JPS6010618B2 - Double-sided copying method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a double-sided copying method for forming images on both the front and back sides of transfer paper, and particularly to a double-sided copying method for obtaining a double-sided copy from a double-sided sheet original using a sheet original conveying device. It is related to.

Generally, in a double-sided copying device, a toner image is formed on the first side of a transfer sheet by placing a document on a document platen and exposing it to light. It is known that in the case of a reverse or one-sided original, another original is placed on the original recording table and exposed in the same way to form a toner image on the second side of the transfer paper to perform double-sided copying. There is.

By the way, the types of manuscripts include relatively thick books such as books with images formed on the front and back sides of a single sheet of paper, double-sided manuscripts in the form of individual sheets, and manuscripts with images only on one side of the sheet. There are various types of originals, such as so-called single-sided sheet originals, which do not have a single-sided sheet.

The most suitable copying method can be considered for each type of document. Recently, there has been a strong demand for so-called high-speed copying, which allows a large amount of copying to be completed in a short period of time, and among the above-mentioned originals, sheet originals in particular are processed and handled in a different way from thick originals, greatly improving the copying speed. This has been attracting attention.

That is, thick originals are placed on a fixed or reciprocating original stacking table, while sheet originals are copied by passing through a sheet conveying device exclusively for sheet originals, so that the copy processing unit for sheet originals is Some proposals have been made to simplify and improve copying speed.

For example, a double-sided copying apparatus as shown in FIG. 1 has been proposed. In FIG. 1, reference numeral 1 indicates a document loading table, 2 a sheet document conveying device, and 3 a slit exposure optical system. The original placed on the original stacking table 1 is 1:
Exposure is performed by a slit exposure optical system 3 consisting of two movable reflecting mirrors 4 and 5 that move at a speed ratio of 1/2. On the other hand, when a sheet original is in the sheet original copy mode, the original table provided at the top of the copying machine that supports the sheet original transport device 2 moves a predetermined distance to the left to become ready for copying, and the sheet original transport device 2 transported. Exposure is performed during transportation. On the other hand, the transfer paper is fed from a cassette 6, a toner image is formed on the surface of the transfer paper by transfer, and is fixed by a fixing device 7, and a direction changing device 8 directs the transfer paper from the rear end to the path 9. The paper is then guided to the photoreceptor drum and sent out again by the next paper feeding command.

Another toner image is then formed on the back side of the transfer paper, completing double-sided copying. However, such a copying apparatus has the following drawbacks. That is, firstly, when the sheet original is a double-sided original, it is impossible to automatically copy the same image relationship as the sheet original on both the front and back sides of the transfer paper at the same time. Second, even if the sheets are divided into two copying cycles and time is spent for copying, the order of the sheet originals will change before and after copying, which is inconvenient for the subsequent processing section. Thirdly, even if you try to perform high-speed copying using a sheet document transport device exclusively for sheet documents,
Unless the transfer paper is processed so that it can follow the processing speed of the sheet original, sufficient results cannot be expected. The present invention is intended to solve the above-mentioned drawbacks, and is particularly designed to copy the same image relationship as that of the sheet original from a double-sided sheet original onto both the front and back sides of transfer paper, and to eject the sheet original and the transfer paper in order. The purpose of this invention is to provide a double-sided copying method that allows for easy duplex copying.

Hereinafter, implementation of the present invention will be explained using the drawings.

FIG. 2 is a schematic diagram of a double-sided copying apparatus showing an embodiment of the present invention.

Reference numeral 11 designates a photosensitive drum, and around it are a charging device 12, a developing device 13, a transfer device 14, a separating device 15, a charge eliminating charger 16, a cleaning device 17,
A static elimination lamp 18 is provided. A fixed manuscript base 19 made of a glass plate is disposed on the upper part of the main body of the copying apparatus, and a slit exposure optical system provided between the manuscript base 19 and the photosensitive drum 11 is installed. The original on the original document stacking table 19 is exposed and scanned. The slit exposure optical system 20 is provided directly below the original pupil table 19,
The manuscript table 19 is moved in the direction of the arrow at the same speed as the photoreceptor drum 11.
a scanning lamp 21 that moves in parallel with the scanning lamp 21;
A lens 22 that moves in the same direction at half the speed of
It is composed of. A sheet document conveying device 25 is provided above the document platform 19 so as to be detachable or pivotable.

The sheet document conveyance device 25 is composed of a paper feed cassette 26, a conveyance belt 27, an intermediate paper feed cassette 28, a switching device 29, and a paper tray 30. On the other hand, the transfer paper conveyance device includes a paper feed cassette 31, a registration roller 32, a fixing roller 33, a switching device 34, and an intermediate paper feed cassette 35.
, and a paper discharge tray 36.

