JPH115673A - Automatic document feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the size of the feeder with a simplified path structure and feed mechanism by providing a reversing part between a document read part and a paper discharge part, and arranging a pinch roller for press-transporting a document with a transport roller near the outlet of the reversing part, whereby the document is reversed in the reversing part to be sent back to the read part or the paper discharge part. SOLUTION: An inlet end and an outlet end of an introduction guide 27 are provided with pinch rollers 30, 31 respectively to assist transport in a paper discharge path 32 and feeding and discharging to a document reversing part 10, especially the pinch roller 31 has a function of reversing registration in reading the back of a document G. That is, the pinch roller 31 is pressed to a transport roller 22 to be rotated jointly, but in registration, the rotation of the transport roller 22 is stopped to impinge the leading end of the document to the press-contacting position 50 of both rollers to register the document. Accordingly, the leading end of the document G is not brought into sliding contact with the peripheral surface of the transport roller 22. While the reversing part 10 and the paper discharge part 9 are connected to each other by a path with a small radius of curvature, the document can be discharged smoothly without lowering of transport force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic document feeder used for an image reading apparatus such as a copying machine or a facsimile.

[0002]

2. Description of the Related Art Conventionally, for example, an automatic document feeder installed on a copying machine main body automatically sends out documents placed on a paper feed tray one by one to a reading means on the copying machine main body. And read it by the optical system inside the copier body,
A configuration in which a document is conveyed to a paper discharge unit is generally employed (a similar technique is disclosed in Japanese Patent Laid-Open No. 8-133551).

Meanwhile, there has been proposed a conventional automatic document feeder capable of reading images on both sides of a document. In this method, a document sent out from a paper feed tray is wound by a large transport roller and transported to a document reading section facing reading means of the copying machine body, and the document reading section reads the document. After reading the surface of the original by means,
The original is inverted using a switchback path provided on the downstream side thereof, and the reverse side of the original is read by transporting the original again on the peripheral surface of the transport roller. This is a configuration in which the paper is aligned and then discharged onto a paper discharge tray.

[0004]

However, in the above-described conventional automatic document feeder, since both the switchback path and the reverse discharge path are provided, the path structure and the feed mechanism are complicated, and the automatic document feeder is provided. There was a problem that the device itself became larger. On the other hand, if both paths are to be shared, the radius of curvature of the path must be reduced, and there is a possibility that a sufficient document conveying force cannot be obtained.

Further, when the document is fed from the switchback path to the transport path, the leading edge of the document is registered by using a transport roller. Since the distance of sliding contact with the peripheral surface of the transport roller is long, there is a possibility that the document may not be properly transported due to friction with the peripheral surface of the transport roller.

Accordingly, the present invention achieves downsizing of the automatic document feeder itself by simplifying the path structure and the feed mechanism.

Further, the present invention enables a sufficient document conveying force to be obtained even if the radius of curvature of the document discharge path is reduced.

Further, it is possible to reliably register a reversal document conveyed from a switchback path without being adversely affected by peripheral friction of a conveyance roller.

[0009]

According to an aspect of the present invention, there is provided an automatic document feeder, comprising: a document feeding unit, a document reading unit, a document discharging unit, And a transport roller for transporting the original along the transport path. The originals stacked on the original feeder are sequentially fed to the original reader to read the original surface. Then, in an automatic document feeder that discharges a document to the document discharge section, a document reversing section is provided between the document reading section and the document discharging section, and the vicinity of an exit of the document reversing section is provided. A pinch roller that presses and conveys a document between the conveyance roller and the document reversing section, in which the front and rear ends of the document are reversed and sent out again to the document reading section or the document discharge section. It is characterized by.

According to a second aspect of the present invention, in the automatic document feeder, the pinch roller pushes a leading end of the document sent from the document reversing section to the document reading section to a pressure contact position with the transport roller. After the contact and alignment, the original is pressed and conveyed between the conveying rollers.

According to a third aspect of the present invention, in the automatic document feeder according to the present invention, the leading end of the document sent from the document reversing section is pressed against the conveyance roller and the pinch roller near the upstream side of the pinch roller. A guide means for guiding to the position is provided.

According to a fourth aspect of the present invention, in the automatic document feeder according to the present invention, the document sent out by the pinch roller is provided near the downstream side of the pinch roller on the document reading unit side or the document discharge unit side. It is characterized in that switching means for leading to either one is provided.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an automatic document feeder according to the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is an overall schematic view of an automatic document feeder according to this embodiment, and FIG. 2 is an enlarged view of a main part.

The automatic document feeder 1 according to this embodiment has
A paper feed tray 2 on which a document is placed, a document take-out means 4 provided in the vicinity of a paper feed port 3, and a paper feed from the paper feed port 3 to a document reading section facing the document reading means 5 of the copying machine main body H. Paper path 6
A registration roller 7 provided in the middle of the paper feed path 6 for aligning the leading edge of the original; a conveying unit 8 for conveying the aligned original to the original reading unit; A document discharge unit 9 for discharging a document, and a document reading unit 5
And a document reversing unit 10 provided between the document discharging unit 9 and the document reversing unit 10. The document placed on the paper feed tray 2 is sequentially fed to the document reading unit, and the surface of the document is read. The document is discharged to the document discharge unit 9 or is switched back by the document reversing unit 10 after reading the document, and is again fed to the document reading unit by the transport unit 8 to read the back side.

The copying machine main body H includes a transparent glass 11 for reading an image by the document reading section 5 when the document is automatically fed;
A platen 12 for reading when an original such as a book is placed.

The paper feed tray 2 is disposed so as to be inclined toward the paper feed port 3 of the apparatus main body, and is provided with a guide plate 13 movable in the width direction of the original. The width of the original is
3 is detected. Further, the paper feed tray 2 is provided with two size detection sensors S1 for detecting the document length in the feeding direction in the feeding direction. This size detection sensor S1 is composed of, for example, a limit switch, an optical sensor, and the like. In the case of the normal mode in which the documents placed on the paper feed tray 2 are all the same size, the size of the document is detected using the guide plate 13 and the size detection sensor S1.

The document take-out means 4 is provided near the paper feed port 3 and is capable of displacing a document placed on the paper feed tray 2 in the thickness direction. An arm 15 rotatably supports the roller 14, and a separation roller 16 located at the other end of the arm 15. The paper feed roller 14 is normally in the standby position, and is moved from the machine position to the paper feed position by the operation of the paper feed clutch 17a.
The document feeder 2 rotates following the rotation of, and feeds out the document on the paper feed tray 2. The separation roller 31 is rotated by the paper supply clutch 17b that operates simultaneously with the reverse rotation of the paper supply inversion motor 18, and separates the original one by one from the separation pad and sends out the original to the feeding path 6.

A registration sensor S2 for detecting the leading edge of the document is disposed near the downstream side of the separation roller 16, and a registration roller 7 is further disposed near the downstream side. The registration roller 7 includes a driving roller 20 and a driven roller 21, and the driving roller 20 rotates at a predetermined timing by the normal rotation of the sheet reversing motor 18. When the leading edge of the document comes into contact with the registration roller 7 and the leading edge is aligned, the drive roller 20 rotates after waiting for a certain time, and the driven roller 2
1 and is conveyed to the paper feed path 6 with the original sandwiched therebetween.

The conveying means 8 includes a conveying roller 22 for winding and conveying the original, and pinch rollers 23 and 24 arranged on the peripheral surface of the conveying roller 22. Then, the document is gripped between the transport roller 22 and the pinch rollers 23 and 24 and sent to a document reading unit facing the document reading unit 5. The rotation direction of the transport roller 22 is switched by forward and reverse rotations of the pulse motor 25.

A read sensor S3 is provided upstream of the original reading section.
Is arranged. The read sensor S3 is used for detecting the leading edge of the document in the normal mode, and based on the detection signal, stops the rotation of the transport roller 22 and stands by for reading the document. Then, the conveyance of the document is restarted by the reading start signal sent from the copying machine main body H side. When the document passes over the surface of the transparent glass 11, the document is read by the document reading means 5.

