JP2943000B2 - Electrostatographic copier with automatic document feeder - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved technology of an electrophotographic copying machine with an automatic document feeder provided with an optical system movable exposure device.

[Conventional technology]

As the above-mentioned automatic document feeder, there are an upper feed type shown in FIG. 7 and a lower feed type shown in FIG.

The upper sheet feeding type automatic document feeder 71 shown in FIG.
A document conveying means 73 is provided above the transparent plate 72 for exposing the document, and one end of the document conveying means 73 in the conveying direction is arranged such that the originals b stacked on the document feeding table 74 are shifted from the highest one. Document feeding means 75 for feeding the document toward the document feeding means 73, and refeeding means for turning the document b discharged from the document feeding means 73 upside down and feeding it back to the document feeding means 73 And the original b via the path switching mechanism 77
A paper discharging means 79 for discharging the paper to the document tray 78 from the middle of the paper re-feeding means 76 is disposed at the other end of the document conveying means 73. Equipment 71
A document feeder 75 for feeding the stacked documents b from the lowest order to the document transporter 73 is provided at one end of the document transporter 73 in the transport direction. On the other end side of the means 73, there is provided a paper discharging means 79 for inverting the document b discharged from the document transporting means 73 and discharging it to a document tray 78 above the document transporting means 73; A sheet re-feeding means 76 for re-feeding the document b returned and conveyed by the means 73 to the document conveying means 73; and a document feeding means from the middle of the sheet re-feeding means 76 via a path switching mechanism 77. Paper discharge device that discharges paper to the 75 document feeder 74
80 is arranged on one end side of the document conveying means 73.

[Problems to be solved by the invention]

In the electrophotographic copying machine equipped with the automatic document feeder 71 having the above-described configuration, when copying one side of each of a plurality of documents b one by one or a plurality of sheets, A configuration in which the original b is transported to a predetermined position on the transparent plate 72 and the optical system movable exposure device 81 is reciprocated in a state where the original is fixed, but the original b is intermittently transported one by one and the transparent It takes a long copy time to temporarily stop on the plate 72, and especially when copying a plurality of sheets, it takes a long time to return the exposure device 81 to the home position every time the copy is made. This is a bottleneck in shortening the copying time.

On the other hand, in a double-sided copying type electrostatographic copying machine provided with a re-feeding device for reversing the copy sheet after single-sided copying and re-feeding it to the transfer unit, both sides of a plurality of originals are placed one by one or a In the case of copying one sheet at a time, the following copying mode is adopted.

That is, a copy form of the electrophotographic copying machine equipped with the upper sheet feeding type automatic document feeder 71 shown in FIG. 7 will be described with reference to FIGS. 9 (A) to 9 (I). In the upper sheet feeding type automatic document feeder 71, FIG.
As shown in FIG. 7, the originals b arranged in the page order are arranged such that the youngest ones in the page order face downward.
Stacked on 74. Here, ~ indicates a page of the document b.

When the print switch is operated, the uppermost document b on the document feeder 74 is once sent to the re-feeding means 76, and as shown by the phantom line in FIG. In the inverted state, the sheet is fed to the document conveying means 73 on the transparent plate 72, and as shown in FIG. 9B, the exposing device 81 reciprocates to perform exposure on the page, and also performs development, transfer, and fixing. Through the steps, the back side copy (page) of the original b is performed on the front side of the copy paper a.

Then, as shown in FIG. 7C, the copy paper a after the one-sided copy is transported by switchback and temporarily stored in the intermediate tray 82 in the main body of the copying machine, and the original b is returned to the re-feeding means 76. The document is transported to
It is re-fed to 73.

In this state, the copy paper a is fed from the intermediate tray 82, and the exposing device 81 reciprocates to perform exposure on the page, and after the development, transfer, and fixing steps, Front side copy of original b on back side of paper a
As shown in FIG. 3D, the copy paper a after the double-sided copying is discharged to the discharge tray 83, and the copied document b is discharged to the document tray 78.

When the copied document b is taken out to the document tray 78, the replacement document b to be copied next is sent to the re-feeding means 76, as shown in FIG. In this state, the original is fed back to the original conveying means 73 to exchange the original b, and as shown in FIG.
The document 81 is reciprocated to expose the page, and through the development, transfer, and fixing processes, the back side copy (page) of the replaced original b is performed on the front side of the copy paper a. As shown in FIG. 9G, the copy paper a after the single-sided copying is switched back and conveyed to the intermediate tray 82 of the copying machine main body, and the original b is returned to the re-feeding means 76 again. The sheet is fed and returned to the document conveying means 73 in a reversed state, and fed.

Then, as shown in FIG. 7H, the feeding of the copy paper a from the intermediate tray 82 is performed, and the exposing device 81 reciprocates to perform the exposure for the page, and the developing / developing operation is performed.
After the transfer and fixing processes, the front side copy (page) of the original b is performed on the back side of the copy paper a, and as shown in FIG. And the copied document b is discharged to the document tray 78.

Thereafter, the copy cycle after the document exchange shown in FIG. 8E is repeated, and by adopting the above-described paper feeding mode, the copy paper a having been duplex-copied as well as the duplex-copied original b has been moved upward. From the trays 78 and 83 in a state where the page order is aligned.

Here, when each of the plurality of originals b is exchanged and fed to the original conveying means 73 on the transparent plate 72, the original b is also sent to the re-feeding means 76 once and the front and back of the original Is required to take out the two-sided copy original b and the two-sided copy paper a to the trays 78 and 83 in a state where they are arranged in page order from the top. It is a bottleneck to shorten the copying time if the document b is turned upside down every time the document is replaced.

It should be noted that the lower-feeding type automatic document feeder shown in FIG.
In the electrostatographic copier provided with the document 71, the document b is placed on the document feeding table 74 of the document feeding means 75 so that the youngest one in the page order faces upward.
When the originals b are stacked and the originals b are exchanged, each original b is once fed to the original conveying means 73, and then the original b is returned and conveyed and sent to the re-feeding means 76. The document b to be copied is the same as the above-described electrophotographic copying machine with an automatic document feeder of the upper paper feed type, in which the sheet b is turned upside down and fed back to the document feeder 73.
The fact that the original b is once turned upside down every time is replaced is still a bottleneck in shortening the copying time.

The present invention has been made in view of the above circumstances, and according to the first invention, an automatic original capable of shortening a copying time when one side of an original is copied one by one or a plurality of sheets at a time. It is an object of the present invention to provide an electrostatographic copier with a transport device, and in the second invention, after shortening the copying time when copying one side of a document one by one or a plurality of sheets, It is an object of the present invention to provide an electrostatographic copying machine with an automatic document feeder capable of shortening the copying time in duplex copying of a plurality of documents.

[Means for solving the problem]

In order to achieve the above object, the first aspect of the present invention includes an exposure device for moving an optical system, and a document conveying means for introducing a document at a predetermined position on the transparent plate for exposing a document. Document feeding means for feeding a document to the document feeding means; refeeding means for reversing a document introduced into the document feeding means and refeeding the document to the document feeding means; and In an electrostatographic copying machine with an automatic document feeder in which a sheet discharging means for discharging a document to a document tray is arranged, a document circulating device for circulating the document is provided.
It is provided between the document feeder and the document transporter, forms an image reading section corresponding to the document circulation device, and allows the document to be introduced into the document circulation device and passes through the document circulation device. A path switching mechanism for switching between the original state and the original state is provided, and the exposure device is configured to be able to be fixedly exposed at a position facing the image reading unit. The present invention is characterized in that a switchback mechanism is provided which causes the document feeder to feed the document after waiting for the previous document to be discharged.

The second invention includes an exposure device for moving the optical system, and a re-feed device for reversing the copy sheet after one-sided copying and re-feeding the copy sheet to the transfer section. Document transport means for introducing a document at a predetermined position on the transparent plate,
Further, a document feeder for feeding a document to the document feeder, a refeeder for reversing a document introduced to the document feeder upside down and refeeding the document feeder,
In an electrostatographic copying machine with an automatic document feeder in which a sheet discharging means for discharging a document to a document tray is provided, a document circulating device for circulating the document is provided by a document feeding means and a document feeding means. And an image reading unit corresponding to the document circulation device, and
A path switching mechanism for switching between a state in which the document is introduced into the document circulation device and a state in which the document is passed through the document circulation device is provided, and the exposure device is configured to be capable of being fixedly exposed at a position facing an image reading unit. The present invention is characterized in that a switchback mechanism is provided for turning the original introduced into the original circulation device upside down and feeding the original to the original conveying means.

[Action]

According to the first aspect, the exposure device faces the image reading unit of the document circulating device, and the document is fed so as to pass through the document circulating device. Exposure mode can be set, and when copying one side of the document one sheet at a time, taking the above exposure mode enables continuous feeding of the document, thus shortening the copying time. Is done.

Alternatively, an exposure device faces an image reading unit of the document circulation device, and a document is introduced into the document circulation device, and the document is circulated by the image reading unit, thereby providing optical rotation by so-called document circulation. A system-fixed exposure mode can be set, and when copying one side of a document a plurality of times, the above-described exposure mode allows the copying time to be equivalent to returning the exposure apparatus to the home position. Can be shortened. Further, in the first invention, a re-feeding unit for reversing the original introduced into the original conveying unit and re-feeding the original to the original conveying unit, and reversing the original introduced into the original circulating apparatus and reversing the original. Since there is provided a switchback mechanism for feeding the original to the original conveying means after waiting for the previous original to be discharged, it is possible to shorten the copying time in duplex copying of a plurality of originals.

According to the second aspect of the invention, when the exposure device faces the image reading unit of the document circulation device and the document is fed so as to pass through the document circulation device, it is possible to copy one side of the document one by one. Or shortening the copying time of the original, or exposing the exposure device to the image reading section of the original circulating device, and introducing the original into the original circulating device to circulate the original. Copying time for copying can be reduced.

Further, before feeding the document to the document feeder, it is possible to introduce the document into the document circulating device and turn it upside down by switchback to feed the document to the document feeder, Therefore, for example, before the double-sided copying of the previously fed document is completed, the replacement document to be fed next is turned upside down in advance, so that the copying time for duplex printing of a plurality of documents is Is achieved.

〔Example〕

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

<First Embodiment> FIG. 3 shows an electrostatographic copying machine equipped with an automatic document feeder 1 of an upper paper feeding type, and a photoconductor is mounted on a copying machine main body 3 provided with a transparent plate 2 for reading an image at the upper part. 4 and
Around the photosensitive member 4, a charging unit 5, a developing unit 6, a transfer unit 7, a copy paper separating unit 8, and a cleaning unit 9 are arranged, and an optical system fixed exposure is performed by moving a document on the transparent plate 2. An exposure device 10 that can be switched between an exposure mode and an exposure mode for moving an optical system by fixing an original on the transparent plate 2 is disposed in an upper space of the copying machine body 3 and a cassette case.
A sheet feeding and conveying device for conveying the copy paper a in 11 to the transfer section 7
12, a paper discharge transport device 14 for transporting the copied and separated copy paper a to the fixing unit 13, and a discharge tray 15 for transferring the fixed copy paper a to the discharge tray 15.
A discharge roller pair 16 for discharging the toner to the printer is provided.

A switchback mechanism is provided in the lower space of the copying machine main body 3 and provided with an intermediate tray 18 provided with a double feed preventing paper feeder 17 and selectively transporting the fixed copy paper a to the intermediate tray 18. 19 is the fixing unit 13 and the discharge roller pair 16
And a conveying device 20 for feeding the single-sided copy paper a stored in the intermediate tray 18 to the sheet feeding / conveying device 12 is provided. Can be re-fed to the transfer section 7 by reversing the copy paper a.

As shown in FIGS. 1 and 2, the automatic document feeder 1 includes a document feeder 21 for introducing a document b to a predetermined position on the transparent plate 2, and a document b supplied to the document feeder 21. A document feeder 22 for feeding paper, and a document b introduced into the document feeder 21 is turned upside down so that the document feeder 21
Re-feeding means 23 for re-feeding paper, and a path switching mechanism
Discharge means 26 for discharging the document b to the document tray 25 from the middle of the re-feed means 23 through 24 is provided in a housing 27 which can be opened and closed around a horizontal axis on the rear side of the copying machine main body 3, and Document circulation device 28 for circulating document b
Is provided between the document feeding means 22 and the document conveying means 21,
Further, an image reading unit 29 formed of a current plate is formed corresponding to the document circulating device 28, and the document b introduced into the document circulating device 28 is turned upside down and fed to the document conveying means 21. A switchback mechanism 30 is provided.

The exposure device 10 that can be switched between the exposure mode in which the optical system is fixed and the exposure mode in which the optical system is moved is configured to be movable to a position A facing the image reading unit 29.

According to the above configuration, the exposure device 10 is
Exposure device to expose the image reading unit 29
10 is positioned at the exposure mode position A fixed to the optical system, and the document b is continuously fed from the document feeding means 22 at a predetermined timing. From the document conveying means 21 to the re-feeding means 23
By discharging the copy paper a from the cassette case 11 at the same predetermined timing and fixing the exposure, development, transfer, and fixing, the original is discharged. Under the continuous feeding of b, one side of a plurality of originals b can be continuously copied one by one.

Alternatively, the exposing device 10 is positioned at the exposure mode position B where the optical system is fixed, and the document b is continuously fed from the document circulating device 28 to the document conveying means 21 at a predetermined timing. Refeeding means 23 and paper discharging means 26
Through the cassette tray 11 at the same time and at the same time, exposing, developing, transferring and fixing the original, thereby continuously feeding the original b. Below, a plurality of originals b
Can be continuously copied one by one.

Further, after the exposing device 10 is positioned at the position A facing the image reading section 29, the document b is introduced from the document feeding means 22 to the document circulation device 28 at a predetermined timing, and the document b is copied. The paper is circulated and moved by the number of sheets, and a plurality of sheets of copy paper a are continuously fed from the cassette case 11 at the same predetermined timing, and the steps of exposure, development, transfer, and fixing are performed to perform one-sided copying. While the subsequent copy paper a is discharged to the paper discharge tray 15, the original b which has completed the circulating movement
From the original conveying means 21 to the paper re-feeding means 23 and the paper discharging means.
26 to a document tray 25, and if necessary, simultaneously with the discharge of the document b, a document b to be copied next is fed to a document circulating device 28.
After shortening the copying time for returning the document 10 to the home position, one side of a plurality of originals b can be continuously copied one by one.

Further, a reduction in the copying time when two-sided copying of a plurality of originals b is achieved is achieved as follows.

That is, after the exposure apparatus 10 is set to the exposure mode for moving the optical system, as shown in FIG. The originals b are stacked and placed on the original feeding table 31 of the paper means 22, and the uppermost original b is sent from the original conveying means 21 to the re-feeding means 23 to be turned upside down (see the imaginary line in FIG. 3A). The document b is fed to the document conveying means 21 on the transparent plate 2 with the page turned downward, and the transfer paper a is transferred from the cassette case 11 at a predetermined timing as shown in FIG. And the optical system of the exposure device 10 is reciprocated to perform exposure on the page, and to perform development, transfer and fixing steps. Have the page copied.

Next, as shown in FIG. 2C, the copy paper a after the single-sided copying is fed to the switchback mechanism 19 to be stocked in the intermediate tray 18, and the original b is fed to the re-feeding means 23.
And the document is turned upside down, and the document is re-fed to the document conveying means 21 with the page of the document b facing downward, and
During this time, the original b to be copied next is fed to the switchback mechanism 30 through the original circulation device 28, and the original b is turned upside down and kept in the switchback mechanism 30.

Then, at a predetermined timing, the copy paper a is re-fed from the intermediate tray 18 to the transfer unit 7, and the exposing device 10 is reciprocated to perform exposure on the page, and a developing / transfer / fixing process is performed. To make a copy of the first page of the document b on the back side of the copy paper a, and discharge the copy paper a after double-sided copying to the paper output tray 15 as shown in FIG. The copied document b is discharged to the document tray 25, and simultaneously with the discharge of the document b, the document b to be replaced, which is turned over and turned on standby by the switchback mechanism 30, is supplied to the document conveying means 21. Make it paper.

Therefore, since the original b to be exchanged is also turned upside down in advance, as shown in FIGS. 9 (D) and 9 (E), the time for turning over the exchanged original b after discharging the copied original b is shortened. This is unnecessary, and copying of the original b is immediately performed at the same time when the original b to be copied is exchanged.

Next, as shown in FIG. 4 (E), the reverse side (page) of the replacement document b is performed on the front side of the copy sheet a, and the copy sheet a after the single-sided copy is switched back and conveyed to the intermediate tray. 18
And the original b is sent to the re-feeding means 23 to re-feed the original b to the original conveying means 21 with the page facing downward.

Then, as shown in FIG. 4 (F), the copy paper a after one-sided copying is fed again from the intermediate tray 18 to the transfer section 7 at a predetermined timing, and is subjected to a predetermined exposure, development, transfer, The fixing process is performed, and the copy of the first page of the document b is performed on the back side of the copy paper a, and the copy paper a after the double-side copy is placed on the discharge tray 15 as shown in FIG. Let it drain,
The copied document b is discharged to the document tray 25.

The above is a description of double-sided copying of two originals b. However, in the third and subsequent double-sided copying of three or more originals b, during the copying process shown in FIG. As shown in FIG. 4C, the document b to be exchanged is fed from the document circulation device 28 to the switchback mechanism 30, and the switchback mechanism 30 causes the document b to stand by in an inverted state. During the document discharging process shown in FIG. 4F, as shown in FIG. 4D, a mode is adopted in which the document b, which has been made to stand by by the switchback mechanism 30, is fed to the document conveying means 21. Therefore, every time the original b to be copied is replaced, the time for temporarily turning the original b upside down is not wasted, and the copy time is shortened.

Hereinafter, a schematic structure of various units in the automatic document feeder 1 will be described with reference to FIGS.

First, the document conveying means 21 is configured by winding a conveying belt 32 also serving as a document pressing member around a roller 33, and the document feeding means 22 includes
A feed roller 34 for sequentially feeding out the uppermost one of the originals b stacked and placed on the original feeder table 31, and a pair of registration rollers 35 for feeding the original b to the original conveying means 21 at a predetermined timing. Become.

The re-feeding means 23 is provided with a re-feeding path 37 around the document conveying roller 36, and at the path start end of the re-feeding path 37, the leading end regulating member 38 of the document b is switched to the release state. It is provided freely.

The document circulating device 28 includes a pair of rollers 39
0, and a pressing roller 41 for bringing a part of the transport belt 40 into contact with the image reading unit 29 is provided. Further, an endless document circulation path 42 having the contact part of the transport belt 40 as a part of the path. A state in which the document b is introduced into the endless document circulation path 42 on the downstream side of the conveyance belt 40,
A path switching mechanism 43 is provided for switching to a state in which the document is passed through the document circulation path 42 and fed to the document conveying means 21.

The switchback mechanism 30 provides a document feed roller 44 constituting a part of the endless document circulation path 42 so as to be able to drive forward and reverse, and a paper feed roller 45 corresponding to the document feed roller 44, and A document take-out path 47 is branched to the endless document circulation path 42 via a path switching claw 46, and a document receiving table 48 is connected to the document taking-out path 47. A document return path 49 for returning the document b to the document conveying means 21 and feeding the document is provided.

Second Embodiment FIGS. 5 and 6 show an automatic document feeder 1 according to a second embodiment.

This is a so-called lower feed type, in which a document feed table 31 is provided obliquely above the document feed means 21 and a sheet feed roller 34 and a registration roller A pair 35 is provided to constitute the document feeder 22, a document circulator 28 is provided between the document feeder 22 and the document transporter 21, and an image is read corresponding to the document circulator 28. A state where the document b is introduced into the document circulating device 28, and a document conveying unit that passes through the document circulating device 28
A path switching mechanism 43 for switching to a state in which the document is fed to the document feeder 21 is provided.The switchback mechanism 30 for turning the document b introduced into the document circulation device 28 upside down and feeding the document to the document feeder 21 is provided. It is provided.

Then, in the vicinity of the lower side of the document feeder 22, a re-feeding unit 23 for reversing the front and back of the document b returned and transported from the document transporter 21 and re-feeding the document b to the document transporter 21.
And a paper discharging device 51 for discharging the document b to the document feeder table 31 from the middle of the path of the re-feeding means 23 via the path switching mechanism 50, and the document conveying means There is provided a paper discharging means 26 for discharging paper to the original tray 25 on the upper part 21.

Note that the exposure device 10 that can be switched between an exposure mode in which the optical system is fixed and an exposure mode in which the optical system is moved is configured to be movable to a position A facing the image reading unit 29.

The document circulating device 28 is provided with a pressing roller 41 for winding a transport belt 40 around a pair of rollers 39, 39, and bringing a part of the transport belt 40 into contact with the image reading unit 29, and An endless first document circulation path 42A having a short path configuration having a contact portion as a part of the path is arranged around the conveyance belt 40, and the first document circulation path 42A is bypassed via a path switching mechanism 52 via a path switching mechanism 52. To form a second document circulation path 42B whose path is slightly longer than the first document circulation path 42A.

The path length of the first document circulation path 42A is set to be slightly longer than the length of the A4 size document b in the short direction, for example, and the path length of the second document circulation path 42B is, for example, If the length of the A4 size document b is set to be slightly longer than the length in the longitudinal direction, and one side of the plurality of documents b is copied a plurality of times, the By taking the shortest path, it is considered that the copying time can be reduced as much as possible.

The switchback mechanism 30 is configured by branching a document take-out path 47 via two path switching claws 53 and 54 in the middle of the path of the document circulation device 28, specifically, near the periphery of the document feed roller 44. One of the path switching claws 53 is in a state in which the document b is fed to the circulation paths 42A and 42B and the document take-out path 4
7, and the other path switching claw 54 reverses the original b introduced into the original take-out path 47 from the circulation paths 42A and 42B, and places the original b at the rear end. The paper is fed again from the side to the circulation paths 42A and 42B.

In the above configuration, when copying one side of each of the plurality of originals b one by one, and when copying one side of the original b a plurality of times, the same copy mode as that of the configuration of the first embodiment described above is used. Is taken.

The two-sided copying for a plurality of originals b is different in that the originals b are stacked and placed on the original feeding table 31 of the original feeding means 22 such that the youngest ones in the page order face upward. Takes a form similar to that of the configuration of the first embodiment described above.

That is, while the first document b is being copied, the next document b to be fed is introduced into the switchback mechanism 30, and
In this embodiment, the document b whose front and back are reversed is fed to the document conveying means 21 following the discharge of the first document b.

In both the first and second embodiments, when the first document b is turned upside down and fed to the document conveying means 21, the document b is fed to the re-feeding means 23. However, the first document b is switched from the document circulation device 28 to the switchback mechanism.
Alternatively, the original b may be fed to the original conveying means 21 by feeding the original to the original 30 and then turning over the original b by the switchback mechanism 30.

Also, the optical system movable exposure apparatus 10 is moved to the exposure mode position B.
, The exposure device 10 is fixedly exposed, and the exposure device 10 is positioned at a position A facing the image reading section 29 of the document circulation device 28.
However, the optical system movable type exposure device 10 may be configured to be capable of fixed exposure only at the position A facing the image reading section 29 of the document circulation device 28.

Further, in the automatic document feeder 1 shown in FIG.
The document circulating device 28 irrespective of the presence or absence of the switchback mechanism 30 can be provided between the document conveying means 21 and the paper discharging means 26.

〔The invention's effect〕

As described above, according to the electrostatographic copying machine with the automatic document feeder of the first invention, the exposure device faces the image reading unit of the document circulating device, and the document is circulated in the image reading unit. A plurality of copies on one side of a document can be achieved in a so-called exposure mode in which the optical system is fixed by moving the document, and the copying time is shortened relative to the time required to return the exposure device to the home position as compared with the case of moving the optical system. be able to.

Alternatively, if necessary, the exposing device faces the image reading unit of the document circulating device, and the document is fed so as to pass through the document circulating device. Each time continuous copying is achieved, the copying time can be greatly reduced. Further, in the first invention, a re-feeding unit for reversing the original introduced into the original conveying unit and re-feeding the original to the original conveying unit, and reversing the original introduced into the original circulating device to reverse the original. Since there is provided a switchback mechanism for feeding the original to the original conveying means after waiting for the previous original to be discharged, it is possible to shorten the copying time in duplex copying of a plurality of originals.

According to the second aspect of the present invention, the original introduced into the original circulation device can be turned over by switchback, and the original can be fed to the original conveying means on the transparent plate. When performing two-sided copying of a document, for example, before the two-sided copying of the previously fed document is completed, the replacement document to be fed next is turned upside down in advance, so that the conventional Thus, every time the original to be copied is exchanged, the original can be turned upside down once and the waste time for feeding the original to the original conveying means can be eliminated, thereby greatly reducing the time required for duplex copying of a plurality of originals. Can be shortened.

[Brief description of the drawings]

1 to 4 show a first embodiment, FIG. 1 is an overall view showing an automatic document feeder of an upper feed type, FIG. 2 is a detailed view of a main part thereof, and FIG. Overall view of an electrostatographic copier equipped with a paper type automatic document feeder, FIG.
FIG. 7G is an explanatory diagram of a sheet feeding mode during duplex copying. 5 and 6 show a second embodiment, FIG. 5 is an overall view showing a lower feed type automatic document feeder, and FIG. 6 is a detailed view of a main part thereof. 7 and 8 show a conventional example, FIG. 7 is an overall view showing an upper sheet feeding type automatic document feeder, and FIG. 8 is an overall view showing a lower sheet feeding type automatic document feeder. . 9 (A) to 9 (I) are illustrations showing a paper feed mode during duplex copying for the automatic document feeder shown in FIG. 2 ... Transparent plate, 7 ... Transfer section, 10 ... Exposure device, 21 ...
Document conveying means, 22: Document feeding means, 23: Re-feeding means, 25: Document tray, 26: Discharging means, 28: Document circulation device, 29: Image reading unit, 30 ... Switchback mechanism, 43: Path switching mechanism, a: Copy paper, b:
Manuscript.

Continuation of the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) B65H 83/00-85/00 B65H 29/58

Claims (2)

(57) [Claims] An exposing device for moving an optical system, a document conveying means for introducing a document at a predetermined position on the transparent plate for exposing a document, and Document feeding means for feeding a document, a sheet re-feeding means for reversing a document introduced into the document feeding means and re-feeding the document to the document feeding means, and discharging the document to a document tray In an electrophotographic copying machine with an automatic document feeder having a paper discharge means, a document circulating device for circulating the document is provided between the document feed means and the document transport means, and the document circulating means is provided. An image reading unit is formed corresponding to the apparatus, and a path switching mechanism for switching between a state in which the document is introduced into the document circulating apparatus and a state in which the document is passed through the document circulating apparatus is provided. , And can be fixedly exposed at a position facing the original document.Furthermore, the document introduced into the document circulation device is turned upside down, and the document is made to stand by until the previous document is discharged. An electrophotographic copying machine with an automatic document feeder, comprising a switchback mechanism for feeding paper. 2. An exposure apparatus for moving an optical system, and a refeeding apparatus for reversing a copy sheet after one-sided copying and re-feeding the copy sheet to a transfer section. Document feeding means for introducing a document at a predetermined position on a transparent plate is further provided.Document feeding means for feeding a document to the document feeding means, and a document fed to the document feeding means is turned over. The document is circulated in an electrophotographic copying machine with an automatic document feeder in which a sheet re-feeding means for re-feeding the document to the document feeding means and a sheet discharging means for discharging the document to a document tray are arranged. A document circulating device is provided between the document feeding device and the document conveying device, an image reading section is formed corresponding to the document circulating device, and the document is introduced into the document circulating device. And the state of passing through the document circulation device In addition to providing a path switching mechanism for switching, the exposure device is configured to be able to be fixedly exposed at a position facing the image reading unit, while a document introduced into the document circulation device is turned upside down and fed to the document conveying means. An electrostatographic copying machine with an automatic document feeder, comprising a switchback mechanism for causing the electrophotographic copying machine to have a switchback mechanism.