JP3825931B2 - Automatic document feeder and image forming apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an automatic document feeder that transports a set original to a predetermined position and discharges it, and an image forming apparatus including the same.
[0002]
[Prior art]
Many of today's copying machines, scanners, and the like are equipped with an automatic document feeder (ADF) that automatically separates and feeds a plurality of documents one by one when they are set. The automatic document feeder sets a document on a document tray, separates and feeds the document one by one by a document feeding unit, and conveys the document to a predetermined position on a platen glass by a document conveying unit constituted by a conveyance belt. The original image is read by the reading device. Then, the document after image reading is transported to a document discharge unit by a transport belt, and is discharged to a document discharge tray or the like by the document discharge unit.
[0003]
Such an automatic document feeder is provided with a plurality of document paths from document feeding to discharge, and sequentially transports the respective paths. When the document is conveyed, a detection sensor detects whether or not the document has passed a predetermined position and controls the document conveyance amount.
[0004]
[Problems to be solved by the invention]
However, in the apparatus having a plurality of paths as described above, it is necessary to provide a large number of sensors in order to detect whether or not there is a document at a predetermined position in each path. For this reason, the number of sensors is increased, the number of parts and the number of assembly steps are increased, which increases the cost.
[0005]
The present invention has been made in view of the above points, and an object thereof is to provide an automatic document feeder and an image forming apparatus capable of reducing the cost by reducing the number of document detection sensors.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, a typical configuration according to the present invention includes a plurality of document paths and a plurality of document paths for conveying a document in an automatic document conveyance device that conveys and discharges a set document to a predetermined position. A detection sensor for detecting a document, and configured to detect the presence or absence of a document passing through a plurality of document paths by one detection sensor, The plurality of document paths are provided in a document feeding unit, a feeding path for transporting a document from the document feeding unit to the document transport unit, and a duplex reversing path for transporting the document when reading both sides of the document. When the detection sensor is composed of an optical sensor and the optical path of the optical sensor is provided in a guide member that separates the feeding path and the double-sided reversing path, and a plurality of documents are continuously fed in the duplex scanning mode. The subsequent document is set to wait at a position where the sensor optical path is not blocked. It is characterized by that.
[0007]
In the above configuration, by sharing a sensor for detecting a document passing through each path, it is not necessary to provide a sensor for each path. For this reason, the number of sensors can be reduced, the number of parts can be reduced, and the cost can be reduced.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Next, an image forming apparatus including an automatic document feeder according to an embodiment of the present invention will be specifically described with reference to the drawings.
[0009]
FIG. 1 is an explanatory diagram of the internal configuration of a copying machine as an example of an image forming apparatus equipped with an automatic document feeder. This copying machine is configured by connecting an automatic document feeder B to the upper part of an image forming apparatus main body A. ing.
[0010]
Here, the overall configuration of the image forming apparatus will be briefly described first, and then the automatic document feeder will be described in detail.
[0011]
[Entire configuration of image forming apparatus]
The image forming apparatus main body A integrally includes a reading device A1 and a recording device A2, and sequentially feeds a plurality of originals set on the automatic document feeder B and reads them by the reading device A1. According to the read information, recording is performed on a recording medium such as plain paper or an OHP sheet by the recording apparatus A2.
[0012]
The reading device A 1 irradiates the original G, which is conveyed to a predetermined position on the platen glass 1 by the automatic original conveying device B, which will be described in detail later, with light from the light source 2, and reflects the reflected light through the mirror 3 and the lens 4. Then, image exposure is performed on the photosensitive drum.
[0013]
The recording device A2 records an image on the recording medium S by electrophotography in accordance with the image exposure from the reading device A1. The specific structure of the image forming means is that the surface of the photosensitive drum 5 that is driven and rotated is uniformly charged by the primary charger 6, and an electrostatic latent image is formed on the photosensitive drum 5 by the image exposure. The latent image is developed with toner by the developing means 7 to form a toner image.
[0014]
To synchronize with the formation of the toner image, the recording medium S stored in the removable sheet cassette 8 or the sheet deck 9 is selectively separated and fed one by one by the feeding belt 10 and is obliquely fed by the registration roller 11. The line is conveyed to the image forming unit in accordance with the image forming timing while being corrected. Then, a toner image formed on the photosensitive drum 5 is applied to the recording medium S conveyed between the photosensitive drum 5 and the transfer charger 12 by applying a bias to the transfer charger 12 to record an image. The toner remaining on the photosensitive drum 5 after the toner image is transferred is removed by the cleaning means 13.
[0015]
The recording medium S onto which the toner image has been transferred as described above is conveyed to the fixing means 15 by the conveying belt 14, where the toner image is fixed by applying heat and pressure, and the sheet discharge tray 17 is fixed by the discharge roller 16. Is discharged.
[0016]
Note that the recording apparatus A2 according to the present embodiment has a double-sided recording function. When recording on both the front and back sides of the recording medium S, the recording medium S recorded on one side as described above is discharged as a flapper. By switching 18, the sheet is conveyed to the retransmission path 19, and reversed by switching back in the retransmission path 19. Then, the sheet is conveyed again to the image forming means by the retransmission roller 20 and recorded on the other side to be recorded on the sheet discharge tray 17. To discharge.
[0017]
[Automatic document feeder]
Next, the configuration of the automatic document feeder B that transports the document G to a reading position by the reading device A1 and discharges it to the discharge unit after reading will be described.
[0018]
FIG. 2 is an explanatory view of a main section of the automatic document feeder. The automatic document feeder B includes a document placement unit B1, a document feeding unit B2, a document transport unit B3, and a document discharge unit B4. 3 is an enlarged sectional explanatory view of the document feeding portion B2, and FIG. 4 is an enlarged sectional explanatory view of the document discharge portion B4.
[0019]
{Overall configuration of automatic document feeder}
(Original Feeding Section)
The document placing portion B1 is for placing a bundle of documents G on the stacking surface 21a of the document placing tray 21 with the document surface facing upward, and guides both sides of the set document G by abutting the side guides 21b. .
[0020]
As shown in FIGS. 2 and 3, the document feeder B2 separates a plurality of documents G set on the document placing tray 21 one by one from the uppermost document by a friction separation method, and feeds them by a pair of registration rollers. It is something to do.
[0021]
The pickup roller 22 is mounted so as to be able to swing up and down by a vertical mechanism (not shown). When feeding the original, the pickup roller 22 is lowered onto the original bundle, and the intermediate plate 23 is raised to feed the original bundle. The roller 24 is pressed to enter the preliminary feeding operation.
