JPH0555863B2 - - Google Patents

Description

[Detailed description of the invention] Technical field The present invention relates to a double-sided copying machine.

PRIOR ART Conventionally, there are various types of double-sided copying machines, but generally, as shown in Japanese Patent Publication No. 49-36264, a single photosensitive drum is used to transport the transfer paper. The path is formed in a loop shape including a double-sided tray and the like. As a result, there is a high probability that the transfer paper will jam, leading to frequent troubles, and the time required for double-sided copying is long.

In this regard, U.S. Patent No. 3536398 and
There is also a double-sided copying machine using two photosensitive drums, as shown in Japanese Patent No. 161559. However, even this method is not sufficient, as it requires complicated improvements to the optical system in order to align the image orientations of the front and back copies. Furthermore, even with a double-sided copying machine, there are many cases where single-sided copying is required. In this regard, although single-sided copying is of course possible with the conventional method, since the transfer paper is conveyed through the same long path as in double-sided copying, the copying time becomes longer and longer. Furthermore, even if it has two photosensitive drums, it only functions as one copying machine, and its processing capacity can be said to be low.

Purpose The present invention has been made in view of the above points, and enables double-sided copying with a reduction in transfer paper jams and shortened double-sided copying time, while also shortening the copying time and improving processing capacity for single-sided copying. The object of the present invention is to obtain a new double-sided copying machine that can be made larger in size.

Configuration One embodiment of the present invention will be described based on the drawings. First, two photoreceptor drums 1a, which serve as image recording bodies,
1b are juxtaposed in the front and rear rows. Chargers 2a, 2b and eraser 3 are applied to these photosensitive drums 1a, 1b according to an electrophotographic process.
a, 3b, optical systems 5a, 5b that expose and image the originals on contact glasses 4a, 4b, and a developing device 6.
a, 6b, paper feed sections 8a, 8 for transfer paper 7a, 7b
b, separation transfer chargers 9a, 9b, cleaning devices 10a, 10b, static eliminators 11a, 11
b. Fixing devices 12a and 12b are provided.
Here, automatic document feeders 13a and 13b are provided on contact glasses 4a and 4b.
These automatic document feeders 13a and 13b are connected to the document table 1.
Originals 15a, 15 set on 4a, 14b
It mainly consists of conveyor belts 16a and 16b for conveying the materials b, and also includes recycling paths 17a and 17b. In this way, the front image forming means 1
8a and a subsequent image forming means 18b are formed.

Such front and rear image forming means 18a, 18
b is connected by a transfer paper transport path 20 and an original transport path 21. First, the transfer paper conveyance path 20 connects the photosensitive drums 1a and 1b to convey the transfer paper 7a from the front side to the rear side, and is formed in a substantially straight line. have This transfer paper reversing device 22 rotates one sheet of transfer paper 7.
The transfer paper reversing conveyance device 23 is capable of reversing only the transfer paper 7a and immediately transporting it to the subsequent stage side, and the transfer paper reversing intermediate tray 24 is located below it and can accommodate a plurality of sheets of transfer paper 7a, and can then reversely feed the paper. It is configured. As is well known, the transfer sheet reversing conveyance device 23 is composed of three roller pairs 25 and a reversing path 26, and as shown in the figure, the upper side 2 of the three roller pairs 25
If the two follower rollers open the reversing path 26, the transfer paper 7a enters the reversing path 26 and is reversed and conveyed, but if the reversing path 26 is closed, the transfer paper 7a simply passes through without being reversed. It is what it is. The transfer paper reversing intermediate tray 24 is provided with a partition pressure plate 27 and a paper feed roller 28 . A switching claw 29 is provided for selectively switching between the transfer paper reversing and conveying device 23 side and the transfer paper reversing intermediate tray 24 side. Furthermore, the transfer paper reversing conveyance device 23
At the rear stage, a second intermediate tray 30 capable of storing the inverted transfer paper 7a is provided in parallel with the transfer paper conveyance path 20 together with a paper feed roller 31, and a switching claw 32 is provided for selectively switching between the two. It is being On the other hand, the document conveyance path 21 is also
It connects between 3a and 13b and transports the original 15a from the front side to the rear side, and is formed in a substantially straight line, and a document reversing device 35 is provided along the way. The document reversing device 35, like the transfer sheet reversing conveyance station 23, is composed of three roller pairs 36 and a reversing path 37, and the reversing path 37 also serves as manual document feed. Here, a switching claw 38 for selectively switching between the document transport path 21 side and the recycle path 17a side is provided at the rear stage of the automatic document feeder 13a, and a paper discharge tray 39 provided for the automatic document feeder 13a is provided. A switching claw 40 is provided for selectively switching between the recycle path 17a side and the recycle path 17a side.

Next, the fixing station 12b on the photosensitive drum 1b side
At the rear stage, there is a reversing discharge device 5 having three roller pairs 50, a reversing path 51, and a paper folding stopper 52.
3 is provided, and a paper discharge tray 55 and a sorter 56, which are selected by a switching claw 54, are provided at the subsequent stage. Further, a paper discharge tray 60 is provided downstream of the automatic document feeder 13b via a reversal discharge device 59 having three roller pairs 57 and a reversal path 58. Reference numeral 61 is a switching claw for selectively switching between the reversing and discharging device 59 side and the recycle path 17b side.

Note that 70 is a manual paper feed section provided in parallel with the paper feed section 8a.

With such a configuration, the double-sided copying machine of this embodiment can handle various aspects. Although switches, control circuits, etc. are not particularly shown here, various modes can be set freely.

First, consider the 1-1 duplex copy mode in which one double-sided copy is made from one double-sided original. At this time, the original 15a is set on the original table 14a.
However, when copying starts, this document 15a
is fed, conveyed onto the contact glass 4a by the conveyor belt 16a, and stopped. Therefore, optical system 5
A is the photosensitive drum 1 which is rotating while exposing and scanning the surface of the document 15a on the contact glass 4a.
A latent image is formed on a. This latent image is transferred to the developing device 6a.
After being developed, the image is transferred to a transfer paper 7a fed at a predetermined timing from the paper feed section 8a side by the action of a separation transfer charger 9a. Then, the image passes through the fixing device 12a and the surface copying onto the transfer paper 7a is completed. When the front side copy is completed in this way, the original 15a on the contact glass 4a is conveyed by the conveyor belt 16a to the original reversing device 35, and is turned over by the original reversing device 35 so that the back side is facing down. Head to the 13a side,
The contact glass 4 is transported by the conveyor belt 16a.
b. At the same time, the next document 15a is set on the contact glass 4a by the automatic document feeder 13a. On the other hand, the transfer paper 7a on which the front surface has been copied is sent from the fixing device 12a to the transfer paper reversing conveyance device 23, where it is reversed so that the uncopied back side faces up, passes through the transfer paper conveyance path 20, and is delivered to the photoreceptor drum 1b. It will be in a standby state. Therefore, backside copying is performed on the photosensitive drum 1b side (at this time, frontside copying of the next document is performed on the photosensitive drum 1a side). That is, the back side of the original 15a set on the contact glass 4b is exposed and scanned by the optical system 5b to form a latent image on the photoreceptor drum 1b, which is then developed, transferred, and scanned.
According to the fixing process, a back side copy is formed on the back side of the front side copy paper 7a. Then, the original 15a and the transfer paper 7a on which both sides have been copied are discharged to paper discharge trays 60, 55, etc. (they are reversed or the sorter 56 is selected as necessary).

Next, consider a repeat duplex copy mode in which a predetermined number of double-sided copies, which are set to repeat, are made from one double-sided original, although this mode is also a double-sided original-duplex copy mode. Basically, it is the same as in the 1-1 double-sided copy mode described above, but the switching claw 29 is switched and the transfer paper reversing intermediate tray 24 is selected instead of the transfer paper reversing conveyance device 23. First, a copying operation is repeated on the photosensitive drum 1a side for the number of copies of the original 15a fed and set on the contact glass 4a by the automatic document feeder 13a, thereby creating a front side copy. The transfer paper 7a on which the front side has been copied is sequentially discharged to the transfer paper reversing intermediate tray 24 and temporarily stored therein. When the surface copying for the number of repeat sheets is completed, the contact glass 4a
The upper document 15a is conveyed and set on the contact glass 4b while being reversed by the document reversing device 35. On the other hand, a paper discharge number detection means is provided in the transfer paper reversing intermediate tray 24 or in the conveyance path immediately before it, and when it is detected that the transfer paper 7a corresponding to the number of repeat sheets has been stored, the partition pressure plate 27 is activated to feed the paper. It switches to the roller 28 side and enters a standby state for paper feeding to the photosensitive drum 1b side. Therefore, the photosensitive drum 1b is
Back side copying will be performed on the side, and the transfer paper 7a on which the front side has been copied is fed one by one in an inverted state from the intermediate tray 24 by the paper feed roller 28, thereby completing the double-sided copying.

Also, in the double-sided copy mode, consider the case where a double-sided copy is obtained from a single-sided original. In this case also 1
There are a -1 double-sided copy mode and a repeat double-sided copy mode, and in the former case, the transfer paper reversal conveyance device 23 is selected, and in the latter case, the transfer paper reversal intermediate tray 24 is selected. On the other hand, regarding the document side, first, all documents are transferred to the automatic document feeder 13.
A is set on the document table 14a, and after the front side copying of the odd-numbered (front side) document 15a is completed on the photosensitive drum 1a side, this contact glass 4
The odd-numbered originals 15a on top a are transferred to the original transport path 21-
While the paper is immediately ejected through the contact glass 4b, the next even-numbered paper (for the back side) on the document table 14a is ejected immediately.
There is a method in which the original 15a is passed through the contact glass 4a and the original transport path 21, and then transported and set on the contact glass 4b for back side copying. That is, the document reversing device 35 becomes inactive.

In any case, in the double-sided copy mode as described above, the front-stage image forming means 18a creates a front-side copy mode, the rear-stage image forming means 18b creates a back-side copy, and both image forming means 18a, 18
Double-sided copying is completed by the linked operation of b. In other words, both image forming means 18 in the present invention
Double-sided copying is performed as one aspect of the linked use mode of a and 18b. In this case, since the transfer paper 7a is conveyed from the photoreceptor drum 1a side to the photoreceptor drum 1b side by the substantially straight and short transfer paper conveyance path 20, the probability of occurrence of a transfer paper jam is reduced and the copying speed is also improved. It is something. This also applies to the document side, and since the document transport path 21 connecting the automatic document feeders 13a and 13b is substantially straight and short, document jams are reduced. Further, after the surface copying of the transfer paper 7a is performed, the transfer paper 7a is reversed by the transfer paper reversing device 23 and conveyed to the photoreceptor drum 1b side.
This is the same as when the paper is fed toward the photosensitive drums 1a and 1b, and the arrangement of the copying process components such as the optical systems 5a and 5b can be made completely the same on both the photosensitive drums 1a and 1b. Therefore, there is no need to make complicated improvements to the optical system, such as adjusting the orientation of images, as in the past, and the system can be simplified. Furthermore, as a result, it is possible to adopt a method in which originals are simply passed from the front side to the rear side, and by using the automatic document feeders 13a and 13b, a large amount of double-sided copying can be performed automatically and in a short time. be.

Furthermore, a single-sided copy mode can also be selected, and various single-sided copy processes can be performed. First, in the double-sided copying machine of this embodiment, the front and rear image forming means 18
Although double-sided copying can be achieved by linking the image forming means 18a and 18b, the front and rear image forming means 18a and 18b can each be driven independently by means of a changeover switch (not shown), and an independent use mode can also be selected. It is. In other words, there are two independent copying machines, and each automatic document feeder 13a, 1
Set originals 15a and 15b on transfer paper 7
By feeding sheets a and 7b from the respective paper feed sections 8a and 8b, one-sided copying can be performed simultaneously using the respective photosensitive drums 1a and 1b, optical systems 5a and 5b, etc. in parallel. Therefore, when copying a large amount, if the copying is done by dividing the copying process, the time will be halved, resulting in high-speed processing. In this case, the original 15a
is discharged to the paper discharge tray 39, and the transfer paper 7a is discharged to the transfer paper reversing intermediate tray 24. In other words, since the transfer sheets 7a and 7b only need a short conveyance path, which is different from the case of double-sided copying, the copying time is also shortened.

Incidentally, the mode in which both image forming means are used in conjunction with each other is not only capable of double-sided copy processing, but also allows special single-sided copying and other processing by taking advantage of the features of the linked combination. For example, you may want to make a single-sided copy of a double-sided original. In this case, set the double-sided original on the document table 14a, and copy the front side of the original onto the transfer paper 7a on the photosensitive drum 1a side in the same way as when copying the front side. , this transfer paper 7a is discharged to the transfer paper reversing intermediate tray 24. After this operation is completed, the original 15a on the contact glass 4a is transferred to the original reversing device 35.
It is then conveyed and set on the contact glass 4b. Then, one-sided copying is performed on the back side of the original 15a onto the transfer paper 7b on the photosensitive drum 1b side. By repeating the same operation, double-sided original-single-sided copy processing can be performed automatically.

In addition, even when copying the same single-sided copy, there are cases where multiple copying is required, in which multiple original contents are overlapped and copied on the same copy side, but in this case, after performing the first single-sided copy on the transfer paper 7a, this transfer It is sufficient to send the paper 7a to the photosensitive drum 1b in a non-inverted state through the transfer paper reversing conveyance device 23 which is in an inactive state, and to perform a second single-sided copy on the document on the contact glass 4b.

Furthermore, for example, there are cases where it is desired to copy two B5-sized originals onto one B4-sized sheet, but in this case, the front-stage image forming means 18a copies each original onto half of the B4-sized transfer paper 7a. Then, the transfer paper 7a is sent to the photosensitive drum 1b side without being reversed, and the second document is copied onto the remaining half of the transfer paper 7a on the rear image forming means 18b side. This can also be applied to double-sided originals, allowing double-sided originals to be made into double-sided copies.

In this way, as the double-sided image forming means linked use mode, it is possible to perform not only double-sided copying but also single-sided copying such as double-sided original-single-sided copying, multiplexed single-sided copying, composite single-sided copying, etc., and it is possible to provide versatility. It is.

By the way, the coexistence of double-sided copying and single-sided copying will be explained. First, when normal one-sided copying is required, the front-stage image forming means 18a is not used;
Single-sided copying is performed using only the subsequent image forming means 18b. As a result, the front image forming means 1
8a is not in use, and if double-sided copying becomes necessary, the front-stage image forming means 18 is used in parallel with single-sided copying by the rear-stage image forming means 18b.
Surface copy processing can be performed by a.
The transfer paper 7a on which the front side has been copied is temporarily stored in the transfer paper reversing intermediate tray 24. After the one-sided copying by the subsequent image forming means 18b is completed, the second-side image forming means 18b may perform the reverse side copying. At this time, the transfer paper 7a is fed from the transfer paper reversing intermediate tray 24, and the feeding state is the same as in normal one-sided copying, and there is no need to wait for processing on the front-stage image forming means 18a side, so it can be done in a short time. .

Such processing is also effective during interrupt copying on the double-sided copying side. That is, during interrupt copying (single-sided copying), the trailing edge image forming means 1
8b is used to perform the processing. At this time, the interrupted original is manually fed from the reversing path 37. Then, the front side copying process by the front image forming means 18a is continued, and the transfer paper 7a is stored in the transfer paper reversing intermediate tray 24. After canceling the interruption copy, it is only necessary to restart backside copying of the transfer paper 7a in the transfer paper reversing intermediate tray 24 by the subsequent image forming means 18b.

This also applies when a jam occurs on the side of the subsequent image forming means 18b.
b is stopped, but the front-side copying by the front-stage image forming means 18a is continued, the transfer paper 7a is stored in the transfer paper reversing intermediate tray 24, and after the jam processing, the back-side copying by the rear-stage image forming means 18b is resumed. It is.

Note that in this embodiment, the contact glasses 4a, 4
Although automatic document feeders 13a and 13b are provided on the top of the contact glass 4a and 4b and are connected by a document feed path 21, the document is not provided with an automatic document feeder as seen in ordinary copying machines, and the document is directly transferred to the contact glasses 4a and 4b. It may also be set in the upper position. In this case, the document transport path 21 becomes unnecessary.

Effects As described above, the present invention configures the front and rear image forming means by respectively providing an image recording body, an optical system, and a transfer paper feeding section, and connects them by a transfer paper conveyance path having a transfer paper reversing device. This configuration allows the user to freely select between a mode in which the two-stage image forming means are used in conjunction with each other and a mode in which each stage image forming means is used alone.By selecting the linked use mode, it is possible to perform double-sided copying at high speed with fewer jams, while also making multiple copies possible. It is also possible to apply single-sided copying such as composite copying, providing greater versatility. On the other hand, by selecting the single-use mode, there are two copying machines, which increases the processing capacity of normal single-sided copying. can be performed at high speed,
In a mode in which the front-stage image forming means and the rear-stage image forming means are used independently, even if the rear stage is jammed, the front stage can be operated, which is efficient, and the conveyance path can be shortened. Accordingly, the occurrence of jams is reduced, and the transfer paper conveying device has a transfer paper reversing device including a transfer paper reversing intermediate tray that can temporarily store the transfer paper in an inverted state and re-feed the paper between the image forming means. By connecting the paper by the path, when a jam occurs on the rear image recording member side in the double-sided image forming means linked use mode, the copying operation by the former image recording member side is continued and the transfer paper on which the front side has been copied is turned over and transferred to the intermediate tray. After storage and jam processing, the transfer paper can be re-fed and conveyed from this transfer paper reversal intermediate tray, and the back side copying operation on the subsequent image recording body side can be resumed.

[Brief explanation of the drawing]

The drawing is a schematic side view showing an embodiment of the present invention. 1a to 1b...photosensitive drum (image recording body),
5a-5b...optical system, 7a-7b...transfer paper,
8a to 8b...Transfer paper feeding section, 18a...Previous stage image forming means, 18b...Later stage image forming means, 20
...Transfer paper conveyance path, 22...Transfer paper reversing device.

Claims (1)

[Scope of Claims] 1. An image recording medium, an optical system, a transfer paper feeding section, and an automatic document feeder are respectively provided to constitute a front-stage image forming means and a rear-stage image forming means, and between these image forming means. are combined by a transfer paper conveyance path having a transfer paper reversing device and a transfer paper reversing intermediate tray, and the front and rear image forming means are operated in conjunction with the transfer paper fed from the front transfer paper feeding section to perform this transfer. Based on a mode in which both image forming means are used in conjunction with each other using a transfer paper conveyance path to perform double-sided copying on paper, and a single-sided copy mode setting, the preceding image forming means uses the transfer paper reversing intermediate tray as a paper output tray to output each transfer paper. A double-sided copying machine characterized in that a mode in which each image forming means is used alone without using a transfer paper transport path is selectably set, in which a single-sided copying operation is performed individually on transfer paper fed from a paper feed section. 2. An image recording body, an optical system, and a transfer paper feeding section are provided respectively to constitute a front-stage image forming means and a rear-stage image forming means, and at least a transfer paper is temporarily stored in an inverted state between these image forming means. A transfer paper conveying path having a transfer paper reversing device including a transfer paper reversing intermediate tray that can refeed and transport the paper by refeeding the transfer paper, There is a mode in which both image forming means are used in conjunction with each other to perform double-sided copying on this transfer paper using a transfer paper conveyance path, and a mode in which both image forming means are used in conjunction with each other to perform double-sided copying etc. on this transfer paper. On the other hand, a mode in which each image forming means is used individually without using a transfer paper conveyance path and a mode in which each image forming means is individually used for single-sided copying can be freely set. Continuing the copying operation on the image recording body side, the transfer paper whose front side has been copied is temporarily stored in the transfer paper reversing intermediate tray, and after jam processing, the transfer paper is re-fed and conveyed from this transfer paper reversing intermediate tray to record the subsequent image. A double-sided copying machine characterized by restarting the back-side copying operation using the body side.