JPS6193460A - Copying device - Google Patents

Abstract

PURPOSE:To form images on both front and rear of transfer paper with the least possible copying processes by exposing plural sheets of originals on an original platen by one time of exposure scanning. CONSTITUTION:The electrostatic latent images of the 10th page and 11th page placed on the side A and said B of the original platen 9 are formed on the photosensitive drum 16 by scanning with reflection mirrors 11, 12. The transfer paper P1, P2 are continuously supplied by the 1st sheet feeder 18. The image of the 10th page of the original is formed on the 1st side of the precedent transfer paper P1 by a transfer device 21 and the image on the 11th page is formed on the 1st side of the succeeding transfer paper P2. The paper P2 is discharged to a discharge tray 25 by a change-over guide 24 installed in the dotted line position and the paper P2 with the 1st side faced upward is imposed on the 2nd sheet feeder 27. The 12th page is placed on the side A and the 13th page on the side B and the electrostatic latent image is formed on the drum 16 by executing exposure scanning. On the other hand, the fresh paper P3 is fed from the feeder 18 when the paper P2 is fed and passes by a switch SW2.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic copying apparatus that forms images on both the front and back sides of transfer paper.

In a conventional double-sided copying apparatus 1, as shown in FIG. A light image of the original is projected to form an electrostatic latent image, which is then visualized by the developing bag W14, and transferred to the first side of transfer paper fed from the paper feeder i15, and transferred to the fixing device. After fixing on the transfer paper in step 6, the transfer paper was loaded with the first side facing upward in the intermediate paper feeder [7].Next, a new document was placed on the document a and placed on the document table L and exposed again to the exposure optical system. The image is similarly formed on the photoreceptor drum 3 by scanning by the system 2, and the transfer paper is fed from the intermediate paper feeder 7 so that its second surface is in contact with the photoreceptor drum 3, and the toner image is placed thereon. After being transferred, the paper is discharged via the fixing device 6 onto 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 one double-sided image.

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.

Moreover, in the above-mentioned apparatus, in the transport path of the transfer paper that has been copied on one side, there is a case where the transfer paper is introduced into the intermediate paper feeder 7, and there is a case where the transfer paper that has been copied on both sides is introduced into the paper output tray 8. Since it can be switched with
If the transfer paper that is continuously conveyed is close to each other,
There was also a risk that the switching member would not be able to switch the conveyance path in time. Here, one copy process means that an electrostatic latent image is formed on the photoreceptor drum by one exposure, and this is converted into a visible image. The toner image is converted into a toner image and transferred onto a sheet of transfer paper, the toner image on the transfer paper is fixed, and the toner image is discharged.

By the way, recently there has been a growing demand for copying to be completed in a short period of time, and for this reason high-speed copying devices have been actively developed6. However, one thing that is not fully satisfactory in the field of double-sided copying is that nothing has been developed that is fully satisfactory. This is the current situation.

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

Another object of the present invention is to provide a high-speed copying apparatus that can form images 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 novel 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.

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 the copying apparatus 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 system 10 includes a first reflecting mirror 11, a second reflecting mirror 12, which move in the same direction parallel to the original table 9 at a speed ratio of 1:1/2 in the direction of the arrow shown in the figure, and a fixed in-mirror lens 13. It is composed of a third reflecting mirror 14. A book is placed on the manuscript table 9 in an open state. For convenience, place the even numbered pages of the book on the manuscript table 9.
The right half of the page is A, and the odd pages are set to be the left half of the page B. FIG. 3 shows a plan view of the document mounting table 9 shown in FIG. 2. As shown in 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 table 9 is used as shown in FIG.
based on.

In addition to the above-mentioned method, the book can also be placed with reference to the center line 9c 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 input to the control device of the copying machine.

This silkworm code causes the copying device to switch each copying element from a single copying mode to a double-sided copying 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 111 and the second reflecting mirror 12 move in the direction of the arrow and scan without stopping until they reach the position shown by the dashed line, thereby exposing the surface A of the original table 9. , the original images of pages 10 and 11 placed on side B 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 brush development, for example. First and second reflecting mirrors 11.1 after exposure scanning has been completed
2 returns to the original position. On the other hand, the first sheet feeding device 1
A4 size transfer paper is stored in B, and the control device controls the rotation of the paper feed roller 19° and the registration roller 20 to feed the first sheet feeding device i! Two sheets of transfer paper are successively supplied from 18 at a predetermined interval from each other.

That is, as shown in FIG. 5, the transfer sheets PL and P2 are conveyed in the direction of the arrow, and the transfer sheet P2 is fed and conveyed while being supported at a distance t from the transfer sheet PI.

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 a transfer position and come into close contact with the photosensitive drum 16, and the visibly purified 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 PI, 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 is completed, the toner image is fixed on it by the heat fixing roller device 22, and the static electricity is removed by the static eliminator 23. After that, the preceding transfer paper P1 is ejected by the switching guide 24, which is initially located at the dotted line position. The sheet is conveyed toward the tray 25, and is ejected while being pinched by the sheet ejection roller 26, which rotates at a higher speed than the other conveyance rollers. Paper ejection roller 26 at high speed
is rotating, the distance t between the transfer paper P1 and the following transfer paper P2 is widened, and the transfer paper P2 is switched to the guide 2.
4 facilitates feeding into the second sheet feeder @27.

That is, if the switch Sv1 detects that the leading edge of the transfer paper PL has passed the switching guide 24 and immediately moves it to the solid line position, the direction can be changed even if the following transfer paper P2 is conveyed at a relatively narrow interval. becomes easier. The transfer paper P2 is loaded onto the second sheet 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 first?゛The sheet feeding device 27 can also be retracted.

Next, turn over page 11 of the book and put page 12 on side A.

The 13th page is placed on the B side, 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 sheet supply 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 first side of the book on its second side (back side).
The corresponding image is on page 2.

An image corresponding to page 13 of the book is formed on the first side (front side) of the transfer paper P3, and after passing through the fixing device [22], the preceding transfer paper P2 is placed on the paper output tray 25 with the first side facing downward. loaded. The subsequent transfer paper P3 is placed in the second position with the first side facing upward.
The sheets are stacked on the sheet feeding device 27.

Thereafter, the same copying process is repeated, and after the image of the 15th page of S registration is formed on the first side of the transfer paper P4, which is the last copy, this is not conveyed to the second sheet feeding device 27.
The paper is ejected to the paper ejection tray 25 as it is.

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-to-back relationship as the book and in page order. That is, the 11th and 12th pages are copied on the front and back sides of the transfer paper P2, and the 13th and 14th pages are copied on the front and back sides of the transfer paper P3.

In addition, when copying starts from an odd numbered page of a book in FIG. 4, the first odd numbered page is placed on side A and copied onto one sheet of transfer paper, or it is placed on side B. 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.

By the way, the interval between two successive sheets of transfer paper is such that when a book is placed on the manuscript table 36 as shown in FIG. In general, when copying transfer sheets on which no image is formed is bound in page order, if there is no binding margin, even the image portion will be bound, which is inconvenient. Therefore, as shown in FIG. 6(a), in FIG.
Even if the distance t from 2 is zero, the binding margin may not be sufficient. Therefore, as shown in Fig. 6(b), the central part p
If the preceding transfer paper P1 and the following transfer paper P2 are conveyed while being overlapped by a length of Q so that the portion where no image is formed is used as the binding margin, the above-mentioned transfer papers PL and P2 can each have sufficient space. A binding margin is formed. Furthermore, 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 if the sheets are bound, the images will not be damaged.

FIG. 7 shows a paper feeding device that feeds the two sheets of transfer paper described above in a superimposed manner.

In FIG. 7, 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 39 is held between the transport rollers 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 moving the adjusting means provided outside the machine and the paper detecting means depending on the type of book, size, etc. Alternatively, as a modified example, if the paper feed roller is constantly rotated during one copying process without providing a paper detection means, the transfer paper can be overlapped and fed by the distance from the cassette tip to the paper feed roller. It is also possible to do so. 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 copying apparatus of the present invention, a plurality of originals on the original table are exposed by one exposure scan, and a copy image formed on the photoreceptor by this exposure is
In response to this, after being transferred to the fed transfer paper, the preceding transfer paper on which double-sided copying has been completed can be ejected faster than the following one, so that one single-sided i copy is completed, in other words, the intermediate feed is transferred again. Switching the conveyance path of the subsequent transfer paper used for transfer from the paper section.

This can be easily carried out even if the transfer sheets are conveyed at relatively narrow intervals.

Therefore, different images are formed on two sheets of transfer paper in one copying process. In this case, it is possible to shorten the time required for the process of transferring to a subsequent transfer paper among consecutive transfer papers, and also to omit one process.

Furthermore, when the time required for such a copying process is shortened, it is possible to reliably switch between the preceding and succeeding conveyance paths, thereby preventing troubles in the copying process. Furthermore, the images are formed on the transfer paper after copying in the same page order as the original, which is extremely 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, for double-sided sheet originals, high-speed duplex copying is possible using a sheet original transport device.

Similar to transfer paper, the page order of sheet originals does not change at all before and after copying, making subsequent processing convenient.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of a conventional double-sided copying machine, FIG. 2 is a schematic diagram of a double-sided copying machine showing an embodiment of the present invention, and FIGS. 3 and 4 are diagrams for explaining processing of originals. , FIG. 5 is a diagram for explaining the transfer paper conveying method of the present invention,
6(a) and 6(b) are diagrams for explaining a method of transporting transfer paper in book copying, and FIG. 7 is a sectional view of a sheet feeding device showing another embodiment of the present invention. be. 9.36... Document placement table, 10... Exposure optical system, 16... Photosensitive drum, 18... First sheet feeding device. 25, 32... Paper discharge tray, 27... Second sheet feeding device, 29... Sheet original conveying device, pl
, p2...transfer paper, S...sheet manuscript. Invitation 6 Figure (b) L Flame 7 Figure

Claims (1)

[Scope of Claims] A document placing table on which two originals can be placed; an exposure scanning means for exposing the two originals on the document placing table by reciprocating once without stopping; means for continuously feeding a number of transfer sheets corresponding to the two originals on the document table when the exposure scanning means moves to a predetermined position; and means for transferring the images formed by the exposure scanning means. a conveyance path switching means for guiding the subsequent one-sided copyed transfer paper of the two sheets of transfer paper conveyed in the conveyance path of the transferred transfer paper to an intermediate supply section that temporarily stores the transfer paper; a sheet discharging means located at a speed higher than the conveying speed of the transfer paper conveying means located in front of the conveyance path switching means in order to widen the interval between the two sheets of transfer paper; A copying apparatus comprising: a detection means that is arranged at a position where it can detect a double-sided copied preceding transfer sheet discharged by the means, and controls the conveyance path switching means.