The document reversing section 10 is located downstream of the document reading section, and has an introduction guide 27 that is open in a trumpet shape, a pair of reversing rollers 28 disposed in the vicinity thereof, and a rear side of the reversing roller 28. And the switchback path 29 provided in the switch. As shown in FIG. 3, pinch rollers 30 and 31 are provided at the entrance end and the exit end of the introduction guide 27, respectively, to assist the conveyance in the paper discharge path 32 and the feeding and discharging to the document reversing unit 10. In addition, the pinch roller 31 at the exit end also has a function as an inversion resist when reading the back surface of the document G. That is, the pinch roller 31 is in pressure contact with the transport roller 22 and rotates together with the drive of the transport roller 22.
Is stopped, and the leading end of the document G is brought into contact with the press-contact position 50 of both to align them. As described above, since the reversal registration is performed at the exit end of the document reversing unit 10, the document G
Does not slidably contact the peripheral surface of the transport roller 22. The reversing roller 28 can be opened and closed by a solenoid 33 and can also be rotated forward and backward by a sheet reversing motor 18. The forward and reverse rotations of the reversing roller 28 switch the document conveyance direction from the leading end to the trailing end. Before sending out. The reversing sensor S4 is located near the reversing roller 28.
Is arranged.

The document discharge section 9 is disposed below the paper feed tray 2 and has a pair of upper and lower guides 35 continuous from a paper discharge port 34 and a pair of paper discharge sections provided in the middle of the guide 35. It comprises a roller 36 and a discharge tray 37. The paper discharge roller 36 can be rotated forward and reverse by the pulse motor 25. A paper discharge sensor S5 is disposed near the paper discharge roller 36 to detect the discharge of the document.

Around the transport roller 22, flappers 38 and 39 for switching the transport direction of the original are arranged near the entrance of the original reversing section 10 and near the entrance of the original discharge section 9, respectively. As shown in FIG. 3, the former flapper 38 is disposed in the introduction guide 27 of the document reversing unit 10 sandwiched between the pinch rollers 30 and 31, and as shown in FIG. When switching to the route of FIG.
As shown in FIG. 7, there is a case where the path is switched to the path on the paper discharge path 32 side. A regulating flapper 53 that hangs down by its own weight is rotatably provided on the rotating shaft 52 of the flapper 38, and a guide piece 54 that rotates integrally with the regulating flapper 53 is provided on the opposite side. This guide piece 54
Is used to guide the leading edge of the document to the pressing position 50 between the transport roller 22 and the pinch roller 31 by contacting the leading edge of the document when the document is sent out from the document reversing unit 10. Can be prevented. In this embodiment, the regulating flapper 53 that hangs down by its own weight is used.
3, the guide piece 54 rises due to the weight of the regulating flapper 53 at the time of document reversal, as shown in FIG.
0. Further, as shown in FIG. 4, after the leading end of the document G reaches the pressing position 50, the guide piece 54
And a small document loop is formed to press the guide piece 54 toward the transport roller 22 side.
Since the force pushed back by the own weight of 3 acts, the leading end of the document G can be further digged into the press contact position 50 to enhance the resist effect.

A flapper 39 disposed in the vicinity of the downstream side of the pinch roller 31 switches between the paper feed path 6 and the original discharge section 9, and is switched by the solenoid 40 together with the flapper 38.

In this embodiment, a document evacuation path 41 branched downward from the paper feed path 6 is formed in the paper feed path 6 between the registration roller 7 and the pinch roller 23. The document evacuation path 41 is normally urged upward by a spring, and a guide plate that forms a curved evacuation path between the flapper 42 whose leading end projects into the paper supply path 6 and the lower surface of the flapper 42. 43. The flapper 42 is pushed downward when a document is conveyed thereon, and is sunk from the paper feed path 6, while when there is no document, the tip of the flapper 42 projects into the paper feed path 6 to open the evacuation path. ing.
The document evacuation path 41 is used in a so-called heterogeneous mixed mode in which documents of different sizes are mixed, detects the length of the document G conveyed from the paper supply tray 2 to the paper supply path 6, and temporarily reverses the document G. When the original is returned to a position where the leading end of the original is separated from the original reading section, the rear end of the original is stored.

Next, a case where one side of a document is read using the automatic document feeder having the above configuration and a case where both sides are read will be described separately.

First, one-sided reading of a document will be described with reference to FIGS. 6, 7 and 9. 6 and 9 (a)
As shown in the figure, when a plurality of sheets of the same size are set on the paper feed tray 2, the empty sensor is turned on to detect the original G, and at the same time, the size of the original is immediately detected by the size detection sensor S1, and The document size is transmitted to the H side. When the start button on the copying machine main body H side is turned on, the sheet feeding reversing motor 18 and the sheet feeding clutch 17
a, the arm 15 of the paper feed roller 14 is rotated, and the separation roller 16 and the paper feed roller 14 are rotated to separate the uppermost document among the documents G set on the paper feed tray 2. And send it out.

When the registration sensor S2 detects the leading edge of the document G, the rotation of the separation roller 16 is stopped after a lapse of time t1, and the leading edge of the document G is brought into contact with the registration roller 7 to perform alignment. After the alignment by the registration rollers 7 is performed, the apparatus waits for a time t2, and then rotates the registration rollers 7 to feed the document G to the paper feeding path 6. When the document G reaches the front of the transport roller 22 after a lapse of time t3, the pulse motor 25 is rotated forward to rotate the transport roller 22, and the document G is nipped between the transport roller 22 and the pinch rollers 23 and 24. Transport. At time t7 after the lead sensor S3 detects the leading end of the document G, the transport roller 22 stops and waits for scanning. As shown in FIG. 7, the pulse motor 25 is driven again by the reading start signal from the copying machine main body H, the conveying roller 22 is rotated, and the reading of the front side of the document G is started. The rotation speed of the transport roller 22 during reading is controlled at a low reading speed lower than the transport speed before reading. As shown in FIG. 9B, when the leading end of the document G enters the document discharge unit 9, the sheet discharge sensor S 5 detects the same, and the discharge roller 36, which is rotated by driving the pulse motor 25, like the transport roller 22. The paper is discharged onto the paper discharge tray 37.
As shown in FIG. 9C, the feeding of the next original G1 is started during the reading of the original, and the rotation of the pulse motor 25 is accelerated after a lapse of a predetermined time from the completion of the reading to perform the high-speed ejection. After t9, the mode is switched again to the speed-reduced discharge, and the discharge is completed.

Next, reading of both sides of a document will be described.
In this case, the lead sensor S3 detects the leading end of the document G,
Until the conveyance roller 22 stops and waits for scanning before reading the original, the same control as that shown in FIGS. 6 and 9A is performed. As shown in FIG. 8 and FIG.
At time t11 after the start of reading of the document G, the sheet reversing motor 18 is driven to rotate the reversing roller 28, the solenoid 40 is turned on, and both the flappers 38 and 39 are switched to form a path on the document reversing unit 10 side. Is done. When the leading end of the document G is conveyed into the switchback path 29, the regulating flapper 53 is pushed up and enters, and is detected by the reversing sensor S4. As shown in FIG. 10B, the entire document G whose front surface has been read is fed into the switchback path 29 by the high-speed conveyance of the conveyance roller 22 at time t8 after the read sensor S3 is turned off. The rear end of G is held between the reversing rollers 28. Next, the document G is switched back by rotating the reversing roller 28 in the reverse direction, and the document G is sent out with the rear end side at the top. Then, during a time t12 after the leading edge is detected by the reversing sensor S4, the leading edge of the document is guided to the exit side by the regulating flapper 53 and the guide piece 54, and the pinch roller 31 and the transport roller 22 disposed near the leading edge are pressed against each other. When the leading end of the document G abuts on the position 50, registration is performed and alignment is performed. After waiting for the time t13, the transport roller 22 rotates at a high speed to feed the original G to the paper feed path 6 and quickly transport the original G to the original reading position.
After the lead sensor S3 detects the leading edge of the document G, t1
After six hours, the transport roller 22 is stopped and the scanning is on standby. The original G is read by the reading start signal from the copying machine main body H side.
Is read, and as shown in FIG. 11D, the leading end of the document G is conveyed again into the document reversing unit 10. FIG.
As shown in FIG. 1E, when the reading is completed, the whole document is again fed into the switchback path 29 of the document reversing unit 10 by high-speed conveyance, and the rear end of the document G is sandwiched by the reversing roller 28. . Thereafter, the solenoid 40 is turned off, and both the flappers 38 and 39 are switched, so that the path on the side of the document discharge section 9 is formed. Therefore, as shown in FIG. The document G whose front and rear ends are reversed is discharged at a high speed by the conveying roller 22 and discharged from the discharge port 34 onto the discharge tray 37 to be completed. As shown in FIG. 5, the document reversing section 10 and the document discharge section 9 are connected by a path having a small radius of curvature. However, since the pinch roller 31 forcibly applies a conveying force in the sheet discharge direction. In addition, the paper can be smoothly discharged without lowering the conveying force. As described above, when reading both sides of the original G, the original G is turned over again and discharged in the same manner as in the case of single-sided reading, so that the order of the originals G stacked on the paper feed tray 2 is improved. The order of the documents G stacked on the discharge tray 37 can be matched.

The operation of the document reversing section in the case of reading a document in the mixed mode of different systems is the same as that in the above case.

As described above, the pinch roller that presses and conveys a document to and from the conveyance roller is disposed near the exit of the document reversing section, and the document that has been switched back by the document reversing section is moved by the force of the pinch roller. Since the sheet is sent to the reading unit or the document discharge unit, the path structure and the feed mechanism are simplified, and the size of the automatic document feeder itself can be reduced.

Further, since the conveying force is forcibly applied by the pinch roller, a sufficient original conveying force can be obtained even if the radius of curvature of the original discharging path is reduced.

Further, since the leading edge of the document sent from the document reversing section to the document reading section is brought into contact with and pressed against the pressing position with the transport roller, the leading edge of the document is surely not affected by the peripheral friction of the transport roller. Resist.

Furthermore, since the guide means for guiding the leading end of the document sent from the document reversing section to the pressure contact position between the transport roller and the pinch roller is provided, registration can be performed more smoothly.

[Brief description of the drawings]

FIG. 1 is an overall schematic diagram of an automatic document feeder according to the present invention.

FIG. 2 is an enlarged view of a main part of the automatic document feeder according to the present invention.

FIG. 3 is an enlarged view showing a structure near a document reversing unit.

FIG. 4 is an enlarged view showing a registration state near an exit of a document reversing unit.

FIG. 5 is an enlarged view of a discharge path from a document reversing unit to a document discharge unit.

FIG. 6 is a sheet feed timing chart when reading one side of a document.

FIG. 7 is a timing chart of conveyance / discharge at the time of single-sided reading of a document.

FIG. 8 is a transport / discharge timing chart when reading both sides of a document.

FIG. 9 is an explanatory diagram showing a flow of a document at the time of the single-sided reading.

FIG. 10 is an explanatory diagram showing a flow of a document at the time of front side reading in the duplex reading mode.

FIG. 11 is an explanatory diagram showing a flow of a document when reading the back side in the duplex reading mode.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 automatic document feeder 2 paper feed tray 5 document reading means 6 paper feed path (document transport path) 9 document discharge section 10 document reversing section 22 transport roller 31 pinch roller 32 discharge path (document transport path) 39 flapper 50 pressure contact Position 54 Guide piece G Original H Copier body

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yasuhito Watanabe 430-1, Kobayashi, Masuho-cho, Minamikoma-gun, Yamanashi Pref.

Claims (4)

[Claims] A document feeder, a document reading unit, a document discharge unit, a document feed path connecting them, and a feed roller for feeding a document along the feed path; In an automatic document feeder for sequentially feeding a document stacked on a paper feed unit to the document reading unit to read a document surface, and then discharging the document to the document discharge unit, A document reversing unit is provided between the document reversing unit and a pinch roller for pressing and conveying the document between the document reversing unit and the conveyance roller is provided near the exit of the document reversing unit. An automatic document feeder for reversing a leading end and a trailing end and sending the document to the document reading section or the document discharge section again. 2. The apparatus according to claim 1, wherein the pinch roller abuts a leading end of the document sent from the document reversing section to the document reading section at a pressure contact position with the transport roller and aligns the document. 2. The automatic document feeder according to claim 1, wherein the automatic document feeder is pressed and conveyed. 3. A guide means is provided near the upstream side of the pinch roller for guiding the leading end of the document sent from the document reversing section to a pressure contact position between the transport roller and the pinch roller. 3. The automatic document feeder according to claim 1, wherein: 4. A switching means for guiding a document sent out by the pinch roller to one of the document reading unit side and the document discharge unit side is provided near the downstream side of the pinch roller. 4. The automatic document feeder according to claim 1, wherein: