JPH0481865A - Automatic both-side copying device - Google Patents

Abstract

PURPOSE:To minimize the generation of the waiting time between 1st side copying and 2nd side copying and to improve productivity at the time of both- side copying by generating a detection output without waiting for the completion of stacking by as much as the number of copying set parts in an inversion transfer section. CONSTITUTION:An original 1 imposed on platen glass 2 is exposed by scanning exposing optical system 20 and the latent image corresponding to the original 1 is formed on the surface of a photosensitive body 30. This latent image is made into a toner image on the surface of the photosensitive body 30 by a photosensitive body image forming section 3. The toner image is transferred to copying paper 41 supplied from a paper feed section 40. The transferred toner image is fixed under heating by a fixing device 50. The copying paper with which the copying of the 1st side is completed is introduced to the inversion transfer section 80 by a paper discharge changeover section 70. The copying paper transferred again to the photosensitive body 30 while inverted in this transfer section 80 is subjected to the copying of the 2nd side. After this toner image is fixed, the paper is discharged to the outside of the machine by the changeover section 70.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to improving the productivity of an automatic duplex copying apparatus that reads both sides of a document and copies both sides of copy paper.

(Background of the Invention) There is an automatic reversing document feeder W (hereinafter referred to as RADF) as a device that automatically inverts the document when a double-sided document is set on the Z and copies both sides of the document. Using such a device, large quantities of copies can be easily made. Furthermore, since the copies are in the same order as the original, there is no need to rearrange them after copying.

Furthermore, by linking with a sorter, collation and page sorting can be performed automatically, making it possible to accurately arrange large quantities of copies.

In addition, the ADU is a device that can automatically copy both sides of copy paper (hereinafter referred to as copy paper) with the touch of a button.
There is. By using this function, information from two pages of a document can be combined on one sheet, making it possible to save on copy paper costs and at the same time making filing easier. It can also be used in a variety of ways, such as organizing materials into a booklet format for easy viewing.

By the way, when double-sided copying is performed using a conventional automatic double-sided copying device, it is important to note that the final number of copy sheets (copy sheets on which only one side has been copied) of the set number of copies for first side copying has completed stacking in the ADU. After this was detected, paper refeeding from the ADU was started.

(Invention or problem to be solved) Such an operation will be explained with reference to FIG.

When the copy button of the copier is pressed (Fig. 6(a)),
Copy paper for copying the first side is fed (FIG. 6(b)). In this operation description, it is assumed that a certain number of copies are set (hereinafter, this set number of copies will be referred to as the set number of copies). Here, when the first sheet of copy paper reaches the photoreceptor, copying of the first side is started and is performed for the set number of copies (FIG. 6(C)).

The copy paper on which the first side has been copied in this way is
are stacked in U (FIG. 6(d)).

When stacking in the ADU is completed, paper alignment is performed in the ADU (FIG. 6(e)). After completing this paper alignment, A
Paper is re-fed from the DU (FIG. 6(f)), and the second side is copied (FIG. 6(g)).

According to the above time chart, there is a period during which the photoreceptor is on standby (not operating) from the completion of copying on the first side to the start of copying on the second side. Because of this waiting period for the photoreceptor, it has been difficult to improve productivity during double-sided copying.

Note that the ratio of standby time to copy time varies depending on the set number of copies, but in any case, it hinders the improvement of productivity.

The present invention has been made to solve the above problems, and its purpose is to improve productivity during double-sided copying by shortening the time from the end of copying the first side to the start of copying the second side. The object of the present invention is to realize an automatic double-sided copying apparatus that can perform the following functions.

(Means for Solving the Problems) The present invention, which solves the above-mentioned problems, reverses the copy paper on which the first side has been copied by a reversing transfer unit, and transfers the second side of the copy paper sent out from the reversing transfer unit to An automatic duplex copying apparatus that performs copying includes a paper feeding state detection means for detecting that a set number of copy sheets have been fed from a paper feed section of the main body, and at least one sheet of copy paper stacked in a reversing transfer section. a paper refeeding state detecting means for detecting that paper refeeding is possible; and a paper refeeding state detecting means that receives detection outputs from the paper feeding state detecting means and the paper refeeding state detecting means, and starts refeeding paper to the reverse transfer unit. The invention is characterized by comprising a timing control means for giving an instruction.

(Function) In the automatic duplex and double-sided copying apparatus of the present invention, when it is detected that the copy paper from the main body paper feed section has been fed by the set number of copies, the paper feed state detection means generates a detection output, and the copy paper is reversed. When at least one of the copy sheets stacked in the transfer section can be re-fed, a detection output is generated by the re-feed possible state detection means. Upon receiving these detection outputs, the timing control means gives an instruction to the reversal transfer section to start paper refeeding.

Here, since the detection output is generated without waiting for the stacking of the set number of copies to be completed in the reverse transfer unit, the first side copy and the second
The waiting time between copying and copying can be minimized.

(Example) Examples of the present invention will be described in detail below with reference to the drawings.

First, the general operation of the electrophotographic copying apparatus to which the present invention is applied will be explained with reference to FIG.

In Figure 2, the automatic double-sided document feeder (hereinafter referred to as RAD)
10 (referred to as F) is moved onto the platen glass 2 by RADFlo at the start of copying. The original 1 placed on the platen glass 2 is exposed by the scanning exposure optical system 2o, and a latent image corresponding to the original 1 is formed on the surface of the photoreceptor 3o. This latent image is formed into a toner image on the surface of the photoreceptor 30 by the photoreceptor image forming section 3 . The toner image is transferred to copy paper 41 supplied from a paper feed section 40, which will be described later, and the transferred toner image is heated and fixed by a fixing device 50. The copy paper on which the first side has been copied in this manner is transferred to the reverse transfer section by the paper ejection switching section 70.
(hereinafter referred to as ADU) 80. And this A
The second side of the copy sheet is reversed in the DU 80 and transferred to the photoreceptor 30 again (formation of a toner image).

After this toner image is fixed, the paper is ejected to the outside of the machine by the paper ejection switching section 70.

Next, FIG. 1 shows the electrical configuration of the device of this embodiment, FIG. 2 mentioned above, and FIGS. 3 to 5 show the flow of operation of the device of this embodiment.
The operating state of this embodiment will be explained step by step along the copy paper feeding process with reference to the figures.

First, settings such as the number of copies, copy paper size, variable magnification, and final ejection position are made from an operation setting section (not shown) (step 2).

An original is set in RADF 1, 0, and copying starts when the copy button is pressed.

As described above, copy paper 41 is supplied to the photoreceptor 30 from the copy paper feed section 40 (step 2).

The copy paper feed section 40 is provided with three paper feed cassettes 42a to 42c that accommodate, for example, three types of copy paper 418 to 41C of different sizes.

The copy papers 41a to 41c are stored in paper feed cassettes 42a to 42C.
From the feed rollers 43a to 43c and the feed belts 44a to 4
4c. Delivery rollers 43a to 43
Delivery belts 44a to 44C are stretched on c.
These delivery belts 44a to 44c are the copy sheets 41a to 4]C
By rotating the delivery rollers 43a to 43c clockwise (FIG. 2) while in contact with the uppermost layer of copy paper 41,
A to 41C are sent out one by one to the left in FIG.

Copy paper 41a sent out by sending belts 44a to 44c
~41. C is conveyed to position P2 (FIG. 2) by paper feed roller 61 and registration roller 62. From position P2, the toner image is sent out by registration rollers 62 after being synchronized with the rotation of photoreceptor 30, and a toner image is transferred from the surface of photoreceptor 30 (first side copying, step (2)).

In the case of single-sided copying, the image is then heated and fixed in a fixing device 50,
Copying is completed when the paper is ejected from the paper ejection switching section 70 to the outside of the machine.

In the case of double-sided copying, the copy sheets stacked in the ADU 80 are re-fed (step 2) as described below.

Downstream of the fixing device 50, there is a paper ejection path which has a function of switching between a paper ejection path 76 in which the copy paper 41 after fixing is advanced straight and ejected to the outside of the machine, and an introduction path 77 in which the copy paper 41 is transported to the guide plate 71 for double-sided copying. A switching section 70 is provided. Paper ejection switching section 7
0 is the guide plate 7].

Upstream roller 72. Downstream roller 73. It is comprised of a movable branch body 75 having an inverted triangular cross section that swings about a shaft 74, an electromagnetic solenoid (not shown), and the like. A movable branch 75 having an inverted triangular cross section provides a paper discharge path 76 along the upper surface of the movable branch 75 and a guide plate 71 along the lower right side.
An introduction path 77 that communicates with the guide plate 7 along the lower left side surface.
1 and downstream rollers 73 are respectively formed.

The movable branch body 75 is driven by a drive device (not shown) such as an electromagnetic solenoid, so that the right tip moves up and down, and the introduction path 7
7 and close the paper ejection path 76, or conversely, open the paper introduction path 77.
It changes depending on whether the paper ejection path 76 is opened or closed.

The copy paper 41 sent downward (FIG. 2) through the paper ejection switching section 70 is sent into the ADU 80 (stored in the ADU; step 2).

The copy paper 41 conveyed to the reversing conveyance section 80 is transferred to the stacker 8
It is reversed and released towards 3. At this time, the trailing edge of the ejected copy paper is detected by a stack sensor 84 composed of a photosensor or the like. Note that this stack sensor 84 constitutes a paper refeeding state detection means.

The ejected copy paper 41 slides on the surface of the stacker 83 and comes into contact with the abutting surface and stops. Subsequent copy sheets 41 that are subsequently sent in are also stacked one after another on the stacker 83.
By abutting against the abutting surface, the leading edge of the copy paper 41 is aligned.

In this state, when the ADU control unit 114 generates a paper refeeding start signal, the ADU drive unit 123 drives and rotates the roller 85, and the double-feed prevention roller 86 rotates counterclockwise. As a result, the plurality of copy sheets 41 stacked in the stacker 83 are sent out one by one from the bottom layer.

The copy paper 41 is then conveyed by the pressure rotation between the paper feed roller 87 and the paper feed roller 87', and the passage of the leading edge of the copy paper 41 is detected by an ADU passage sensor 88 composed of a photosensor. The copy paper 41 is subsequently conveyed and fed into the registration rollers 62 (step 2).

Thereafter, the second side (8th side) of the copy paper 41 is copied on the photoreceptor 30 (step ■), and the fixing unit 5
After being subjected to the fixing process, the paper passes through the reversal paper ejection processing section 76 of the paper ejection switching section 70 and is ejected to the outside of the machine.

In this way, the backside copying of the first copy paper 41 is completed by refeeding, and then a refeeding start signal is input.
The next copy sheet 41 waiting on the stacker 83
paper refeeding is started. After that, the above-mentioned paper refeeding operation,
The back side copying operation is performed continuously for the set number of copies N copies.

In addition, when the stack sensor 84 detects the passage of N sheets, the ADU
If the passage sensor 88 has not counted N sheets, a jam may have occurred, so jam processing (step 0) is performed.

If there is a document in the ADF 80, the above-described operations are repeated (steps ① to ①).

Here, the features of this embodiment will be explained with reference to FIG. 3.

The stack sensor 84 detects the stacking of the first document (first ready condition; FIG. 3(f)), and the paper passing sensor 63 (63a to 63c in FIG. 2) detects the set copy number N. The passing of a sheet of paper is detected (second ready condition, third ready condition).
(C)) and the timing control means 111 are ADU8
0 to refeed the paper (Fig. 3 (g)).

In the case of configuration 2, since the timing of refeeding paper from the ADU 80 is advanced, there is no waiting time between copying on the first side and copying on the second side, as shown in FIG. 3(i).

In the case of FIG. 3, the number of copies set is relatively large, and stack detection precedes the completion of first side paper feeding. Furthermore, when the set number of copies is small, as shown in FIG. 4, the completion of paper feeding on the first side precedes stack detection.

In any case, since copying of the second side is instructed to start at the timing when both conditions become ready, it is possible to minimize unnecessary waiting time. As a result, productivity during double-sided copying can be improved.

In actuality, under the above-mentioned timing instructions, the final copy sheet of the set number of copies on the first side or the registration roller 6 is
2, the re-fed copy paper from the ADU 80 reaches the registration roller 62, thereby minimizing wasted waiting time. Therefore, it is also possible to adjust the position of each sensor, adjust the time using a timer, etc.

(Effects of the Invention) As described in detail above, in the present invention, the copy paper on which the first side has been copied is reversed by the reversing transfer unit, and the second side is copied onto the copy paper sent out from the reversing transfer unit. In an automatic duplex copying device that performs the A paper refeeding state detection means detects that it is possible to refeed a sheet of paper, and a paper refeeding state detection means receives the detection output from the paper feeding state detection means and the paper refeeding state detection means and refeeds the paper to the reverse transfer section. and timing control means for giving a start instruction.

As a result, when it is detected that copy sheets from the paper feed section of the main body have been fed by the set number of copies, a detection output is generated by the paper feed state detection means, and at least one of the copy sheets stacked in the reverse transfer section is fed. When a sheet can be re-fed, a detection output is generated by the re-feed possible state detection means. Upon receiving these detection outputs, an instruction to start paper refeeding is given to the timing control means or the reversal transfer section.

Here, since the detection output is generated without waiting for the stacking of the set number of copies to be completed in the reverse transfer unit, the first side copy and the second
The waiting time between copying and copying can be minimized.

Therefore, the time from the end of copying on the first side to the start of copying on the second side can be shortened, and it is possible to realize an automatic double-sided copying apparatus that can improve productivity during double-sided copying.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the electrical configuration of an automatic double-sided copying apparatus according to an embodiment of the present invention, FIG. 2 is a block diagram illustrating the operating state of the apparatus of this embodiment, and FIG. 3 is a block diagram of this embodiment. FIG. 4 is a time chart for explaining the operating state of the apparatus; FIG. 4 is a time chart for explaining other operating states of the apparatus of this embodiment; FIG. 5 is the automatic double-sided copying apparatus of the embodiment shown in FIG. 1. FIG. 6 is a time chart for explaining the productivity of a conventional automatic double-sided copying apparatus. ]...Original 2.Platen glass]O.
・RADF 20・Optical system 30・・Photoconductor
40... Paper feed section 41, a to 41c... Copy paper 42a to 42c... Paper feed cassette 438 to 43c... Delivery rollers 44a to 44c... Delivery belt 50... Fixing unit 61 - Paper feeding Roller 62...Ren roller 63
・Paper passing sensor 70・・Paper discharge switching unit 80・ADU
84・Stack sensor 88・ADU passage sensor 100・・Control unit] 10・CPU 11 timing control unit] 12・・RADF control unit 113・・Photoconductor control unit 1] 4・・ADU control unit 15・Registration roller drive unit ]6...Paper feed 0-roller control unit 21・RADF drive unit 22...-Photoconductor drive unit 23...ADD drive unit 24...Registration roller drive unit 25...Paper feed roller drive unit

Claims (1)

[Claims] The copy paper whose first side has been copied is transferred to the reversal transfer unit (80).
In an automatic double-sided copying device that reverses the paper and copies the second side on the copy sheet sent out from the reversing transfer section (80), the copy paper from the main body paper feed section (40) has been fed by the set number of copies. a paper feeding state detection means (63) for detecting the state of paper refeeding, and a paper refeeding state detection means (63) for detecting that it is possible to refeed at least one sheet of copy paper stacked in the reversing transfer section (80); 84) and paper feeding state detection means (63)
and timing control means (111) for receiving the detection output from the paper refeeding state detecting means (84) and instructing the reversing transfer unit (80) to start paper refeeding. Copying equipment.