Now, the case of obtaining a double-sided copy from a double-sided sheet original will be explained.

Double-sided sheet originals arranged in order of distribution are stacked in a paper feed cassette 26 with the first page facing downward.

The highest sheet original is fed from the paper feed cassette 26, but if we assume that a double-sided copy is obtained from two sheet originals ○, 02, sheet original 02 is fed first, and then the original The sheet original 02 is conveyed on the table 19 by the conveyor belt 27 and stopped at a predetermined exposure position with the third page facing downward. The arrival of the sheet original P2 at the exposure position is detected directly or indirectly with an appropriate hand, and the sheet original 02 is exposed and scanned by the slit exposure optical system 20. A static latent image corresponding to the image of the third page is formed on the photosensitive drum 11. After the static exposure latent image on the photosensitive drum 11 is visualized by the developing device, the transfer paper P. is fed in synchronization with the movement of the photoreceptor drum 11, an image corresponding to the third page of document ○2 is transferred onto the first side of the transfer paper P, and then passed through the fixing roller 33 to the intermediate The sheets are stacked in the paper feed cassette 35 with the first side facing upward. The switching device 34 connects the intermediate paper feed cassettes 28, 3
1 and the paper discharge trays 30 and 36, and is placed at the position shown by the solid line in the figure. On the other hand, after the exposure is completed, the sheet original P2 is conveyed again and placed on the third intermediate paper feed cassette 28.
The page is ejected with the page facing up. At this time, the paper feed roller 37 provided together with the intermediate cassette 28
It is necessary to retract the separation claw (not shown) so that it does not interfere with the stacked sheet documents. When the sheet original P2 finishes its exposure and starts to be ejected, the next sheet original P2 starts to be ejected. is fed from the paper feed cassette 26.
Thereafter, by performing the same operation, the first
An image is formed that corresponds to the image of the page. Transfer paper P2 is fed from the paper feed cassette 31 in response to the exposure of sheet original P, and an image corresponding to the first page of sheet original 0 is formed on the first side, with the first side facing upward. The paper is sent in an inverted state to the intermediate feeding set 35, and stacked on the first transfer paper P. On the other hand, the sheet original ○ is also sent to the intermediate paper feed cassette 28 in the same way as the sheet original 02, and is reloaded on top of the sheet original 02 with the first page facing upward. When the remaining amount detecting means or a preset counter detects that the sheet document in the paper feed cassette 26 is empty, the operation is then switched to feeding the sheet document from the intermediate paper feed cassette 28. In conjunction with this switching operation, the switching devices 29 and 34 are displaced from the solid line position to the dotted line position, and the full paper roller 38 provided in the intermediate paper feed cassette 35 is moved to the operating position. Paper feed roller 37
Accordingly, the uppermost sheet document ○ in the intermediate paper feed cassette 28 is fed. The fed sheet document P is placed on the document stacking table 1 with the first page facing up and the second page facing down.
placed on top of 9. Similarly, the transfer paper P2 is fed, an image corresponding to the first page of the sheet original ○, is formed on the second side of the transfer paper P2, and while passing through the fixing roller 33, it is once reversed and the paper is ejected. The first page is discharged onto the tray 36 with the first page facing down. On the other hand, after exposure, the sheet original ○ is also stacked on the scarlet paper tray 30 with the first page facing down. Thereafter, similar operations are repeated to form an image corresponding to the fourth page of the sheet original on the back side of the transfer paper P, and the transfer paper P is stacked on the paper tray 36 with this side facing upward. On the other hand, after the exposure, the sheet original P2 is also stacked on top of the sheet original ◯ with the third page facing down. After a predetermined period of time has elapsed since it was detected that the sheet original in the intermediate paper feed cassette is gone, or after the last sheet original is detected by the detection means provided immediately before the paper ejection tray 30, a series of copying operations is performed. is completed.

The sheet originals are arranged in page order on the copy output tray 30 with the first page facing down, while the transfer papers are also arranged in page order with the side on which the image corresponding to the first page is facing down. It's loaded.

It should be noted here that the conveyance of the sheet document involves horizontal feeding and rubbing. For example, when a double-sided copy is made by feeding an A4 size document in the longitudinal direction, that is, vertically, the image is upside down on the front and back sides of the transfer paper, which is undesirable. Next, we will explain the case where a large number of double-sided copies are obtained from a double-sided sheet original. When the sheet original is placed on the original copy stand 19, exposure is performed a predetermined number of times by the slit exposure optical system, and the transfer paper Also, the same image is transferred onto a predetermined number of transfer sheets and stacked in an intermediate paper feed cassette.