[0022]
Thereafter, the feeding roller 24 and the pickup roller 22 are rotated by the motor M1 as a driving source to feed the document G. At this time, the second and subsequent originals to be fed along with the uppermost sheet are stopped by the friction piece 25 and remain on the original placing tray 21. Thereafter, the document is guided by the guide member 26, passes between the feeding guide member 28 and the feeding guide member 29 constituting the feeding path 27, and is guided to the registration roller pair 30a, 30b. The registration roller pairs 30a and 30b are stopped when the leading edge of the document reaches, and after feeding the feeding roller 24 to form a loop and correcting the skew feeding, the document is fed to the document conveying section B3.
[0023]
(Original transport section)
The document conveying section B3 is configured such that the conveying belt 31 is stretched by a driving roller 32a and a driven roller 32b and is pressed against the platen glass 1 by belt pressing rollers 32c, 32d, 32e, and 32f. The conveyor belt 31 is rotationally driven when the driving roller 32a is rotationally driven by the motor M2 as a driving source. The original G fed by this rotation enters between the transport belt 31 and the platen glass 1 and is transported on the platen glass 1 by the frictional force of the transport belt 31. The document G transported to a predetermined position on the platen glass 1 by the transport belt 31 is stopped when the motor M2 is stopped, and an image is read by the reading device A1 described above.
[0024]
The document after image reading is further conveyed to the right side of FIG. 2 by re-driving the motor M2, guided by the jump table 33, and conveyed to the document discharge portion B4.
[0025]
When a small-size document is conveyed, if there is a subsequent document, the subsequent document is conveyed to a predetermined position by the rotation of the conveying belt 31 in the same manner as the preceding document, and then read by the reading device A1. During this reading operation, the preceding document is turned upside down by the document discharge section B4 and discharged onto the document discharge table 34 as will be described later.
[0026]
(Original output)
The document discharge section B4 reversely discharges the document G after reading. As shown in FIGS. 2 and 4, the reverse roller 35 has a driven roller 36 and a driven roller 37 in pressure contact with each other, and the reverse path P2. Is provided with a pair of conveying rollers 38a and 38b.
[0027]
Further, a swing flapper 39, an engagement flapper 40, a follower flapper 41, and a swing guide 42 are provided for feeding the document to the introduction path P1 or the discharge path P3 when discharging.
[0028]
The document discharge section B4 in the present embodiment has a small size document discharge mode and a large size document discharge mode according to the size of the document, and also has a double-sided reading and discharge mode when reading both sides of the document. The reversing roller 35, the flappers 39 to 41, and the swing guide 42 operate in accordance with each discharge mode.
[0029]
(Original discharge mode)
Here, the discharge state in each discharge mode will be briefly described. 5 and 6 are explanatory views of the small size original discharge mode, FIG. 7 is an explanatory view of the large size original discharge mode, and FIG. 8 is an explanatory view of the duplex scanning discharge mode.
[0030]
First, in the small size document discharge mode, as shown in FIGS. 5 and 6, the small size document G set on the document placing tray 21 (FIG. 5A) is fed by the document feeding unit B2. While feeding (FIG. 5 (b)), it is transported to a predetermined position on the platen glass 1 by the transport belt 31 and read. The original G is sent by the transport belt 31 to the introduction path P1 of the original discharge section B4, and the reverse roller 35 is driven forward (counterclockwise in FIG. 6) and sent to the reverse path P2 (FIG. 6 (a)). Further, it is fed partway through the discharge path P3 (FIG. 6 (b)). When the trailing edge of the original (downstream in the transport direction) enters the reverse path P2, the reverse roller 35 is driven to rotate backward (clockwise in FIG. 6), and the flappers 39 to 41 and the swing guide 42 are switched. Then, the original G is switched back. Then, it passes through the carry-out path P4 and is discharged from between the reversing roller 35 and the driven roller 36 to the document discharge table 34 (FIGS. 6C and 6D). At this time, the discharged document G has the document surface facing downward, and the document G continuously discharged by discharging in this way is discharged and stacked in the page order.
[0031]
Next, in the large-size document discharge mode, as shown in FIG. 7, when a large-size document read at a predetermined position on the platen glass 1 is conveyed to the document discharge section B4, it passes from the introduction path P1 through the reverse path P2. It is sent to the discharge path P3 (FIG. 7 (a)). Then, the reversing roller 35 is driven in the normal direction and the conveying belt 31 is driven in the reverse direction to convey the original G onto the platen glass 1 again (FIG. 7B). At this time, the document is in a state where the document surface is facing upward. Next, the flappers 39 to 41 and the swing guide 42 are switched, and the conveying belt 31 is driven to rotate in the forward direction, and the reverse roller 35 is driven in the reverse direction to switch back the original G and to the reverse roller 35 through the discharge path P3. And the driven roller 36 are discharged to the document discharge table 34 (FIGS. 7C and 7D). At this time, the discharged document G has the document surface facing downward, and the document G continuously discharged is discharged and stacked in the order of pages as in the case of the small size document.
[0032]
Next, in the double-sided reading / discharging mode, regardless of the small-size original and the large-size original, the original scanned on one side is transferred from the introduction path P1 to the reverse path P2, and discharged as in the case of the large-size original described above. It passes through the order of the pass P3 and is conveyed onto the platen glass 1 (states of FIGS. 7A and 7B). At this time, the original G is in a state where the other side which has not yet been read is facing downward. The original G in this state is further driven reversely by the conveying belt 31, and is conveyed to a predetermined position of the original feeding section B2, as shown in FIG. Then, the conveying belt 31 is driven to rotate forward again, the original G is conveyed to a predetermined reading position, the other side is read, and the original is read between the reversing roller 35 and the driven roller 36 through the discharge path P3 of the original discharge portion B4. Is discharged to the document discharge table 34 (the state shown in FIGS. 7C and 7D).
[0033]
The automatic document feeder B is attached so as to cover the upper surface of the platen glass 1 provided on the top of the image forming apparatus main body A, and as shown in FIG. 9 (side sectional view of the automatic document feeder). The back side (left side in FIG. 9) is pivotally attached to the image forming apparatus main body by a hinge unit 43, and the front side (right side in FIG. 9) is detachably attached to the image forming apparatus main body by, for example, a magnet catch 44. Next, the characteristic configuration of each part of the automatic document feeder B will be sequentially described.
[0034]
{Support structure of each unit}
As described above, the automatic document feeder B according to the present embodiment includes the document placement unit B1, the document feeding unit B2, the document transport unit B3, the document discharge unit B4, and the like as individual units. Then, as shown in FIG. 10, the units are combined and assembled to the image forming apparatus main body A via the hinge unit 43.
[0035]
Here, the conventional automatic document feeder is provided with a metal skeleton supported by a hinge unit on the upper part of a copying machine body, and a component for conveying a document is attached to the skeleton. It was comprised so that it might cover with the synthetic resin exterior body. For this reason, since the weight at the time of raising and lowering is increased, when the free stop mechanism is built in the hinge unit, a spring having a strength sufficient to withstand the weight is necessary, which increases the size of the hinge unit. The whole was inevitably large and heavy.
[0036]
Therefore, in the present embodiment, as shown in FIGS. 10 and 11, a support plate 45 made of sheet metal is used, and a document feeding unit B2, a document discharge unit B4, and a hinge unit as units are provided on the support plate 45. 43 is coupled by screws 46 or the like, and this support plate 45 is attached to a synthetic resin monocoque frame 47 integrated with the document placing portion B1.
[0037]
In this way, by connecting and fixing the units with the support plate 45 having high strength, the strength of the monocoque frame 47 is not required to be as high as before, so that it can be made thin, and can be reduced in size and weight. Therefore, handling and assembly are improved, and it is possible to reduce costs.
[0038]
Further, since the units are connected and fixed via the support plate 45 made of sheet metal, the ground of each unit can be easily taken from the sheet metal to the image forming apparatus main body A via the hinge unit 43. Therefore, in this embodiment, the support plate 45 is provided with a static elimination needle 48 as a static elimination member made of a conductive brush-like member so that the static elimination needle 48 comes into contact with the conveyance belt 31 when the conveyance belt 31 is assembled. It is configured. As a result, the charge removal of the conveyor belt 31 is also performed reliably.
[0039]
{Original detection configuration}
When a document is fed by the automatic document feeder B assembled as described above, it is necessary to provide a sheet sensor to detect the document position, but in this embodiment, the document passes through a plurality of paths. The number of sensors is reduced by sharing a sensor for detecting a document.
[0040]
For example, as shown in FIG. 12, the document G fed from the document placing tray 21 in the document feeding unit B2 passes through the feeding path 27 constituted by the guide members 28 and 29 as described above. A sheet sensor 49 for detecting the original G is provided, which is fed onto the platen glass 1 by the registration roller pair 30a, 30b. In the present embodiment, a photosensor comprising a light emitting element 49a and a light receiving element 49b is used as the sheet sensor 49, and the presence or absence of the original G is detected by a document passing between both elements 49a and 49b blocking the optical path of the sensor. I have to.
[0041]
The light emitting element 49a and the light receiving element 49b are attached so as to face each other with the guide members 28 and 29 constituting the feeding path 27 interposed therebetween, and each guide member 28 and 29 forms an optical path of the sensor. Slits 28a and 29a are provided. Thus, when the leading edge of the document fed from the document placing tray 21 through the feeding path 27 onto the platen glass 1 blocks the optical path of the sheet sensor 49, the sensor detects this. Then, the registration roller pair 30a, 30b starts to rotate, and the document length can be detected based on the rotation amount of the registration roller pair 30a, 30b until the trailing edge of the fed document passes through the sheet sensor 49.
[0042]
On the other hand, as described above, the document feeding unit B2 returns the document that has been read on one side in the duplex reading mode to the predetermined position of the document feeding unit B2 again by the reverse rotation of the conveying belt 31 ( (See FIG. 8). At this time, as shown in FIG. 12, the original G enters a double-sided reversing path 50 constituted by the feeding guide member 29 and the guide portion 47a of the monocoque frame 47, and the front end of the original blocks the optical path of the sheet sensor 49. Thus, the sensor 49 is detected, and a predetermined amount is conveyed from that point and stopped.
[0043]
That is, the sheet sensor 49 detects both a document fed from the document placing tray 21 onto the platen glass 1 and a document fed to the duplex reversing path 50 in the duplex reading mode.
[0044]
Note that in both cases of the document passing through the feeding path 27 and the document passing through the double-sided reversing path 50, the document detection is performed by blocking the optical path of the sheet sensor 49, but when the document passes through the feeding path 27, When the pair of registration rollers 30a and 30b and the conveyance belt 31 are driven to rotate forward and pass through the double-side reversing path 50, the conveyance belt 31 is driven to rotate reversely, so that the document is fed by detecting the drive direction of the drive motor. This is to detect whether it is in the path 27 or the double-sided inversion path 50.
[0045]
Here, in order to feed the document continuously from the document placing tray 21, when the preceding document is fed onto the platen glass 1, the leading edge of the succeeding document is moved to the registration rollers 30a and 30b. The so-called “first-out process” is performed to send in and wait. However, in the double-sided scanning mode, if there is an original in the feeding path 27, the original will block the sensor optical path and detect the original in the double-sided reversing path 50. Can not do. Therefore, in the present embodiment, in the double-sided reading mode, the advance processing is not performed, or even if the advance processing is performed, the leading edge of the succeeding document is put on standby at a position where it does not block the sensor optical path. It is configured as follows.
[0046]
The configuration for detecting a document passing through a plurality of paths by one sensor as described above is also used in the document discharge section B4 as shown in FIG. In FIG. 13, a first sensor flag 51 is rotatably provided in the middle of the introduction path P1, and the first sensor flag 51 indicates that when the document G passes through the introduction path P1, as shown in FIG. It is pushed up by the original G and rotates around the shaft 51a. Then, since the optical path of the sheet sensor 52 constituted by the photo sensor is blocked by the rotated first sensor flag 51, the document G passing through the introduction path can be detected.
[0047]
By detecting the driving amount of the motor after the leading edge of the document passes through the sheet sensor 52, not only the presence / absence detection of the document but also the conveyance amount of the document can be controlled.
[0048]
In the vicinity of the first sensor flag 51, a second sensor flag 53 is attached so as to be rotatable about a shaft 53a. One end of the second sensor flag 53 can push out the first sensor flag 51, and the other end protrudes into the conveyance area of the document conveyed by the reverse roller 35. For this reason, as shown in FIG. 15, when the original G is sent from the carry-out path P4 to the nip portion of the reverse roller 35 and the driven roller 36 by the reverse roller 35, the second sensor flag 53 is pushed around by the front end of the original. Rotate counterclockwise. Due to this rotation, the first sensor flag 51 rotates in the clockwise direction to block the optical path of the sheet sensor 52, so that the document G conveyed by the reverse roller 35 can be detected. Also in this case, similarly to the above-described document detection on the feeding side, when the document passes through the introduction path P1, the reversing roller 35 is driven forward (counterclockwise in FIG. 14), and the document is carried out by the reversing roller 35. Since the reversing roller 35 is driven in reverse rotation (clockwise in FIG. 15) when it is conveyed from the path P4 to the original discharge table 34, the original G is detected by detecting the driving direction of the motor M3 that drives the reversing roller 35. It is possible to detect which path is passing through.
[0049]
As described above, since a single sheet sensor detects a document passing through a plurality of paths, the number of sheet sensors conventionally provided for each conveyance path can be reduced, and the assembly process can be reduced. This makes it possible to reduce costs.
[0050]
{Positioning configuration of guide member during feeding}
As described above, the document fed from the document placing tray 21 onto the platen glass 1 and the document fed to the duplex reversing path 50 at the time of duplex scanning are guided by the guide member 29 during feeding. A configuration for keeping the gap between the feeding guide member 29 and the conveying belt 31 constant will be described. 16A is a schematic cross-sectional explanatory view of the guide member 29 and the conveying belt 31 during feeding when viewed from a direction orthogonal to the document conveying direction, and FIG. 16B is a drawing in which both ends are rotatably attached. FIG. 6 is a schematic cross-sectional explanatory view of the guide member 29 ′ and the conveyance belt 31 as viewed from the document conveyance direction.
[0051]
As shown in FIG. 16 (a), a gap d is formed between the leading end of the guide member 29 being fed and the conveyance belt 31 to feed the original G from the feed path 27. When this gap becomes large, when the document is fed into the duplex reversing path 50 during duplex scanning, the document returned by the conveyance belt 31 enters the feeding path 27 without being guided to the duplex reversing path 50. For this purpose, a mylar sheet 54 is attached to the tip of the guide member 29 being fed, and the gap between the tip of the mylar sheet 54 and the conveying belt 31 is set to be as small as about 0.5 mm.
[0052]
In order to keep the gap constant, conventionally, both ends of the guide member during feeding (both ends in the direction perpendicular to the document conveying direction) are rotatably attached by the shaft member, and both ends of the guide member on the rotation side are conveyed. The positioning is performed by abutting against a belt frame as a support member for supporting the belt.
[0053]
However, as shown in FIG. 16 (b), the conveyance belt 31 can swing up and down within a certain range on one side in the rotation axis direction so that even a small-size document can be securely attached. It is composed. Therefore, when one side of the conveyor belt 31 swings and tilts with respect to the platen glass 1, the leading end of the feeding guide member 29 ′ that is abutted against the belt frame 55 is positioned on the belt frame 55 on one side. Although it is abutted, it is lifted from the belt frame 55 on the other side. For this reason, the gap d ′ between the conveyance belt 31 and the feeding guide member 29 ′ becomes large in that portion, and the document returned by the conveyance belt 31 easily enters the feeding path 27. In order to reduce the size of the apparatus, the diameter of the driving roller 32a that stretches the conveying belt 31 is reduced, the height of the platen glass surface and the tip of the guide member during feeding is reduced, and the tip is curled upward. This is more likely to occur when a document is conveyed.
[0054]
Therefore, in this embodiment, as shown in FIG. 17, the feeding guide member 29 is configured to follow the swinging of the conveyor belt 31. 17A is a schematic explanatory view showing the front side of the conveying belt 31 and the guide member 29 being fed, and FIG. 17B is a schematic explanatory view of the back side of the apparatus. The transport belt 31 has a rotation shaft on the front side of the apparatus fixed in the vertical direction, but the rotation shaft on the back side of the apparatus is configured to be swingable in the vertical direction.
[0055]
As shown in FIGS. 17 (a) and 17 (b), both ends of the guide member 29 during feeding are rotatably attached by a shaft 56, and a tension spring 57 is attached to the turning tip side, and the turning tip is attached. Both sides are configured to abut against the belt frame 55 of the conveyor belt 31 and be positioned. Further, the back side of the guide member 29 during feeding is attached to the shaft 56 so as to be rotatable by a long hole 29b.
[0056]
As described above, since one side of the feeding guide member 29 (the swing side of the transport belt 31) is configured to be rotatable by the long hole 29b, when the transport belt 31 swings in the vertical direction, the feed is in progress. The guide member 29 can swing up and down accordingly, and the guide member 29 maintains the state in which the front side and the back side of the apparatus are in contact with the belt frame 55 with respect to the conveyor belt 31. become. For this reason, the gap between the conveyance belt 31 and the leading end of the guide member during feeding is always kept constant, and a document sent to the duplex reversing path 50 in the duplex reading mode does not enter the feeding path 27 by mistake. Is.
[0057]
{Oscillating flapper}
As shown in FIG. 4, the document discharge unit B4 described above inverts the document G from which the image on one side is read and discharges it onto the document discharge table 34, or reverses the document G from which the image on one side is read. Then, the sheet G is sent again onto the platen glass 1, or the document G from which both-side images are read is discharged onto the document discharge table 34. Since the document conveying section B4 operates as described above, the swingable flapper 39 for switching the sheet path for guiding the document G, and the follow-up flapper 41 that swings following the swing flapper 39. A discharge driving mechanism 58 for driving each part such as an engaging flapper 40 that swings in conjunction with the swinging of the swinging flapper 39 by engaging with the swinging flapper 39, and a roller that constitutes the document conveying section B4. (See FIG. 26). Hereinafter, the outline of each part constituting the document conveying part B4 will be sequentially described in detail.
[0058]
First, the swingable flapper 39 for switching the sheet path for guiding the document will be described in detail.
[0059]
As shown in FIG. 4, the swing flapper 39 guides the original G from which the image on one side is read to the reversal path P2 via the introduction path P1 in order to invert the original G from which the image on one side is read. Switch to guide to discharge path P3 to feed again onto platen glass 1 via reversing path P2 or to guide to discharge path P3 to discharge document G from which images on both sides are read onto document discharge table 34 It is done.
[0060]
As shown in FIGS. 19, 20, and 21, the swing flapper 39 is divided into two flappers and arranged on the same axis. In this divided swing flapper 39, one divided first swing flapper 59 is fixed to the shaft 61, and the other second swing flapper 60 is rotatably attached to the shaft 61. When the first swing flapper 59 is rotated, the other second swing flapper 60 is rotated via an elastic member 62 such as a coil spring.
[0061]
More specifically, when the first swing flapper 59 rotates in the clockwise direction in FIG. 19, the abutment portion 59 a of the first swing flapper 59 becomes the abutment portion of the second swing flapper 60. The second swing flapper 60 pivots in the same direction (clockwise direction) as the first swing flapper 59 and swings to a position as shown in FIG. . The swing flapper 39 swings to a position as shown in FIG. 19 and stops. This is provided in the drive transmission path of the discharge drive mechanism 58 (see FIGS. 24 and 25), which will be described in detail later. This is done by turning off the torque limiter.
[0062]
On the other hand, when the first swing flapper 59 is rotated counterclockwise in FIG. 20, the abutting portion 59b of the first swing flapper 59 is second swung via an elastic member 62 such as a coil spring. The abutting portion 60b of the flapper 60 is elastically pressed, and the second swing flapper 60 rotates in the same direction as the rotation direction of the first swing flapper 59.
[0063]
At this time, if the leading edge of the document does not intervene in the swing area of the swing flapper 39, the second swing flapper 60 swings to the position where it enters the outer conveyance guide 63 as shown in FIG. When the leading edge of the document is interposed in the swing region of the swing flapper 39, the second swing flapper 60 has the elastic force of the elastic member 62 interposed between the abutting portions 59b and 60b. 21 stops at the position escaped from the conveying outer guide 63 by the thickness of the document as shown in FIG. 21, and does not swing to the position shown in FIG.
[0064]
In this embodiment, when the leading edge of the document is interposed between the swing flapper 39 and the conveyance outer guide 63, the first swing flapper 59 rotates 23 ° counterclockwise. When the two swing flapper 60 is rotated 10 ° counterclockwise, the leading edge of the original G is sandwiched between the outer guide 63 and stopped, and the first swing flapper 59 rotates the remaining 13 °. Is absorbed by the elastic member 62 interposed between the abutting portions 59b and 60b.
[0065]
As described above, the swingable swing flapper 39 for switching the sheet path is configured to swing to the position where it enters the outer guide 63 when rotating counterclockwise as shown in FIG. ing. However, for example, as shown in FIG. 18, when the swing flapper 39 ′ is an integrally molded product, in order to increase productivity, when the space between the previous transported document and the next transported document is narrowed, the following Such a problem may occur.
[0066]
That is, the leading edge of the next transported document stands by between the swing flapper 39 'and the transport outer guide 63 while the previous transported document is transported in the reverse path P2. However, here, when the swing flapper 39 ′, which is the integrally molded product, is rotated counterclockwise in order to discharge and transport the previous transported document, the swing flapper 39 ′, which is the integrally molded product, causes the Stress is applied to the leading edge of the next transport document, and in the worst case, it may be folded or torn.
[0067]
In order to prevent this, in this embodiment, as described above, the swing flapper 39 is divided into two flappers and arranged on the same shaft, and one first swing flapper 59 is fixed to the shaft 61. The other second swing flapper 60 is rotatably attached to the shaft 61 so that the other second swing flapper 60 is rotated by the rotation of the first swing flapper 59. It is composed.
[0068]
Further, when the first swing flapper 59 is rotated in the counterclockwise direction in FIG. 20 to rotate the second swing flapper 60 in the same direction, the swing flapper 39 swings. In the case where the leading edge of the document is present in the area, the second swing flapper 60 is lost against the waist of the document interposed in the area by the action of the elastic member 62 interposed between the abutting portions 59b and 60b. It stops at the position shown in FIG. 21 and does not swing to the position shown in FIG.
[0069]
With this configuration, it is possible to reduce the stress applied to the leading edge of the original G when the swing flapper 39 is switched while improving productivity, and to prevent problems such as damage to the original.
[0070]
{Follow-up flapper}
Next, the follow-up flapper 41 that swings following the swing of the swing flapper 39 will be described in detail.
[0071]
The swing flapper 39 is configured to be swingable from a position shown in FIG. 19 to a position shown in FIG. However, for example, by switching the swing flapper 39 ′ from the position shown in FIG. 18 (a) to the position shown in FIG. 18 (b), the discharge formed by the swing flapper 39 ′ and the in-conveyance guide 64. When the interval L (gap) of the path P3 becomes too wide, the document G entering the discharge path P3 increases in the degree of freedom at the leading end and enters at a steep angle. As a result, the leading edge of the document G may be buckled, or it may continue to be conveyed with the leading edge caught and jammed.
[0072]
Therefore, as described above, the follow-up flapper 41 that swings following the swing of the swing flapper 39 is provided. As shown in FIGS. 19 and 20, the follow-up flapper 41 is swingably attached to protrusions 65 provided at both ends in the width direction of the inner guide 64 (direction intersecting the transport direction).
[0073]
19, the abutting portion 68 integral with the follow-up flapper 41 is elastically pressed by the elastic abutting portion 67 attached to the arm member 66 integral with the first swing flapper 59 as shown in FIG. Thus, the configuration shown in FIG. 19 is maintained. The arm member 66 integral with the first swing flapper 59 and the abutting portion 68 integral with the follow-up flapper 41 are disposed at the end in the axial direction outside the document G conveyance area. Further, the elastic abutting portion 67 attached to the arm member 66 integral with the first swing flapper 59 is configured to be elastically movable in the arrow direction in FIG.
[0074]
When the first swing flapper 59 rotates counterclockwise from the state shown in FIG. 19, the pressing of the arm member 66 against the follow-up flapper 41 by the elastic abutting portion 67 is released. At the same time, the follow-up flapper 41 starts to swing clockwise around the projection 65 by its own weight, and finally the stopper 69 (in this embodiment, the projection provided on a part of the side plate constituting the frame of the document conveying portion B4). ) The sheet path stops, and forms a sheet path having a predetermined gap (gap) as shown in FIG.
[0075]
With this configuration, an interval between the sheet path P31 formed between the swing flapper 39 and the in-conveyance guide 64 when the swing flapper 39 swings to a position as shown in FIG. Since the degree of freedom of the leading edge of the original G that is held at the interval of the sheet path P32 and enters from the direction of the arrow in the figure is restricted, buckling or jamming of the conveyed original can be prevented.
[0076]
The introduction path P1 (outside the conveyance guide 63 side) is provided with a sensor flag 70b that constitutes a sheet sensor 70 that detects a document passing through the sheet path P32 of the introduction path P1 and the discharge path P3. However, when the swing flapper 39 'swings to the position shown in FIG. 18 (b), the interval of the discharge path P3 formed between the swing flapper 39' and the transport guide 64 is too wide. Then, there is a concern that the document passing through the discharge path P3 may pass through a position where the sensor flag 70b does not reach.
[0077]
Even in such a case, in the present invention, as described above, the follow-up flapper 41 that regulates the path interval of the discharge path P3 to a predetermined interval is provided so as to follow the swing flapper 39 and swing. The sheet sensor 70 including the sensor flag 70b and the photosensor 70a can reliably detect the document passing through the sheet path P32 of the discharge path P3 without providing a separate sheet sensor for detecting the document passing through the discharge path P3. can do.
[0078]
{Engagement flapper}
Next, the engagement flapper 40 that engages with the swing flapper 39 and swings in conjunction with the swing of the swing flapper 39 will be described in detail.
[0079]
The automatic document feeder B has an engagement flapper 40 as shown in FIGS. 22 and 23 in addition to the swing flapper 39 and the follow-up flapper 41 described above. However, in an apparatus having a plurality of swingable flappers for switching sheet paths in this way, it is costly to configure each flapper to be individually switched and driven by a driving means such as a solenoid or a motor. There is a problem that the device configuration and the control sequence become complicated.
[0080]
Therefore, the engaging flapper 40 is arranged and configured to be engageable with a swinging flapper 39 swung by a discharge drive mechanism 58 (see FIGS. 24 to 26) described later. The engagement flapper 40 is configured to swing in conjunction with it. That is, a plurality of flappers are swung by one driving means.
[0081]
Normally, the engagement flapper 40 is urged in the direction of the reverse roller by the urging force of the urging member 71 such as a spring, but the abutting portion 72 of the engagement flapper 40 constitutes the frame of the document conveying portion B4. 22 is abutted against a stopper 73 provided on the side plate to be held at the first position as shown in FIG. In this state, as shown in FIG. 22, the engaging portion 74 provided on the engaging flapper 40 and the engaging portion provided on the swing flapper 39 (the arm member 66 integral with the first swing flapper 59). 75 is in a separated state.
[0082]
When the swing flapper 39 rotates counterclockwise about the shaft 61 from the state shown in FIG. 22, the engaging portion 75 of the swing flapper 39 is moved to the engagement flapper 40 as shown in FIG. The engagement flapper 40 is pushed clockwise against the urging force of the urging member 71 and the engagement flapper 40 rotates clockwise about the shaft 76 according to the rotation of the swing flapper 39. It is rotated in the direction and held at the second position as shown in FIG.
[0083]
When the engagement between the engagement portion 75 of the swing flapper 39 and the engagement portion 74 of the engagement flapper 40 is released, the engagement flapper 40 is rotated by the urging force of the urging member 71. However, it is held against the original position as shown in FIG.
[0084]
With this configuration, the engagement flapper 40 can also be switched and driven by a drive mechanism 58 (described later) that switches and drives the swing flapper 39, that is, a plurality of flappers can be switched and driven by one driving means. It is not necessary to provide driving means such as a solenoid or a motor, and the cost can be reduced. Furthermore, the apparatus configuration and control sequence can be simplified. Further, various sheet paths can be formed in a narrow space.
[0085]
{Discharge drive mechanism}
Next, the discharge driving mechanism 58 that drives each part of the document conveying section B4 will be described in detail.
[0086]
As described above, in an apparatus having a plurality of swingable flappers for switching sheet paths, it is costly to configure each flapper to be individually switched and driven by a driving means such as a solenoid or a motor. There is a problem that the device configuration and the control sequence are complicated.
[0087]
Accordingly, as shown in FIG. 26, the discharge driving mechanism 58 in the automatic document feeder B operates each part of the document transport section B4 with one drive means via drive transmission means constituted by gears and the like. It is composed. In the present embodiment, a motor M3 capable of forward / reverse driving is used as the driving means.
[0088]
As shown in FIG. 26, the motor M3 is attached to one side plate 78 in the width direction constituting the frame 77 of the document conveying section B4. The power of the motor M3 is transmitted from the motor pulley 79 to the transmission pulley 81 via the timing belt 80, and the reverse is provided on one end side of the reverse roller shaft 83 meshing with the transmission gear 82 integral with the transmission pulley 81. It is transmitted to the gear 84. As a result, the reversing roller 35 and the driven roller 36 that rotates following the reversing roller 35 are driven to rotate forward and backward.
[0089]
Further, as shown in FIGS. 26 and 24, the power of the motor M3 is transmitted to the reverse gear 85 on the other end side via the reverse roller shaft 83 and is engaged with the reverse gear 85. Is transmitted to the outer gear 87a of the step gear 87 provided with The power transmitted to the outer gear 87a of the step gear 87 having the torque limiter 86 is transmitted to the sector gear 88a meshing with the inner gear 87b of the step gear 87, and the arm member 88 having the sector gear 88a Swing.
[0090]
As a result, as shown in FIG. 25, the projection 88b provided at the free end of the arm member 88 has a slot-like groove 89a provided in the arm member 89 fixed to the shaft 61 of the swing flapper 39 and the document conveyance. The swing flapper 39 swings while being controlled by the arc hole 91 provided in the other side plate 90 in the width direction constituting the frame 77 of the part B4. Then, when the projection 88b comes into contact with one end 91a of the arc hole 91 and stops, the torque limiter 86 of the step gear 87 is cut, and the swing flapper 39 is in one position (position shown in FIG. 19). When the projection 88b stops and stops against the other end 91b of the arc hole 91, the torque limiter 86 of the step gear 87 is similarly cut off and the swing flapper 39 is moved to the other position (FIG. 20 or FIG. 20). Stop at position 21).
[0091]
By configuring as described above, it is not necessary to provide driving means such as a solenoid and a motor for each flapper, so that the cost can be reduced, the device configuration and the control sequence can be simplified, and further, the solenoid and the like can be simplified. This eliminates the need for electrical parts and these harness processing.
