JP4017939B2 - Automatic document feeder and image reading apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an automatic document feeder and an image reading apparatus that are compatible with a sheet-through method in which a reading unit is fixed and a document is conveyed while being conveyed.
[0002]
[Prior art]
Conventionally, in this type of automatic document feeder, a document is conveyed as shown in FIGS. First, as shown in FIG. 10, a sheet-like document (not shown) on the bottom plate 4 b is called by the calling roller 5 and separated one by one, and then the contact glass 101 is set by the first conveying roller pair 8 and 9. Transport to the upper reading position (first transport path R₁), After reading the first surface (front surface) of the document, the second conveyance path R is formed by the second conveyance roller pair 14 and 15 and the discharge roller pair 16 and 17.₂The third transport path R is transported by the switching claw 190.₃The paper is conveyed to the upper reversing roller pair 21 and 22 and the original after surface reading is held on the reversing table 23. Next, as shown in FIG. 11, the original is moved to the third transport path R.₃Switch-back transport is performed above, and the fourth transport path R is further switched by the switching claw 190.₄Guide you up. Next, as shown in FIG. 12, the original is again conveyed to the reading position on the contact glass 101 by the first conveying roller pair 8 and 9, and after reading the second surface (back side) of the original, the second conveyance is performed. The second transport path R is formed by the roller pairs 14 and 15 and the paper discharge roller pairs 16 and 17.₂The third transport path R is transported by the switching claw 190.₃It is guided to the upper reversing roller pair 21, 22 and further conveyed onto the reversing table 23. Next, as shown in FIG. 13, in order to arrange the discharge order of the originals after the double-sided reading, the third transport path R₃The above document is switched back and the fourth transport path R is again₄, First transport path R₁, Second transport path R₂Through the paper discharge tray 20.
The devices related to this type are described in JP-A-9-166896 and JP-A-10-81449. Here, two switching claws are provided to reduce the number of passes of the reading position in double-sided reading.
[0003]
[Problems to be solved by the invention]
However, the conventional automatic document feeder has a problem in that it is difficult to shorten the conveyance time in the double-sided reading because the originals after the double-sided reading are aligned again by being conveyed to the reading position and reversed. . Further, when two switching claws are provided to reduce the number of times of passage of the document after double-sided scanning, there is a problem that the configuration is complicated although the processing efficiency is improved.
The present invention has been made to solve such a problem, and provides an automatic document conveying device and an image reading device capable of reducing the time required for the reading and conveying operation with a simple configuration.
[0004]
[Means for Solving the Problems]
  As a reference, the present inventionThe automatic document transport device includes a transport unit that transports a document, and a paper discharge tray for discharging the document after being read at the reading position, and the retreat position for retracting the read position and the document after the reading. 1 is a first guide surface for guiding a document after one-side reading on the retracting path from the reading position toward the sheet discharge table. A second guide surface that guides a document after reading on both sides on the retraction path from the reading position toward the retraction position; and a document after reading on both sides on the retraction path from the retraction position. And a third guide surface that guides toward the paper discharge tray, and has a configuration that includes switching means for switching the guide direction so that one of the first to third guide surfaces is in contact with the document being conveyed. is doing.
  With this configuration, when a document to be scanned on both sides is transported, when the document after duplex scanning is discharged, the document is directly discharged from the third guide surface of the switching means without passing the reading position on the contact glass. Thus, the document discharge processing time can be shortened. In addition, since one switching means having the first to third guide surfaces is used, the configuration is simplified and an inexpensive automatic document feeder can be provided.