If such operations are performed in accordance with the above-mentioned double-sided copying operation, a large number of double-sided copies can be obtained. Next, to explain the case of obtaining a double-sided copy from a single-sided sheet original, the single-sided sheet original is stored in the paper feed cassette 26 or the intermediate paper feed cassette 28.
The originals are stacked face down on the paper, and the paper is fed one by one in the reverse order of the pages.

Since this is a double-sided copying format in which the first page original and the second page original are formed on the front and back sides of transfer paper, the transfer paper is fed from the paper feed cassette 31 and the final page original is placed on the first side. A corresponding image is formed and stocked in the intermediate paper feed cassette 35. When the next sheet of original is placed at the exposure position and exposed, a transfer sheet is fed from the intermediate paper feed cassette 35, an image of the original is formed on the back side, and the sheet is ejected to the paper ejection tray 36. Thereafter, this operation is repeated, and the sheet manuscripts are stacked on the paper tray 30 in page order with the first page facing upward, and the transfer paper is also stacked on the paper output tray 36 in the order of pages with the first page facing upward. There is. Next, we will explain the case of normal copying from a single-sided sheet original.
9 and 34 have both moved to the dotsousen position, and the sheet originals are stacked in the paper feed cassette 26 or the intermediate paper feed cassette 28 with the image surface facing downward, and one sheet original from the highest
Feed paper one by one.

The transfer paper is also fed in accordance with the feeding of the sheet original, and after passing through the fixing low-fu 33, it is directly ejected to the paper ejection tray 36 with the image side facing upward. In this copying mode, if transfer paper of different sizes is prepared and placed in the intermediate paper feed cassette 35 and the paper feed cassette 31 in advance, the size of the sheet original can be detected by an appropriate means and the paper that matches the size can be detected. The transfer paper can be supplied from a cassette containing the transfer paper. Furthermore, if you know in advance that you will be making a large number of copies from originals of the same size, you can store transfer paper of the same size in the paper feed cassette 31 and the intermediate paper feed cassette 35, and use one of the transfer paper. Even if it disappears,
By changing the paper feed selection of the cassette, there is an advantage that copying can be continued without stopping the copying operation. In FIG. 2, if the sheet document conveying device 25 is retracted from the bran document stacking table 19, thick documents can be copied in the same manner.

By the way, in the case of a sheet original, copying efficiency can be further improved by exposing the sheet original while it is moving without stopping.

Therefore, the slit exposure optical system 20 is fixed within or outside the slit exposure scanning range to form an exposure slit, and exposure is performed while the sheet document is being conveyed by the conveyance belt 27. When the optical system 20 is fixed outside the scanning range, it is necessary to newly form an exposure slit exclusively for sheet documents. As explained above, according to the present invention, it is possible to completely automatically obtain a double-sided copy from a double-sided sheet original, and since the sheet original and the transfer paper are each conveyed in the same way, The order of contribution of the sheet original does not change between before and after copying.

Furthermore, when obtaining a double-sided copy from a double-sided sheet original, the first
The 3rd page and odd numbered pages are first copied in succession, and then the 2nd, 4th and even numbered pages are copied, so the time required for refeeding after reversing the transfer paper and sheet original is Since time can be ignored, high-speed double-sided copying can be performed.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a conventional double-sided copying apparatus, and FIG. 2 is a schematic configuration diagram of a double-sided copying apparatus showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 11... Photosensitive drum, 20... Slit exposure optical system, 25... Sheet document conveyance device, 26, 31...
Paper feed cassette, 27... Conveyor belt, 28, 35...
- Intermediate paper feed cassette, 29, 34... switching device, 30
, 36...8E paper tray o precision 1 scheme 2 diagram

Claims (1)

[Claims] 1. In a device that obtains a double-sided copy from a double-sided sheet original, each of the transporting devices for the original and the transfer paper includes a paper feeding means,
An intermediate paper feeding means, a paper ejection means, a separation means provided on the paper feeding means, and a separation means provided on the intermediate paper feeding means for feeding out the originals and transfer paper stacked and stored in the intermediate paper feeding means one by one. a means for separating and feeding out the sheet in a state in which the sheet is moved, and a means for selectively switching the moving direction of the sheet, which is disposed in front of the intermediate sheet feeding means and the sheet discharging means in the sheet moving direction; The sheet is reversed from the paper means through the processing section and conveyed to the intermediate sheet feeding means, and then the sheet that passes through the processing section from the intermediate sheet feeding means is further reversed and conveyed to the sheet discharging means. A double-sided copying method characterized by: