective view showing a nip angle variable mechanism for a pair of paper discharge rollers of the automatic document feeder according to the embodiment of the present invention. FIG. 4 is a side view showing a nip angle variable mechanism for a pair of paper discharge rollers of the automatic document feeder according to the embodiment of the present invention. FIG. 6 is a side view showing the operation of the nip angle variable mechanism for the pair of paper discharge rollers of the automatic document feeder according to the embodiment of the present invention. 4 is a side view showing a configuration in which a guide plate is provided in a nip angle variable mechanism of a pair of paper discharge rollers of an automatic document feeder according to an embodiment of the present invention.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of an automatic document feeder and an image forming apparatus including the automatic document feeder according to an embodiment. FIG. 2 is a configuration diagram of the automatic document feeder according to the embodiment. FIG. 3 is a block diagram of a control system of the automatic document feeder according to the embodiment. 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 40 that conveys a document, and an image forming apparatus main body 70 a that reads a document and forms an image on a transfer sheet. . The automatic document feeder 40 is provided to be openable and closable with respect to the image forming apparatus main body 70a via a hinge mechanism (not shown).

  An image reading unit 81 is provided in the image forming apparatus main body 70a, and image information read by the image reading unit 81 is applied to the photosensitive drum 83 by the writing unit 82. A combination of the automatic document feeder 40 and the image reading unit 81 constitutes an image reading device 80.

  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 70a 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 40 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 that transports the topmost document from 1; paper feed belt 9 and reverse roller 10 that separates the document transported 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 A pair of discharge rollers 50 for discharging the conveyed document Ri, 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 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 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 40 includes a controller 100 that controls the entire automatic document feeder 40. The automatic document feeder 40 also includes a registration sensor 17, a document set sensor 5, a paper discharge sensor 24, a butting sensor 11, a document width sensor 13, a reading entrance sensor 15, A paper proper position sensor 8 and a home position sensor 6 are provided.

  Further, the automatic document feeder 40 is 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 ascending as an actuator or the like for driving and controlling by outputting a signal from the controller 100. A motor 105 is provided.

  The image forming apparatus main body 70a includes a main body control unit 111 that controls the image forming apparatus main body 70a, 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 illustrating the configuration of the image reading unit of the automatic document feeder according to the embodiment.

  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 40 will be described according to the order in which the document placed on the document table 2 is 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 70a 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 27a 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 the effective image area in the sub-scanning direction is transmitted until the trailing edge of the document 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 a predetermined 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 original 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 pair 50 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 immediately before the trailing edge of the original comes out of the nip region of the paper discharge roller pair 50. By reducing the driving speed of 104, the document discharged onto the discharge tray 29 is prevented from jumping 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.

  As shown in FIGS. 5 and 6, the paper discharge roller pair 50 is composed of a driving roller 50a and a driven roller 50b.

  The driving roller 50a is arranged on the upper side near the exit of the conveyance path, and a plurality (two in this embodiment) are provided side by side in the axial direction of the driving roller shaft 51a that is the rotation center axis.

  The drive roller 50a rotates integrally with the drive roller shaft 51a. The drive roller shaft 51a is rotatably supported by a housing or the like (not shown) and is driven to rotate by a drive source (not shown).

  The driven roller 50b is disposed below the vicinity of the exit of the conveyance path, and a plurality (two in the present embodiment) are provided side by side in the axial direction of the driven roller shaft 51b that is the rotation center axis thereof.

  The driven roller 50b rotates integrally with the driven roller shaft 51b. The driven roller shaft 51b is rotatably supported by driven roller bearings 52 provided at both ends thereof.

  The driven roller bearing 52 is supported by the swing bracket 53 and is pressed toward the drive roller 50 a by the pressure of a spring 57 provided on the swing bracket 53.

  That is, the spring 57 constitutes a pressurizing unit that pressurizes the driven roller 50b against the driving roller 50a to generate a nip pressure (pressure that presses against each other) between the driven roller 50b and the driving roller 50a.

  The swing bracket 53 is formed in a U-shape including two vertical portions 53a where the driven roller bearing 52 and the spring 57 are disposed, and a horizontal portion 53b connecting the two vertical portions 53a.

  The swing bracket 53 does not support the drive roller 50a, supports the driven roller 50b, and swings independently of the drive roller 50a.

  On the outer surface of the vertical portion 53a of the swing bracket 53, two guide pins 54 are provided on one side (four on both sides).

  The guide pin 54 is inserted through an arc-shaped slit 58 a formed in a support member 58 disposed outside the vertical portion 53 a of the swing bracket 53. When the guide pin 54 is inserted into the arc-shaped slit 58a, the swing bracket 53 is supported so as to be swingable in an arc shape by the support member 58, and the guide pin 54 hits the end of the slit 58a. With this, the swing range is regulated. The support member 58 is composed of, for example, a side plate that constitutes a casing of the automatic document feeder 40.

  The arc-shaped slit 58a formed in the support member 58 has a shape in which the position of the center of the arc coincides with the position of the drive roller shaft 51a of the drive roller 50a.

  For this reason, when the swing bracket 53 swings, the driven roller 50b supported by the swing bracket 53 swings on a concentric arc centering on the drive roller 50a.

  Therefore, when the swing bracket 53 swings, the distance between the drive roller 50a and the driven roller 50b is kept constant, so that the pressure applied by the spring 57 can be kept constant.

  An arcuate swing gear 55 is formed on the lower surface of the horizontal portion 53b of the swing bracket 53, and a drive gear 56 that meshes with the swing gear 55 is provided below the horizontal portion 53b.

  The drive gear 56 is connected to a drive source such as a motor (not shown) and swings the swing bracket 53 as shown in FIG.

  When the swing bracket 53 swings, the driven roller 50b supported by the swing bracket 53 swings on a concentric circular arc centered on the drive roller 50a. Therefore, the distance between the drive roller 50a and the driven roller 50b and While maintaining the nip pressure constant, the angle of the tangent line between the driving roller 50a and the driven roller 50b, that is, the nip angle changes, and the document discharge angle changes.

  Here, if the nip angle of the discharge roller pair 50 is changed in order to change the discharge angle of the original, the entry angle when the original enters the discharge roller pair 50 also changes, so the original enters the discharge roller pair 50. When doing so, the manuscript may be damaged.

  Therefore, as shown in FIG. 8, a guide plate 59 whose posture changes in accordance with a change in the nip angle of the paper discharge roller pair 50 is provided upstream of the paper discharge roller pair 50, whereby the nip of the paper discharge roller pair 50. The angle of entry of the document into the section can be kept constant.

  Specifically, in FIG. 8, on the upstream side of the paper discharge roller pair 50, the CIS exit roller pair 27 that transports the original to the paper discharge roller pair 50, and the original that is transported by the CIS exit roller pair 27 is discharged. A conveyance guide 60 that guides the roller pair 50 is provided.

  The CIS exit roller pair 27 includes a CIS exit roller 27a positioned on the upper side of the transport path and a CIS exit facing roller 27b positioned on the lower side of the transport path and pressed against the CIS exit roller 27a. Moreover, the conveyance guide 60 is comprised from the upper side guide plate 60a located in the upper side of a conveyance path | route, and the lower side guide plate 60b located in the lower side of a conveyance path | route.

  A guide plate 59 that guides the leading edge of the document conveyed to the vicinity of the discharge roller pair 50 to the nip portion of the discharge roller pair 50 is fixed to the upstream end of the swing bracket 53. The guide plate 59 swings integrally with the swing bracket 53.

  When the guide plate 59 is viewed from the side as shown in FIG. 8, the upstream end is disposed in the vicinity of the downstream side of the lower guide plate 60b of the upstream conveyance guide 60, and the downstream end is discharged. The shape is arranged in the vicinity of the nip portion of the roller pair 50.

  The guide plate 59 can also be regarded as being fixed to the swing bracket 53 by cutting the downstream end of the lower guide plate 60 b of the conveyance guide 60.

  As described above, when the guide plate 59 is fixed to the upstream end of the swing bracket 53 to swing the swing bracket 53 and change the nip angle of the paper discharge roller pair 50, the guide along with the swing bracket 53 is guided. Since the plate 59 also swings, the document can be guided to the nip portion at the same angle before and after the change of the nip angle of the discharge roller pair 50, and the entrance angle of the document to the nip portion can be kept constant.

  Regardless of the swing angle of the swing bracket 53, it is preferable that the upstream end of the guide plate 59 be in a position where the document can be guided. Therefore, in the present embodiment, when the swing bracket 53 swings to the clockwise end position in FIG. 8, the position of the upstream end portion of the guide plate 59 is the lower guide of the upstream transport guide 60. The shape of the guide plate 59 is set so as to be the same height as the downstream end portion of the plate 60b, or the mounting posture of the guide plate 59 to the swing bracket 53 is set.

  As described above, the automatic document feeder 40 according to the present embodiment includes the document table 2 on which documents are stacked, the paper feed belt 9 and the reverse roller that separate and feed the documents stacked on the document table 2 one by one. 10, a pull-out roller 12, an intermediate roller 14, a reading inlet roller 16, a reading roller 19 for conveying a document separated and fed by the paper feeding belt 9 and the reverse roller 10 to a reading position 20, and a reading position 20 by these rollers. A pair of paper discharge rollers 50 for discharging the original conveyed to the outside of the apparatus, a spring 57 for pressing one driven roller 50b of the paper discharge roller pair 50 against the other driving roller 50a, and a driven roller 50b. A swing bracket 53 that supports a spring 57 and swings on an arc centered on the drive roller 50a independently of the drive roller 50a; A drive gear 56 for oscillating movement bracket 53, and further comprising a.

  With this configuration, when the swing bracket 53 swings, the distance between the drive roller 50a and the driven roller 50b can be kept constant and the pressure applied by the spring 57 can be kept constant. The wear can be prevented and the durability can be improved. Therefore, the durability of the paper discharge roller pair 50 can be improved while the nip angle of the paper discharge roller pair 50 is variable.

  The automatic document feeder 40 according to the present embodiment is provided on a swing bracket 53 and swings integrally with the swing bracket 53, and guides the document to the nip portion of the paper discharge roller pair 50. A plate 59 is provided.

  With this configuration, the nip angle of the paper discharge roller pair 50 can be changed without changing the angle of entry of the original into the nip portion of the paper discharge roller pair 50, so that the original touches the paper discharge roller pair 50 and is damaged. It can be prevented from receiving.

  Further, the image reading apparatus 80 according to the present embodiment includes the automatic document feeder 40 described above.

  With this configuration, in the image reading apparatus 80 including the automatic document feeder 40, it is possible to improve the durability of the paper discharge roller pair while making the nip angle of the paper discharge roller pair variable.

  In addition, an image forming apparatus according to the present embodiment includes the automatic document feeder 40 described above.

  With this configuration, in the image forming apparatus 70 including the automatic document feeder 40, it is possible to improve the durability of the discharge roller pair while changing the nip angle of the discharge roller pair.

  As described above, the automatic document feeder, the image reading apparatus, and the image forming apparatus according to the present invention can improve the durability of the discharge roller pair while making the nip angle of the discharge roller pair variable. This is effective, and is useful as an automatic document conveying device that separates one document from a document bundle and conveys it to a reading position, and an image reading device and an image forming apparatus provided with this automatic document conveying device.

2 Document table (document stacking means)
9 Feeding belt (separate feeding means)
10 Reverse roller (separate feeding means)
12 Pull-out roller (conveying means)
14 Intermediate roller (conveying means)
16 Reading entrance roller (conveying means)
19 Reading roller (conveying means)
20 Reading Position 25 Second Reading Unit 27 CIS Exit Roller Pair 27a CIS Exit Roller 27b CIS Exit Opposing Roller 29 Paper Discharge Tray 40 Automatic Document Feeder 50 Paper Discharge Roller Pair 50a Drive Roller (Other Roller)
50b Follower roller (one roller)
51a Drive roller shaft 51b Driven roller shaft 52 Driven roller bearing 53 Oscillating bracket (oscillating member)
53a Vertical portion 53b Horizontal portion 54 Guide pin 55 Oscillating gear 56 Drive gear (drive means)
57 Spring (Pressurizing means)
58 support member 58a slit 59 guide plate (guide member)
60 Transport Guide 60a Upper Guide Plate 60b Lower Guide Plate 70 Image Forming Apparatus 70a Image Forming Apparatus Main Body 80 Image Reading Apparatus 81 Image Reading Unit

Japanese Patent No. 2880817

Claims (4)

A document loading means for loading a document;
Separation feeding means for separating and feeding the documents stacked on the document loading means one by one;
Transport means for transporting the document separated and fed by the separation feeding means to a reading position;
An automatic document feeder comprising: a pair of discharge rollers for discharging the document conveyed to the reading position by the conveyance means to the outside of the apparatus;
Pressurizing means for pressurizing one roller of the paper discharge roller pair to the other roller;
A swinging member that supports the one roller and the pressure unit, and swings on an arc centered on the other roller independently of the other roller;
An automatic document feeder comprising: drive means for swinging the swing member.   2. The automatic apparatus according to claim 1, further comprising a guide member that is provided on the swing member, swings integrally with the swing member, and guides a document to a nip portion of the discharge roller pair. Document transport device.   An image reading apparatus comprising the automatic document feeder according to claim 1.   An image forming apparatus comprising the automatic document feeder according to claim 1.

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