[0005]
  Claim 1An automatic document feeder according to the present invention includes a document placement table on which a document is placed, a paper discharge table below the document placement table for stacking documents after being read at a reading position, and the document Separating means that separates the originals on the mounting table one by one and conveys them to the reading position, and conveys the originals that have been read at the reading position to the retracted position and is opposite to the conveying direction toward the retracted position And a retracting means for switching back and transporting, the first conveying path communicating the separating means and the reading position, and the reading position and the retracted position of the document after being read at the reading position. An automatic document conveying device in which a second conveying path and a third conveying path that communicates the retracted position and the reading position are formed between the document placing table and the discharge table, By the retraction means, the original after reading one side is The first guide surface that guides the original after one-side reading on the second conveyance path and the original after double-side reading from the reading position by the retracting means when the original is transported from the take-off position to the discharge table. When transporting the original after double-sided reading on the second transport path when transporting to the retracted position, and by switchback transporting the original after single-sided scanning from the retracted position to the read position by the retracting means In addition, the second guide surface that guides the original after one-side reading on the third conveyance path and the retracting means switchback-convey the original after double-sided reading from the retracted position toward the discharge table. And a third guide surface for guiding the document after reading on both sides on the second conveyance path. When reading a document on both sides, the document after reading on both sides is guided in the retracting direction by the second guide surface. Then to be guided to the paper discharge direction by the third guide surface, switches the guiding directionA switching means; a reverse drive roller that is reversely driven when switchback transporting the document retracted to the retracted position on the second transport path; and a reverse driven roller that is driven in contact with the reverse drive roller. The switching means is provided so as to be rotatable about the shaft of the reverse driven roller.It has a configuration.
  With this configuration, when a document to be scanned on both sides is transported, when the document after duplex scanning is discharged, the document is first guided in the retracting direction by the second guide surface of the switching means and then discharged by the third guide surface. Since the paper is guided in the paper direction, it is not necessary to pass the reading position on the contact glass, and the document discharge processing time can be shortened. In addition, since one switching means having the first to third guide surfaces is used, the configurationButA simple and inexpensive automatic document feeder can be provided.
  Further, with this configuration, the original after double-sided reading is guided by the third guide surface of the switching unit and is nipped and conveyed by the reverse driving roller and the reverse driven roller, so that an original thicker than a predetermined thickness can be reliably discharged. I can make paper.
[0007]
  Also,For reference, the automatic document feeder according to the present invention includesThe switching means is provided with a driven roller that comes in contact with and separates from the outer peripheral surface of the reversing drive roller in accordance with the rotation of the switching means, and when conveying the original after reading both sides from the retracted position to the paper discharge table, The driven roller has a configuration in contact with the outer peripheral surface of the reverse drive roller.
  With this configuration, the original after double-sided reading is guided by the third guide surface of the switching unit, and is further nipped and conveyed by the reverse drive roller, the reverse driven roller, and the driven roller. Thus, the stackability at the time of paper discharge can be improved.
[0008]
  Also,For reference, the automatic document feeder according to the present invention includesWhen a document after duplex reading is transported from the retracted position to the paper discharge tray, document detection means is provided for detecting the trailing edge of the document in the transport direction, and the next document reading start timing is detected based on detection information of the document detection means. Is determined.
  With this configuration, since the reading timing of the next original can be accurately determined using the detection information of the original detection means, the processing time of the entire reading and conveying operation can be shortened.
[0009]
  Also,For reference, the automatic document feeder according to the present invention includesThe position of the original discharged on the paper discharge tray is different between when reading one side and when reading both sides.
  With this configuration, when single-sided scanning is performed after double-sided scanning, the position of the discharged document is different, so that the document after single-sided scanning hits the end surface of the document after double-sided reading remaining on the paper discharge table. Can be avoided.
[0010]
  further,Claim 2The image reading apparatus of the present invention according toClaim 1The automatic document transport device described above is provided, and at least a sheet-through method that reads while transporting a document, and includes a setting unit that sets a single-side mode for reading one side of a document and a duplex mode for reading both sides of a document. is doing.
  With this configuration, as described above, the time required for the reading and conveying operation including the paper discharge processing time is shortened, so that the processing speed of the image reading apparatus is improved.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows a configuration of an image reading apparatus according to an embodiment of the present invention. FIG. 2 shows a case where a document is set on an automatic document feeder (hereinafter also referred to as ADF) mounted on the image reading apparatus.
[0012]
In FIG. 1, the ADF 300 is connected to the main body 200 of the image reading apparatus by a hinge or the like so as to be opened and closed, and is mounted on a contact glass on the upper part of the main body 200. The ADF 300 is configured to be compatible with a sheet-through method in which the document 1 is conveyed to a reading position on the contact glass 101 and the reading unit 10 is fixed and read in the ADF mode. The reading unit 10 includes a light source, a mirror, a lens, an image sensor (for example, a charge coupled device (CCD)), and the like. In the ADF 300, the paper discharge tray 20 is provided below the document table 2. Furthermore, the first transport path R₁, Second transport path R₂, Third transport path R₃, Fourth transport path R₄Is provided below the document table 2 and above the paper discharge tray 20 (included in the paper discharge unit).
[0013]
The document table 2 has a bottom plate 4b that can move up and down, and is used to place a sheet-shaped document 1 (shown in FIG. 2). Further, the document table 2 is provided with a width size detection board 121 for detecting the width size of the document 1 placed thereon, and document length sensors 30 and 31 for detecting the length. The calling roller 5 takes out the document 1 on the document table 2 from the top and sends it to the separation unit (including the sheet feeding belt 6 and the separation roller 7). The separating unit separates the documents taken out from the document table 2 by the calling roller 5 one by one, and the first transport path R₁To send to. The separation unit is unitized as a guide member 50 that also serves as a paper feed belt 6, a separation roller 7, and an exterior cover.
[0014]
First transport path R₁The first conveyance driving roller 8, the first conveyance driven roller 9, the registration sensor 12, the reflection guide plate 11, the second conveyance driving roller 14, the second conveyance driven roller 15 and the like are arranged. Second transport path R₂A paper discharge sensor 24, a paper discharge driving roller 16, a first paper discharge driven roller 17, a switching claw 19 and the like are arranged. Third transport path R₃Forms a switchback path for retracting the document 1 after image reading to the reversing table 23 and transporting it again to the reading position in the direction opposite to the retracting direction. The third transport path R₃Are arranged with a reverse drive roller 32, a first reverse driven roller 33, a reverse table 23, a reverse sensor 35, and the like. Fourth transport path R₄A paper discharge driving roller 16, a second paper discharge driven roller 18 and the like are arranged. Further, a second reverse driven roller 31a (included in the reverse driven roller) and a third reverse driven roller 31b are included in the conveyance path formed between the guide surface 19c of the switching claw 19 and the outer peripheral surface of the reverse drive roller 32. (Included in the driven roller) is arranged. The third reverse driven roller 31 b is rotatably attached to the switching claw 19.
[0015]
As shown in FIGS. 3 and 4, the switching claw 19 is rotatably supported by the shaft of the first reverse driven roller 31a, and rotates around the axis by driving the switching claw solenoid 112 (included in the switching means). It is configured to move from the home position (position A) to position B. Here, the original after the first side reading and the both side reading in the duplex mode is transferred to the first transport path R.₁, Second transport path R₂3rd transport path R through₃When the switching claw solenoid 112 is driven, the switching claw 19 is moved from the home position to the position B, and the document is conveyed on the first guide surface 19a. In addition, the third transport path R in the duplex mode₃When the original after double-sided reading held on the reversing table 23 is conveyed to the paper discharge tray 20, the switching claw solenoid 112 is driven to move the switching claw 19 from the home position to the position B. The original is discharged along the guide surface 19c. Further, the original after reading the first side in the single-side mode is transferred to the first transport path R.₁, Second transport path R₂When the paper is conveyed to the paper discharge tray 20, the switching claw 19 is at the home position by releasing the switching claw solenoid 112, and the original is discharged along the guide surface 19b. As shown in FIG. 5, the paper discharge direction (shown by arrow 42) when discharged in the single-side mode is different from the paper discharge direction (shown by arrow 43) when discharged in the double-side mode. Therefore, the discharge positions on the discharge tray 20 are also different. For example, when the discharge operation in the single-sided mode and the discharge operation in the double-sided mode are performed before and after, the respective discharged originals are discharged to the discharge tray 20a, It is possible to avoid the damage due to overlapping or hitting at 20b.
[0016]
Next, the control part of this embodiment is demonstrated using FIG.
The main body 200 of the image reading apparatus according to the present embodiment includes a main body control unit 212 that controls the entire apparatus, and the main body control unit 212 uses the controller 100 (settings) of the ADF 300 via communication means (for example, a serial communication line). A signal transmitted from (included in the means) is received. The main body control unit 212 performs drive control of the reading unit 10, display control in the operation unit 211, and the like based on information indicated by the signals received and input in this manner, and also transmits a mode signal and paper feed to the controller 100. Various control signals including a start signal (start signal) are transmitted, and the controller 100 is instructed to control the transport operation of the ADF 300. Further, in the RAM (not shown) of the main body control unit 212, the operation mode input and set from the operation unit 211 (included in the setting unit) of the main body 200 is stored in an updatable manner, and the contents are changed each time the content is changed. The stored contents are updated.
[0017]
In addition, the operation unit 211 includes various button keys such as a start button and a numeric keypad (not shown), an LCD display, and the like, so that mode setting and operation start / stop instructions can be performed by a user operation. Has been. In the present embodiment, at least an ADF mode in which the ADF 300 is closed and the document 1 on the document table 2 is automatically conveyed, a single-side mode in which one side of the document 1 is read in this ADF mode, and a double-side mode in which both sides of the document 1 are read. It can be set.
[0018]
The controller 100 that controls the operation of the ADF 300 includes a detection signal from each sensor including the registration sensor 12, the document set sensor 4, the document length sensors 30 and 31, the paper discharge sensor 24, and the reverse sensor 35, and a paper feed motor 102. , A status signal from each motor including the reading motor 103, the reversing motor 107, and the bottom plate raising motor 105, a status signal from the switching claw solenoid (SOL) 112, and a control signal (via a communication means with the main body 200). Input a paper feed start signal). The controller 100 transmits detection information from the sensor and the like to the main body control unit 212 on the main body 200 side, and controls driving of the motor and the like based on a control signal transmitted from the main body control unit 212.
[0019]
In addition, since each of the motors is composed of a stepping motor, for example, the driving amount can be easily obtained by counting the number of pulses and multiplying by the driving amount per pulse, and based on the driving amount and each sensor information. In addition to detecting the document length, it is possible to perform transport interval (paper interval) control between the preceding document and the next document, read position arrival timing control after registration detection, read operation end timing control, and the like.
[0020]
Here, the drive part of this embodiment is demonstrated.
When the paper feed motor 102 is driven, the drive of the paper feed motor 102 is transmitted to the rotation shaft of the paper feed belt 6 through a plurality of pulleys and gears (not shown), and further, a plurality of pulleys (not shown) from the paper feed belt 6; It is transmitted to the rotating shaft of the calling roller 5 through the gear and the timing belt. Further, the driving force of the paper feed motor 102 is transmitted to the separation roller 7 via a plurality of pulleys, gears, and timing belts (not shown).
[0021]
When the reading motor 103 is driven, the driving of the reading motor 103 is transmitted to the rotation shafts of the first conveyance driving roller 8 and the second conveyance driving roller 14 through a plurality of pulleys and timing belts (not shown). The driving of the reading motor 103 is transmitted to the paper discharge driving roller 16 via a plurality of pulleys and timing belts (not shown).
[0022]
When the reverse motor 107 is driven, as shown in FIG. 7, the reverse motor 107 is driven from a pulley 347 provided on the shaft of the reverse motor 107 to a pulley 348 provided on the shaft of the reverse drive roller 32 by a timing belt. Communicated.
[0023]
Next, the document conveyance and reading operations according to the present embodiment will be described with reference to FIG.
First, the user places the document 1 on the document table 120 with the first surface (front surface) facing upward. Here, the leading edge of the document is positioned by abutting against the paper feed guide plate 3. The bottom plate 4b is rotated about a fulcrum 4a by driving a solenoid (not shown), and pushes up the calling roller 5 by the document 1 on the bottom plate 4b. The calling roller 5 pressurizes the document 1 by raising the bottom plate 4b, sequentially takes out from the uppermost document by a start signal from the main body 200, and sends it to a separation unit (including the sheet feeding belt 6 and the separation roller 7) ( Step S101). The original separated one by one by the separation unit is a first conveyance path R in which a first conveyance driving roller (also referred to as a pull-out roller) 8 and a first conveyance driven roller 9 are arranged.₁Then, the sheet is conveyed to a reading position on the contact glass 101. At this reading position, the first surface of the document is read by the reading unit 10 on the main body 200 side while being conveyed between the reflection guide plate 11 and the contact glass 101.
[0024]
Here, in the case of single-sided reading (single-sided mode), the first side of the original 1 is read by the reading unit 10 as described above (one side of step S102, S103). 2nd conveyance path R in which the 2 conveyance drive roller 14, the 2nd conveyance driven roller 15, the paper discharge drive roller 16, and the 1st paper discharge driven roller 17 are arrange | positioned.₂Then, the sheet is conveyed to the discharge tray 20 and stacked (steps S104 to S106). In this case, the switching claw 19 is at the home position (position A), and the document 1 is guided by the guide surface 19b.
[0025]
Note that the conveyance drive rollers (including the first conveyance drive roller 8 and the second conveyance drive roller 14), the registration sensor 12, the paper discharge sensor 24, the reverse sensor 35, the switching claw 19, and the reverse drive roller 21 in the case of single-sided reading. The operation timing and document reading timing are as shown in FIG.
[0026]
In the case of double-sided reading (double-sided mode), the first side of the original 1 is read as described above (both sides in step S102, S107), and the original 1 after reading the first side is read by the second conveyance described above. Road R₂3rd transport path R through₃It is conveyed to. When the leading edge of the document is detected by the paper discharge sensor 24, the switching claw 19 is lowered from the home position to the position B by driving the switching claw solenoid (SOL) 112. By this lowering operation, the document 1 is fed to the third conveyance path R in which the reverse driving roller 32 and the first reverse driven roller 33 are arranged.₃It is conveyed onto the reversing table 23 through (forming a switchback path). Further, after a predetermined time has elapsed after the trailing edge of the document is detected by the paper discharge sensor 24, the switching claw 19 returns from the position B to the home position by releasing the switching claw solenoid 112. The predetermined time here is a time until the trailing edge of the document passes through the paper discharge driving roller 16 and the first paper discharge driven roller 17 and reaches the switching claw 19.
[0027]
Next, as described above, after the switching claw 19 returns to the home position, the reverse driving roller 32 is driven in the reverse direction, and the original 1 that has been retracted to the switchback path includes the paper discharge driving roller 16 and the second paper discharge driven roller. 4th conveyance path R where 18 is arranged₄Enter. Here, since the paper discharge driving roller 16 has been stopped for a preset time, the leading edge of the document abuts against the nip portion between the paper discharge driving roller 16 and the second paper discharge driven roller 18, and skew correction (abutment). Correction) is made. After completion of the abutting correction, the document 1 after reading the first surface is transferred to the fourth transport path R.₄, First transport path R₁Then, the image is conveyed to a reading position on the contact glass 101, and an image on the second surface (back surface) is read by the reading unit 10 (steps S108 and S109). As described above, the document 1 after both sides are read in this way is the second transport path R.₂3rd transport path R through₃It is conveyed to. Here, when the leading edge of the document is detected by the paper discharge sensor 24, the switching claw 19 is lowered from the home position to the position B by driving the switching claw solenoid 112. By this lowering operation, the document 1 is guided to the guide surface 19a, and the third conveyance path R in which the reverse driving roller 32 and the first reverse driven roller 33 are arranged.₃And is conveyed onto the reversing table 23. Further, the reverse driving roller 32 stops in a state where the rear end of the document is nipped between the reverse driving roller 32 and the first reverse driven roller 33. Here, the switching claw 19 is held at the position B as described above.
[0028]
Next, by the reverse drive of the reverse drive roller 32, the document 1 passes between the guide surface 19c of the switching claw 19 and the reverse drive roller 32 and is sequentially guided to the second reverse driven roller 31a and the third reverse driven roller 31b. Then, it is further conveyed to the paper discharge tray 20 and discharged (steps S110 to S112). By such a paper discharge operation, the page order can be aligned so that the first surface of the document 1 is stacked face down. It should be noted that when the rear end of the original 1 after double-sided reading is detected by the reverse sensor 35 (included in the original detection means) at the time of switchback conveyance, the next original reading operation waiting in the vicinity of the reading position in advance is performed. Is started. Further, after the reading operation of the next original is started, the switching claw 19 returns from the position B to the home position by releasing the switching claw solenoid 112.
[0029]
Note that the conveyance drive rollers (including the first conveyance drive roller 8 and the second conveyance drive roller 14), the registration sensor 12, the paper discharge sensor 24, the reverse sensor 35, the switching claw 19, and the reverse drive roller 21 in the case of duplex scanning. The operation timing and document reading timing are as shown in FIG.
[0030]
As described above, the automatic document feeder 300 according to the embodiment of the present invention includes the document table 2 (contained in the document table) on which the document is placed, and the document table 2 below the document table 2 for reading. A sheet discharge tray 20 (included in the sheet discharge tray) for stacking documents after being read at the position and a separation unit (conveying means, separation unit) for separating the documents on the document table 2 one by one and conveying them to the reading position. And the reversal of conveying the document after being read at the reading position onto the reversing table 23 (included in the retracted position) and switchback conveyance in the direction opposite to the conveying direction toward the reversing table 23. A first transport path R that includes a driving roller 32 and a first reverse driven roller 33 (included in the transport unit and the retracting unit) and communicates the separation unit and the reading position.₁(Contained in the first conveyance path) and the second conveyance path R that communicates the reading position and the reversing table 23.₂And the third transport path R₃(Included in the retreat path, the second transport path) and the second transport path R₂A fourth transport path R that communicates the reversing table 23 with the reading position above₄(Included in the third conveyance path) is an automatic document conveyance device formed in a loop between the document table 2 and the paper discharge tray 20, and includes a reverse driving roller 32 and a first reverse driven roller 33. Thus, when the original after single-sided reading is transported from the reading position to the paper discharge tray 20, the third transport path R₃A reversing table for reading a document after reading on both sides from a reading position by a guide surface 19b (included in the first guide surface) for guiding the document after reading on one side and a reverse driving roller 32 and a first reverse driven roller 33. When transporting to 23, the second transport path R₂And the third transport path R₃The third conveyance path is used to guide the original after the double-sided reading on the upper side and switch-back convey the original after the single-sided reading from the reverse table 23 to the reading position by the reverse driving roller 32 and the first reverse driven roller 33. R₃The original after the double-sided reading is discharged from the reversing table 23 by the guide surface 19a (included in the second guiding surface) for guiding the original after the one-side reading, and the reverse driving roller 32 and the first reverse driven roller 33. When switchback conveyance is performed toward the paper tray 20, the third conveyance path R₃And a guide surface 19c (included in the third guide surface) for guiding the document after the double-sided reading. When reading the double-sided document, the document after the double-sided reading is guided in the retracting direction by the guide surface 19a, Next, since the switching claw 19 (included in the switching unit) for switching the guide direction is provided so that the guide surface 19c guides in the paper discharge direction, the document 1 after the double-sided reading retracted to the reversing table 23 is stored in one. Paper can be discharged without passing through the reading position by the switching operation of the switching claw.
[0031]
【The invention's effect】
As described above, according to the present invention, three guide surfaces are provided in one switching means (including a switching claw) of the automatic document feeder, and both sides are on the retreat path (including the third conveyance path) when reading both sides. The document after reading is guided from the retracted position (including the reversing table) toward the paper discharge tray (including the paper discharge tray), and discharged without passing through the reading position, thereby discharging the document with a simple configuration. It is possible to provide an automatic document feeder having an excellent effect of shortening the processing time.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a main part of an image reading apparatus (before setting a document) according to an embodiment of the present invention.
FIG. 2 is a cross-sectional view illustrating a main part of an image reading apparatus (when a document is set) according to an embodiment of the present invention.
FIG. 3 is an explanatory diagram illustrating a switching claw driving method according to an embodiment of the present invention.
FIG. 4 is an explanatory diagram illustrating the shapes of a switching claw and a reverse driving roller according to an embodiment of the present invention.
FIG. 5 is an explanatory diagram illustrating a paper discharge direction by a switching claw according to an embodiment of the present invention.
FIG. 6 is a block diagram illustrating a control unit of the image reading apparatus according to the embodiment of the present invention.
FIG. 7 is a perspective view showing a drive unit of a reverse drive roller according to an embodiment of the present invention.
FIG. 8 is a flowchart showing a reading and conveying method according to an embodiment of the present invention.
FIG. 9 is a timing chart showing a read transport operation according to an embodiment of the present invention.
FIG. 10 is a first explanatory diagram illustrating a transport operation by a conventional automatic document feeder.
FIG. 11 is a second explanatory diagram illustrating a transport operation by a conventional automatic document transport device.
FIG. 12 is a third explanatory diagram for explaining a conveying operation by a conventional automatic document feeder.
FIG. 13 is a fourth explanatory diagram for explaining a conveying operation by a conventional automatic document feeder.
[Explanation of symbols]
1 Manuscript
2 Original table
3 Paper feed guide plate
4 Document set sensor
4a fulcrum
4b Bottom plate
5 Calling roller
6 Paper feed belt
7 Separation roller
8 First transport drive roller
9 First transport driven roller
10 Reading unit
11 Reflection guide plate
12 Registration sensor
14 Second transport drive roller
15 Second transport driven roller
16 Discharge drive roller
17 First discharge driven roller
18 Second paper discharge driven roller
19 Switching claw
19a, 19b, 19c Guide surface
20, 20a, 20b Paper discharge tray
23 Inversion table
24 Paper discharge sensor
30, 31 Document length sensor
31a Second reverse driven roller
31b Third reverse driven roller
32 Reverse drive roller
33 First reverse driven roller
35 Reversing sensor
50 Guide members
101 Contact glass
121 width size detection board
200 Automatic document feeder (ADF)
300 Body of image reading apparatus

Claims (2)

A document placement table on which the document is placed, a paper discharge table below the document placement table on which the document after reading at the reading position is stacked, and a document on the document placement table are separated one by one. Separating means for transporting to the reading position, and retracting means for transporting the document after being read at the reading position to the retracted position and switchback transporting in a direction opposite to the transport direction toward the retracted position, A first conveyance path that communicates the separation unit and the reading position; a second conveyance path that communicates the reading position and a retracted position of the document after being read at the reading position; and a second conveyance An automatic document conveying device in which a third conveying path that communicates the retracted position and the reading position above the path is formed in a loop shape between the document placing table and the sheet discharging table,
A first guide surface that guides the original after one-side reading on a second conveyance path when the original after one-side reading is conveyed from the reading position to the discharge table by the retracting means, and the retracting means Thus, when the original after double-sided reading is conveyed from the reading position to the retracted position, the original after double-sided reading is guided on the second conveyance path, and the original after single-sided reading is guided by the retracting means. When the switchback conveyance is performed from the retreat position to the reading position, the second guide surface that guides the original after one-side reading on the third conveyance path and the retreating means allow the original after double-sided reading to be at the retraction position. And a third guide surface for guiding the document after reading on both sides on the second transport path when switchback transporting from the paper tray to the paper discharge table. As draft is guided to the withdrawal direction by the second guide surface, and then guided to the paper discharge direction by the third guide surface, and a switching means for switching the guide direction,
A reverse driving roller that is reversely driven when switchback transporting the document retracted to the retracted position on the second transport path;
A reverse driven roller driven in contact with the reverse drive roller;
Provided,
An automatic document feeder, wherein the switching means is rotatably provided on the shaft of the reverse driven roller . A setting means for setting a single-side mode for reading one side of a document and a double-side mode for reading both sides of a document in a sheet-through system that reads at least a document while conveying the automatic document conveyance device according to claim 1. An image reading apparatus characterized by that.

Images