JPS6017456A - Both side copying device - Google Patents

Abstract

PURPOSE:To enable both side copying at high speed and omission of one cycle of copying process, too by forming each of two different images on each of two transfer sheets in one cycle of the copying process. CONSTITUTION:A copying machine employing a both side copying method is provided with an original platen 9, and an optical exposure system 10 composed of the first and second reflective mirrors 11, 12 each moving in the same arrow direction in parallel to the platen 9 at a speed ratio of 1:1/2, a fixed in-mirror lens 13, and the third reflection mirror 14. A book is placed on the platen 9 in an opened state, and e.g., an even-numbered page is placed on the right-half of the platen 9 and an odd-numbered page is placed on the left half. Both sides of the pages can be copied at the same time by applying a program for copying both sides to a controller.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a double-sided copying device for forming images on both the front and back sides of transfer paper for an electrophotographic copying device.

Conventionally, in a double-sided copying method, as shown in FIG. An electrostatic latent image is formed by projecting a light image of the original document, and then this is visualized by a developing device 4, and the image is transferred to the first side of a transfer sheet fed from a paper feeding device 5, After the toner is fixed on the transfer paper by the fixing device 6, the transfer paper is loaded onto the intermediate paper feeder 7 with its first side facing upward. Next, a new original is placed on the original document mounting table 1 and scanned again by the exposure optical system 2 to similarly form an image on the photosensitive drum 3, and the transfer paper is transferred from the intermediate paper feeder 7 to its second side. The paper is fed so as to come into contact with the photoreceptor drum 3, the toner image is transferred thereon, and then the paper is discharged via the fixing device 6 to the paper discharge tray 8 with the second side facing upward. Through the above operations, double-sided copying is performed in which images are formed on both the front and back sides of the transfer paper. That is, two copying processes were required to copy both sides.

Further, even in an automatic duplex copying apparatus having a conveyance device exclusively for sheet originals, two copying processes are required to form different images on both the front and back sides of the transfer paper, as in the case described above.

Here, one copying process means that an electrostatic latent image is formed on a photoreceptor drum by one exposure, and this is visualized and transferred onto a sheet of transfer paper, and a toner image is formed on the transfer paper. This refers to the copying process from fixing the image to ejecting it.

Incidentally, recently there has been a growing demand for completing copying in a short time, and for this reason high-speed copying apparatuses have been actively developed. However, in the field of double-sided copying, the current situation is that nothing fully satisfactory has been developed.

In view of these points, it is an object of the present invention to provide a novel high-speed double-sided copying apparatus.

Another object of the present invention is to provide a high-speed double-sided copying apparatus that allows images to be formed on both the front and back sides of transfer paper with as few copying processes as possible.

Still another object of the present invention is to provide a new double-sided copying apparatus that forms images on both the front and back sides of transfer paper in exactly the same front-back relationship as the original.

Still another object of the present invention is to provide a double-sided copying apparatus that can provide a binding margin on two successively conveyed transfer sheets when continuously copying a document in book mode, such as a book.

Embodiments of the present invention will be described below with reference to the drawings.

First, a case of double-sided copying of a book manuscript such as a book will be explained.

FIG. 2 is a schematic diagram of a double-sided copying apparatus applied to the double-sided copying method of the present invention. In FIG. 2, reference numeral 9 indicates an original placing table, and reference numeral 10 indicates an exposure optical system. The exposure optical systems 10 are arranged in the same direction and parallel to the original table 9.
a first reflecting mirror 11 that moves in the direction of the arrow shown in the figure at a speed ratio of L;
The second reflecting mirror 12, the fixed in-mirror lens 13, and the third
It is composed of a reflecting mirror 14. A book is placed on the manuscript table 9 in an open state. For convenience, the even-numbered pages of the book are placed on the right half A of the manuscript table 9, and the odd-numbered pages are placed on the left half B.
Set it so that Figure 3 shows the document mounting table 9 in Figure 2.
FIG. As for a book, as shown in FIG. 4, the even-numbered page 10 of the book is placed on side A, and the odd-numbered page 11 is placed on side B. Next, a case will be explained in which double-sided copying of pages 10 to 15 of a book is performed. If the book is A4 size, the entire surface of the document placement table 9 is used as shown in FIG. put it on. In addition to the above-mentioned method, the book can also be placed with reference to the center line 9G of the document table 9. In the embodiment of the present invention, books are placed according to the former criterion.

Now, a program for making double-sided copies of an A4 size book is manually input to the control device of the copying machine.

This input signal causes the reproduction machine to switch each copy element from a single copy mode to a double-sided copy mode. After a predetermined period of time has elapsed, a message indicating that copying may be started is displayed. The copying operation starts when the operator places the book at a predetermined position on the document table 9 and closes the print switch. The exposure lamp (not shown) is turned on, and the first reflecting mirror 11 and the second reflecting mirror 12 move in the direction of the arrow and scan to the position shown by the dashed line, and then scan to the A side and the B side of the document mounting table 9. first placed
The original images of pages 0 and 11 are projected onto a photosensitive drum 16 that is uniformly charged by a charging device 15 to form an electrostatic latent image. This electrostatic latent image is visualized by a developing device 17 that performs magnetic plan development, for example.

First and second reflecting mirrors after exposure scanning 1.1.1.2
returns to its original position. On the other hand, the first sheet feeding device 18
A4 size transfer paper is stored in the , and the control device controls the rotation of the paper feed roller 19 and the registration roller 20 to feed the two transfer papers from the first sheet supply device 18 at a predetermined distance from each other. supply continuously. That is, as shown in FIG. 5, the transfer sheets PI and B2 are conveyed in the direction of the arrow, and the transfer sheet P2 is fed and conveyed while maintaining the distance t from the transfer sheet P1. This interval t can be adjusted by adjusting the interval between the documents placed on the A side and the B side. This interval t will be explained in detail later. The fed transfer papers P1 and 'P2 are conveyed to the transfer position and come into close contact with the photoreceptor drum, and the visualized toner image is electrostatically transferred by a transfer device 21 consisting of a transfer charger. . That is, an image corresponding to the 10th page of the original is formed on the first side of the preceding transfer paper P1, and an image corresponding to the 11th page of the original is formed on the first side of the following transfer paper P2.

After the transfer has been completed, the toner image is fixed on the transfer paper by the heating fixing roller device 22, and the static electricity is removed by the static eliminator 23. After that, the preceding transfer paper P1 is moved to the paper ejection tray by the switching guide 24, which is initially located at the dotted line position. The sheet is conveyed in the direction of 25, and is ejected by being gripped by a discharge roller 26 which rotates at a higher speed than other conveyance rollers. Since the paper ejection roller 26 is rotating at high speed, the transfer paper P1 and the subsequent transfer paper P
2, the larger the distance between the transfer paper P2 and the transfer paper P2 is, the larger the gap between the transfer paper P2 and the transfer paper P2 is. That is, the leading edge of the transfer paper P1 is the switching guide 24.
After the switch SWI detects that the
If it is immediately displaced to the solid line position, the direction can be easily changed even if the subsequent transfer paper P2 is being conveyed at a relatively narrow interval.

The transfer paper P2 is stacked on the 27th=1 supply device 27 with the first side facing upward. At this time, the paper feed roller 28 needs to be retracted to a position where it does not interfere with proper stacking of the transfer paper P2. Or the second note supply device 27
It is also possible to evacuate the person.

Next, turn over page 11 of the book, put page 12 on side A, and put page 12 on side B.
The 13th page is placed on the surface, and exposure scanning is performed again to form electrostatic latent images corresponding to the images of the 12th and 13th pages on the photosensitive drum 16. On the other hand, the transfer paper P2 is fed by the paper feed roller 28 from the second sorting and feeding device 27, and is conveyed to the transfer position by the registration roller 20 in synchronization with the movement of the photosensitive drum 16. At the same time as the transfer paper P2 passes through the switch SW2, a new transfer paper P3 is fed from the first sheet supply device 18, and is continuously conveyed while maintaining the interval t from the preceding transfer paper P2. The transfer paper P2 that has passed through the transfer device 21 has the 12th page of the book on its second side (back side).
An image corresponding to page 13 of the book is formed on the first side (front surface) of the transfer paper P3, and after passing through the fixing device 22, the preceding transfer paper P2 is transferred with the first side facing downward. The paper is stacked on the paper discharge tray 25. The subsequent transfer paper P3 is stacked on the second sheet supply device 27 with the first side facing upward. Thereafter, the same copying process is repeated, and after the image of the 15th page of the book is formed on the first side of the transfer paper P4, which is the last copy, the image is not conveyed to the second sheet feeding device 27. It is discharged to the IT paper discharge tray 25. After the above-described copying is completed, the transfer sheets P1 to P4 are stacked on the paper discharge tray 25, having been copied in exactly the same front and back relationship as the book and in page order. That is, the 11th page and the 1st page are printed on the front and back sides of the transfer paper P2.
Page 2 is copied, and pages 13 and 14 are copied on the front and back sides of the transfer paper P3, respectively.

In addition, when copying starts from an odd numbered page of a book in FIG. The process may be performed at a paper feeding timing that conveys only the succeeding transfer paper in the absence of the preceding transfer paper.

Next, the case of double-sided copying of a double-sided sheet original will be described. FIG. 6 shows a partial sectional view of a double-sided copying apparatus having a sheet document conveying device.

The sheet document transport device 29 includes a sort document feed device 30,
It is composed of an intermediate sheet feeding device 31 and a sheet discharge tray 32, and is attached above an exposure window 33 formed on the top surface of the copying device. Two double-sided sheet originals 81 are now arranged in page order on the sheet original feeding device 30. A method for double-sided copying of sheet originals will be described in which sheets S2 are stacked with the first page facing downward. Since the photoreceptor drum, the processing devices surrounding it, and the transfer paper conveying device shown in FIG. 2 can be used as they are, they will be described using the reference numerals of the devices shown in FIG.

Double-sided notebook originals are fed from the sheet original feeding device 30 in order from the top by a feeding roller 30α. That is, two sheet originals are 82. The sheets are fed to the exposure window 33 in the order of Sl, and the third
The first page is exposed in this order to form an electrostatic latent image on the photosensitive drum 6. The transfer paper is also fed 2 from the first sheet feeding device 18.
Sheet of transfer paper P2. PL is continuously fed and conveyed at the same interval as the 7-sheet originals S1 and S2, and the image of the third page of the sheet original S2 is displayed on the first side (front surface) of the preceding transfer paper P2. A sheet original S is placed on the first side of the subsequent transfer paper P1.
The images of the first page of P2.1 are formed respectively on the second sheet feeding device 27. They are loaded in the order of PI with the first side facing upward.

On the other hand, the sheet originals SL and S2 after the exposure are also stacked on the intermediate paper feeder 31 by the switching guide 34 in the order of 82 and 81 with the odd-numbered pages facing upward. When the switch SW3 detects that the two sheet originals have been conveyed to the intermediate paper feeder 31, the paper feed roller 35 starts feeding the sheets after a certain period of time, and the sheet originals are sent to the exposure window 33 in the order of S1 and S2 from the top. Feed the paper towards. Electrostatic latent images are formed on the photosensitive drum 16 in the order of the second page and the fourth page. On the other hand, the transfer paper is also fed from the second sorting and feeding device 27 in the order of PL and P2, and the sheet original S is placed on the second side of the preceding transfer paper P1.
The image of the second page of No. 1 is formed on the second side of the subsequent transfer paper P2, and the image of the fourth page of the sheet original S2 is formed on the second side of the subsequent transfer paper P2. They are stacked in page order. For sheet manuscripts, please use SL,,8
2 are stacked on the paper ejection tray 32 with the odd numbered pages facing down. Naturally, the switching guide 34 has been switched to the dotted line position at this time. Although the above description has been made regarding the case of two sheet originals, double-sided copying can be performed in exactly the same way even with three or more sheet originals.

If you still wish to obtain a large number of copies from one original, place the originals arranged in page order on the paper ejection tray 32 directly on the sheet original feeding device 30, and repeat this process for the desired number of copies. Bye. Alternatively, by circulating between the intermediate paper feeder 31, the exposure window 33, the switching guide 34, and the intermediate paper feeder 310 for the desired number of copies, double-sided copying can be performed automatically without manual intervention. . It should be noted that if the sheet originals are stacked on the sheet original feeding device 3o with the odd numbered pages facing upward, the order of the pages will be out of order on the paper ejection tray 32.

By the way, the distance between two sheets of transfer paper that are continuously conveyed is such that, for example, as shown in FIG. Often no image is formed. Generally, when copying transfer paper is arranged in page order and bound, if there is no binding margin, even the image part will be bound, which is inconvenient. Therefore, as shown in FIG. 7(a), in FIG.
Even if the distance t from 2 is set to zero, the binding margin may not be sufficient. Therefore, as shown in Fig. 7<h), the central part λ
If the preceding transfer paper P1 and the following transfer paper P2 are conveyed while being overlapped by a length of 2 so that the portion where no image is formed is used as the binding margin, the above-mentioned transfer papers P1 and P2 can each have sufficient space. A binding margin is formed. Moreover, according to the double-sided copying method of the present invention, the binding margin is formed at the same position on both the front and back sides of the transfer paper, so even when the sheets are bound, the images are not damaged.

FIG. 8 shows a paper feeding device that feeds the two sheets of transfer paper described above in a superimposed manner.

In FIG. 8, the reference numeral 37 indicates a cassette, the reference numeral 38 a paper feed roller, the reference numeral 39 a conveyance roller, and the reference numeral 40 a paper detection means. The conveyance roller 39 is constantly rotating at a speed V, and the paper feed roller 38 is connected to the rotation shaft 3.
8a and an overrunning clutch (not shown)
The transfer paper P1 fed by the paper feed roller 38 is held by the transport roller 39 and transported at a speed V. The paper feed roller 38 transfers the transfer paper P1 to the transport roller 3.
After reaching 9, the drive is cut off, but the overrunning clutch continues to rotate. When the paper detection means 40 detects the leading edge of the transfer paper P1, the paper feed roller 38 is driven to rotate again. Therefore, by appropriately adjusting the distance of the paper detection means 40 from the paper feed roller 38, the overlapping length of the transfer paper can be changed. For example, this can be easily done by interlocking the adjustment means provided outside the machine with the paper detection means depending on the size of the type of book. In addition, as a modified example, only one paper feed roller can be used without providing a paper detection means.
If you keep it rotating all the time during the copying process,
It is also possible to feed the transfer sheets by overlapping them by the distance from the leading edge of the cassette to the paper feeding roller.

At this time, the overlapping length can be adjusted by moving the paper feed roller and the cassette relative to each other.

As explained above, according to the double-sided copying apparatus of the present invention,
When copying two sheets of transfer paper that are successively conveyed from a book original, it is possible to form a binding margin in advance on the transfer paper obtained after copying, so that the transfer paper after copying can be aligned in page order. This prevents the image section from being sometimes stapled. Additionally, different images can be formed on two sheets of transfer paper in a single copying process, making it possible to perform high-speed double-sided copying and eliminating one copying process, which saves power. , which is excellent in improving machine life. Furthermore, the images on the transfer paper after copying are formed in page order and in exactly the same front and back relationship as the original, which is convenient. In particular, even for book manuscripts such as books, double-sided copying with the same front-back relationship can be performed at high speed. On the other hand, in the case of double-sided sheet originals, high-speed duplex copying is possible using a sheet original transport device, and like with transfer paper, the order of the pages does not change at all before and after copying for sorted originals, and subsequent processing is easy. It's convenient.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a conventional double-sided copying apparatus, FIG. 2 is a schematic diagram of a double-sided copying machine to which an embodiment of the present invention is applied, and FIGS. 3 and 4 are diagrams for explaining the processing of originals. 5 is a diagram illustrating the transfer paper transport method in the double-sided copying apparatus shown in FIG. 2, and FIG. 6 is a portion of a double-sided copying machine having a sheet document conveying device showing an embodiment of the present invention. 7(α) and 7(h) are diagrams for explaining the method of transporting transfer paper in book copying, and FIG. 8 is a sectional diagram of a sheet feeding device showing an embodiment of the present invention. It is. 9, 36... Document placement table, 10... Exposure optical system, 16
- Photoreceptor drum, 18... First sheet supply device, 25,
32... Paper discharge tray, 27... Second sheet supply device,
29.Note document feeding device, 30.Sheet document feeding device, 31..Intermediate paper feeding device, 33..Exposure window, PL,
P2...Transfer paper, S...Sheet original. rZ ■7 Flash (tp> maximum 64

Claims (1)

[Scope of Claims] A document placing table for placing a book-shaped document having two document surfaces, and an optical scanning means for exposing and scanning the document surface on the document placing table in one scan. , a rotatable photosensitive drum on which an electrostatic latent image corresponding to the document is formed on a photosensitive layer on the surface thereof by the optical scanning means; and a rotatable photosensitive drum arranged along the rotating direction of the photosensitive drum. electrification,
an image forming means comprising a device for development, transfer, and cleaning, and a fixing device for fixing the transferred image; and a first transfer paper supply means for feeding the transfer paper toward the transfer position of the photoreceptor drum. Above, the transfer paper fed from the first transfer paper supply means and on which the image on the photoreceptor drum has been transferred is temporarily stored, and then again;
A second transfer paper supply unit that feeds the transfer paper toward the transfer section of the photoconductor drum, and a transfer paper that is fed to the transfer position of the photoconductor drum by the first and second transfer paper supply units and has completed the final transfer. A paper discharge tray for storing paper and the second transfer paper supply means are arranged upstream in the transfer paper movement direction with respect to the paper discharge tray, and the transfer paper movement direction is controlled by the second transfer paper supply means. a switching means for selectively switching between the means side and the paper discharge tray side, and a transfer paper fed toward the transfer position of the photoreceptor drum by the first transfer paper supply means, and after being transferred, the transfer paper is reversed. a means for conveying the transfer paper toward a second transfer paper supplying means in a state of means for directing the paper in an inverted state toward the paper output tray; and a means for directing two sheets of transfer paper toward the transfer position of the photoreceptor drum in response to one document scanning by the optical scanning means. In a double-sided copying apparatus having a feeding control means for feeding the first transfer paper supply means and/or a second transfer paper, when the documents on the two sides of the document mounting base are book-shaped, the first transfer paper supply means and/or the second transfer paper The feeding start time of the subsequent transfer paper that is continuously fed from the supply means is advanced, and parts of the preceding and following transfer paper are conveyed and transferred in an overlapping state, and that part is used as a binding margin. 2. A double-sided copying apparatus comprising a binding margin setting means for setting a binding margin.2 The feeding control means is configured to cause the feeding control means to continuously supply transfer paper from the first transfer paper supply means during the first scan of the optical scanning means. 3. The double-sided copying apparatus according to claim 1, wherein the duplex copying apparatus is configured to transport one of the transfer sheets toward the paper discharge tray and the other transfer sheet toward the second transfer paper supply means. 3. Feeding During the second scan of the optical scanning means, the control means continuously feeds out one sheet from the first transfer paper supply means and one sheet from the second transfer paper supply means, and after the transfer, the first transfer paper is fed out. The transfer paper from the transfer paper supply means is conveyed to the second transfer paper supply means, and the transfer paper fed out from the second transfer paper supply means and on which images are transferred on both sides is conveyed to the paper discharge tray. A double-sided copying apparatus according to claim 1, which is set to operate as follows.