[0092]
The power transmitted to the step gear 87 including the torque limiter 86 is also transmitted to another sector gear 92a meshing with the inner gear 87b of the step gear 87, and the lever 92 including the sector gear 92a Swing. Then, a torsion coil spring 93 engaged with the free end of the lever 92 and a swing guide 42 fixed to a shaft 95 to which these are attached via a V-shaped arm 94 engaged with the torsion coil spring 93 are swung. Move. As with the swing flapper 39, the swing guide 42 is configured to swing to a predetermined position and stop when the torque limiter 86 of the step gear 87 is cut.
[0093]
Further, the arc hole 91 provided in the side plate 90 that regulates the swing region of the projection 88b of the arm member 88, that is, the swing region of the swing flapper 39, adjusts the restriction range that is the range of the hole to an arbitrary range. It is configured to be possible. In this embodiment, as shown in FIG. 25, an adjustment plate 96 is slidably attached to the other side plate 90 in the width direction constituting the frame 77 of the document conveying section B4, and the adjustment plate 96 is moved up and down in the direction of the arrow in the figure. By moving, the position of one end 91a of the arc hole 91 is changed by the abutting part 96a of the adjusting plate 96, and the arc hole 91 for regulating the projection 88b of the arm member 88 is changed. The restriction range is adjusted to an arbitrary range.
[0094]
With this configuration, the gap between the tip of the swing flapper 39 and the conveyor belt 14 can be easily adjusted to a predetermined gap. The gap between the tip of the swing flapper 39 and the conveyor belt 14 is difficult to guarantee a predetermined gap due to variations in the circumferential length of the conveyor belt 14 and the accuracy of parts of the swing flapper 39. If there is, there is a risk that a document will be caught between the tip of the swing flapper 39 and the conveyor belt 14. For this reason, by adopting the adjustment type as described above, the gap between the tip of the swing flapper 39 and the conveyor belt 14 can be guaranteed to be a predetermined gap, thereby improving the transportability.
[0095]
In the control sequence during the small size document discharge mode of the apparatus, the document G conveyed in the forward direction when the motor M3 is driven forward is reversed by the swing flapper 39 and the engagement flapper 40 via the introduction path P1. After being guided to the path P2 (see FIG. 6), when the motor M3 is driven in reverse to transport the original G in the reverse direction and the engagement flapper 40 is switched and guided to the unloading path P4, the engagement flapper The document G is transported in the forward direction by the amount necessary to switch 40.
[0096]
In this embodiment, as shown in FIGS. 13 to 15, a predetermined time (switching the engagement flapper 40) is detected after the trailing edge of the document is detected by the sheet sensor 52 (also serving as a registration sensor) disposed in the vicinity of the engagement flapper. When the motor M3 is driven to rotate in the reverse direction and the swing flapper 39 and the engagement flapper 40 are switched to the positions shown in FIG. It is configured to transport in the reverse direction.
[0097]
The sheet sensor 52 not only detects the trailing edge of the document G when the document G is conveyed in reverse as described above, but also the leading edge of the document G when performing registration adjustment (skew correction) of the document G. It also serves as a detection. That is, when the document G is fed to the reversing path P2 via the introduction path P1, the sheet sensor 52 detects the leading edge of the document, and then the nip portion between the reversing roller 35 and the driven roller 37 that has stopped rotating. After correcting the skew feeding by abutting the leading edge of the document, the reversing roller 35 is driven to rotate to convey the document G. The sheet sensor 52 detects the edge of the document at this time. It is configured to do.
[0098]
By configuring as described above, it is possible to prevent a problem caused by the inverted original G reaching the engaging flapper portion before the engaging flapper 40 is switched. Further, since the sheet sensor 52 that detects the trailing edge of the document uses a sheet sensor that also serves to detect the leading edge of the document when the registration of the document G is adjusted, the cost can be reduced and the apparatus configuration can be reduced. And the control sequence can be simplified.
[0099]
[Other Embodiments]
In the above-described embodiment, the copying machine is exemplified as the image forming apparatus. However, the present invention is not limited to this. For example, the image forming apparatus may be another image forming apparatus such as a scanner, a printer, or a facsimile machine. The same effect can be obtained by applying the present invention to a sheet material feeding device used in an image forming apparatus.
[0100]
In the above-described embodiment, the sheet material feeding device that feeds a sheet material such as recording paper as a recording target to the recording unit is illustrated, but the present invention is not limited to this, and for example, a reading target The same effect can be obtained even if the present invention is applied to a sheet material feeding apparatus for feeding a sheet material such as a document to the reading means.
[0101]
In the above-described embodiment, the electrophotographic method is exemplified as the recording method. However, the recording method is not limited to this, and other recording methods such as an ink jet method may be used.
[0102]
【The invention's effect】
Since the present invention is configured as described above, it is not necessary to provide a sensor for each path by sharing a sensor for detecting a document passing through each path. For this reason, the number of sensors can be reduced, the number of parts can be reduced, and the cost can be reduced.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of an internal configuration of a copying machine as an example of an image forming apparatus equipped with an automatic document feeder.
FIG. 2 is a main cross-sectional explanatory view of an automatic document feeder.
FIG. 3 is an enlarged cross-sectional explanatory diagram of a document feeding unit.
FIG. 4 is an enlarged cross-sectional explanatory view of a document discharge portion.
FIG. 5 is an explanatory diagram of a small size document discharge mode.
FIG. 6 is an explanatory diagram of a small size document discharge mode.
FIG. 7 is an explanatory diagram of a large size document discharge mode.
FIG. 8 is an explanatory diagram of a duplex reading / discharging mode.
FIG. 9 is an explanatory side sectional view of the automatic document feeder.
FIG. 10 is an exploded perspective view of each unit such as a document feeding unit and a document discharging unit.
FIG. 11 is an explanatory diagram illustrating a state in which units such as a document feeding unit and a document discharge unit are connected and fixed by a support plate.
FIG. 12 is a diagram illustrating a configuration in which a document that passes a plurality of passes is detected by a single sheet sensor in a document feeding unit.
FIG. 13 is an explanatory diagram of a configuration in which a document passing through a plurality of passes is detected by one sheet sensor in a document discharge unit.
FIG. 14 is an explanatory diagram of a configuration in which a document passing through a plurality of paths is detected by one sheet sensor in a document discharge unit.
FIG. 15 is an explanatory diagram of a configuration in which a document passing through a plurality of passes is detected by one sheet sensor in a document discharge unit.
FIG. 16A is a schematic cross-sectional explanatory view of the feeding guide member and the conveying belt as viewed from a direction orthogonal to the document conveying direction, and FIG. 16B is a feeding guide member in which both ends are rotatably attached. FIG. 6 is a schematic cross-sectional explanatory view of the transport belt as viewed from the document transport direction.
FIG. 17A is a schematic explanatory view showing the front side of the apparatus between the conveying belt and the guide member being fed, and FIG. 17B is a schematic explanatory view of the back side of the apparatus.
FIG. 18 is a schematic cross-sectional view showing a switching state of a swing flapper that is an integrally molded product.
FIG. 19 is a cross-sectional view of a main part showing a switching state of divided swing flappers.
FIG. 20 is a cross-sectional view of a main part showing a switching state of divided swing flappers.
FIG. 21 is a cross-sectional view of a main part showing a switching state of divided swing flappers.
FIG. 22 is a schematic cross-sectional view showing a switching state between a swing flapper and an engagement flapper.
FIG. 23 is a schematic cross-sectional view showing a switching state between a swing flapper and an engagement flapper.
FIG. 24 is an explanatory diagram showing a part of a drive transmission path of the discharge drive mechanism.
FIG. 25 is an explanatory diagram showing a part of a drive transmission path of the discharge drive mechanism.
FIG. 26 is an explanatory diagram showing a drive transmission path of the discharge drive mechanism.
[Explanation of symbols]
A: Image forming apparatus main body
A1 ... Reader
A2 ... Recording device
B: Automatic document feeder
B1: Document placement section
B2 ... Document feeder
B3 ... Document feeder
B4 ... Document output section
G: Manuscript
L ... Interval
M1, M2, M3 ... Motor
P1 ... Introduction path
P2 ... Reverse path
P3… discharge path
P31 ... sheet path
P32 ... sheet path
P4 ... Unloading path
S: Recording medium
1 ... Platen glass
2 Light source
3 ... mirror
4 ... Lens
5 ... Photoconductor drum
6 ... Primary charger
7: Developing means
8 ... Sheet cassette
9 ... Seat deck
10 ... Feed belt
11… Registration roller
12 ... Transfer charger
13 Cleaning means
14… Conveyor belt
15: Fixing means
16… discharge roller
17… Sheet discharge tray
18… Discharge flapper
19 ... Retransmission path
20… Resending roller
21 ... Document tray
21a ... Loading surface
21b ... Side guide
22… Pickup roller
23… Middle plate
24… feed roller
25… friction piece
26… Guide material
27… Feeding pass
28… Feeding guide member
28a, 29a ... slit
29… Guide material during feeding
29b ... long hole
30a, 30b ... Registration roller pair
31… Conveyor belt
32a ... Driving roller
32b ... driven roller
32c, 32d, 32e, 32f ... Belt pressing roller
33… Jump stand
34 ... Document output tray
35… Reverse roller
36… driven roller
37… Followed roller
38a, 38b ... Conveying roller pair
39… Oscillating flapper
39 '… Oscillating flapper
40 ... Engagement flapper
41… Follow-up flapper
42… Oscillating guide
43… Hinge unit
44… Magnet catch
45… Support plate
46… Screw
47… Monocoque frame
47a ... guide section
48 ... Static elimination needle
49… Seat sensor
49a ... Light emitting element
49b ... Light receiving element
50 ... Both sides inversion path
51 ... 1st sensor flag
51a ... axis
52… Seat sensor
53… Second sensor flag
53a ... axis
54 Mylar seat
55… belt frame
56… axis
57… Tension spring
58… discharge drive mechanism
59 ... 1st swing flapper
59a ... the abutment section
59b ... the abutment
60 ... 2nd swing flapper
60a ... the abutment part
60b ... Abutting part
61… axis
62… Elastic member
63… Outside transfer guide
64… Guide in transport
65… projection
66… Arm member
67… Elastic bump
68… Abutment
69… Stopper
70… Seat sensor
70a Photosensor
70b Sensor flag
71… Biasing member
72… Abutting part
73… Stopper
74… engaging part
75… engaging part
76… axis
77… Frame
78… Side plate
79… motor pulley
80… Timing belt
81… Transmission pulley
82… Transmission gear
83… Reverse roller shaft
84… Reversing gear
85… Reversing gear
86… Torque limiter
87… stage gear
87a… Outer gear
87b ... Inner gear
88… Arm member
88a ... Sector gear
88b ... Protrusions
89… Arm members
89a ... slotted groove
90… Side plate
91… Arc hole
91a ... end
91b ... end
92… Lever
92a Sector gear
93… Torsion coil spring
94… V-shaped arm
95… axis
96… Adjustment plate
96a ... the abutment part

Claims (5)

In an automatic document feeder that transports and discharges a set document to a predetermined position,
Multiple document paths for transporting documents,
A detection sensor for detecting the conveyed document,
A single detection sensor configured to detect the presence or absence of a document passing through a plurality of document paths;
The plurality of document paths are provided in a document feeding unit, a feeding path for transporting a document from the document feeding unit to the document transport unit, and a duplex reversing path for transporting the document when reading both sides of the document. ,
The detection sensor is constituted by an optical sensor, and an optical path of the optical sensor is provided in a guide member that partitions the feeding path and the double-sided reversing path,
An automatic document feeder, wherein when a plurality of documents are continuously fed in the double-sided reading mode, the subsequent documents wait in a position where they do not block the sensor optical path . In an automatic document feeder that transports and discharges a set document to a predetermined position,
Multiple document paths for transporting documents,
A detection sensor for detecting the conveyed document,
A single detection sensor configured to detect the presence or absence of a document passing through a plurality of document paths;
The automatic document feeder according to claim 1, wherein the plurality of document paths are provided in a document discharge unit, and are an introduction path for introducing a document and a carry-out path for discharging the document. 3. The automatic document feeder according to claim 1, wherein the document detection by the sensor determines which document path is in the document path according to a driving direction of a driving source for conveying the document . In an automatic document feeder that transports and discharges a set document to a predetermined position,
Multiple document paths for transporting documents,
A detection sensor for detecting the conveyed document,
A single detection sensor configured to detect the presence or absence of a document passing through a plurality of document paths;
The automatic document feeder according to claim 1, wherein the document detection by the sensor determines whether a document is in a document path according to a driving direction of a driving source for transporting the document. In an image forming apparatus that forms an image by reading a document,
An automatic document feeder according to any one of claims 1 to 4,
A reading device for reading a document conveyed by the automatic document conveying device;
A recording apparatus for forming an image on a recording medium in accordance with the read information;
An image forming apparatus.

Images