JPH06148958A - Copying machine - Google Patents

Abstract

PURPOSE:To provide a copying machine for both-side copying which reduces loss time at the both-side copying time of a both-side copying machine and whose copying efficiency is extremely high. CONSTITUTION:An image forming means forming an image on a form, an intermediate tray (3) housing the form (x) which is supplied from the image forming means and the image is formed and matching means (4 and 5) provided in the tray (3) freely movably so as to match the form (x) housed in the tray (3) are included. When the other forms (x) whose size is different from the forms (x) housed in the tray (3) are housed next by the tray (3), the matching means (4 and 5) are moved so as to match the other forms (x) when all the forms (x) housed in the tray (3) are removed from the matching means (4 and 5).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copying machine, and more particularly to a double-sided copying machine having a sheet aligning means in an intermediate tray.

[0002]

2. Description of the Related Art A double-sided copy process of a general double-sided copying machine will be described with reference to FIG.

In FIG. 15, the paper to be copied is fed from the cassette to the electrophotographic process section (15-1), and the image of the same original is transferred to the first side of the paper (15-2). Make a copy. The sheets copied on one side are stored in an intermediate tray in a reversing unit provided in the double-sided copying machine (15-3).
This is repeated (15-4) until the number of sheets to which the image of the same original is transferred on the first side is required for copying to the intermediate tray, that is, N sheets. After storing N sheets in the intermediate tray (15-
5), to re-feed the next original image to the other side (two sides) of this paper, from the intermediate tray to the electrophotographic process section in order.
(15-6) After the second side is transferred (double-sided copy) (15-7), the double-sided copied paper is ejected to the paper ejection tray (15-8). And
Repeat this until the transfer to the second side is completed N sheets (15-
9).

Here, the process section is in a standby state (loss time: t) until the Nth (last) sheet of the first surface transferred is stored in the intermediate tray. This loss time t
Is dependent on the transport length (L) and the transport speed (v) from the transfer section of the process section through the reversing section to the intermediate tray, t = L / v
Can be expressed as The loss time t is constant. Therefore, the double-sided copy, that is, the first-side and second-side copy (double-sided copy) time is the N sheet feeding (copying of the first side) time, the loss time t and the N sheet re-feeding (copying of the second side). ) It is the sum of time.

As described above, the smaller the copy number N is, the longer the time required for double-sided copying per sheet is.

At the time when the size of the sheet to be accommodated in the intermediate tray is determined next time, the sheet aligning operation suitable for the next size does not already exist in the reversing unit. Further, after the size to be copied next is determined, the aligning operation of the sheets having different sizes to be copied is performed.

As a general example, for example, JP-A-58-797
Reference numeral 1 denotes an image storage unit capable of storing image information corresponding to the first original image and image information corresponding to the second original image, and an image storage unit capable of storing image information stored in the image storage unit. An image forming means capable of reproducing an original image on the front surface or the back surface of the recording material, and the first image is formed on the front surface of the recording material by the image forming means according to the image information stored in the image storing means. Is reproduced and a second original image is reproduced on the back surface of the recording material.

[0008]

Therefore, in the conventional double-sided copying machine, since the sheet aligning operation is started after the sheet is completely removed from the reversing unit, the processing speed in the double-sided mode is high. -If the mixed originals of different sizes cannot be processed at high speed, and if the copying operation of the next original of different size is started after the matching operation of the next sheet size is completed, If the paper conveyance timing is delayed due to a defect, a delay in image processing, or the like, the copy efficiency is significantly reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide a copying machine for double-sided copying, which has a very high copy efficiency and can reduce the loss time in the double-sided copying of a general double-sided copying machine.

[0010]

SUMMARY OF THE INVENTION The present invention is directed to an image forming means for forming an image on a sheet, an intermediate tray for accommodating the image-formed sheet fed from the image forming means, and an intermediate tray. An aligning unit movably provided in the intermediate tray so as to align the sheets to be stored in the intermediate tray, and the intermediate tray next stores another sheet different in size from the sheet accommodated in the intermediate tray. Is characterized in that when all the sheets accommodated in the intermediate tray are separated from the aligning means, the aligning means starts to move to align other sheets.

[0011]

When the intermediate tray next accommodates another sheet having a different size from the sheet accommodated in the intermediate tray,
When all the sheets stored in the intermediate tray have been separated from the aligning means, the aligning means is configured to start moving to align other sheets, so even if sheets of different sizes are mixed, The sheets accommodated in the tray are preferentially processed, other sheets to be copied next can be aligned without delay in the copy operation, and even if sheets of different sizes are mixed, the copying can be performed efficiently.

Further, in the embodiment, when all the sheets accommodated in the intermediate tray are discharged from the intermediate tray and the size of the sheet to be copied next is determined, the aligning means moves to align other sheets. The start time of the PS roller is calculated before the image is formed so that the image processing means immediately forms the image on another sheet and feeds it to the intermediate tray after the completion of the movement and the completion time of the movement is calculated. Is adjusted to start the next copy processing, the start of the next copy processing is performed.
It is possible to easily control the timing of copying, and copy without loss time can be performed.

[0013]

First, the outline of an embodiment of a copying machine according to the present invention will be described.

In the embodiment of the copying machine according to the present invention, a photoelectric conversion element (CCD) provided in the copying machine converts an original image exposed and scanned into an electric signal, which is stored in a memory and required for copying. Data is printed on the paper via laser light. As a copying procedure, when copying from the reversing unit to the second surface can be smoothly executed without loss time, the re-feeding from the reversing unit is preferentially performed, and
Make a copy to the surface. On the other hand, in the above procedure, when the loss time occurs, the sheet is fed from the cassette side and the copy to the first side is executed.

That is, at the time of copy start, since there is no sheet having the first surface copied on the intermediate tray in the reversing unit, the sheets are copied from the cassette to the first surface sequentially. After that, the re-feeding can be executed from the reversing unit without any loss time, and the copying of the second surface is started.

After that, the copy efficiency of the second surface and the first surface can be improved by executing the double-sided copy operation which minimizes the loss time by the above-mentioned predetermined algorithm. It is a thing.

In order to better understand the present invention, the basic idea of loop duplex will be described.

First, a double-sided automatic document feeder (RDF or
Scan the originals in order with (ADF). At this time, the reading order is 1F, 1R, 2F, 2R, ... However, the numbers indicate the reading order of documents, F indicates the front side of the document, and R indicates the back side of the document.

The image data stored in the memory in the order of 1F, 1R, 2F, 2R ... Is printed as follows in the conventional system. That is, when there are many copies, 1F, 1F,
1F, ... 1F, 1F (number of copies required (N)), 1R,
1R, …… 1R, 1R (N sheets) 2F, 2F …… 2R, 2R (N sheets) When the number of copies is small (1 copy) 1F, 1F
・ (Loss time) ・ 1R, 2F ・ (Loss time) ・ 2R, 3F ・
(Loss time) 3R.

Next, the double-sided copy processing will be described with reference to FIG.

When the number of copies is large (for example, 4 copies), first, in the copy start, since there is no sheet whose first side is copied on the intermediate tray 3 of the reversing unit 11, the cassette 52 side The paper is fed, and is copied from one copy of 1F (copying 1F to one surface of the first sheet X1 in the electrophotographic process section 47, FIG. 2A).

After 1F-1 has started, a predetermined cycle time elapses, that is, 1F-1 starts and then 1F-2.
Copy (Copy 1F to the first side of the second sheet of paper X2, Fig. 2
(b)) The next copy is judged before the start. At this time as well, since there is no sheet that can be re-fed from the intermediate tray 3 as in the 1F-1 start, the next sheet X2 is continuously fed from the cassette 52 (FIG. 2 (b)).

In the same procedure, 1F-3 (1F is copied to one side of the third sheet X3, FIG. 2C) and 1F4 (1F is copied to one side of the fourth sheet X4). -, Fig. 3 (a)), that is, X1 ~
X4 sheets are fed sequentially from cassette 52, and 1F copy is performed. After the end of copying the first side of the X4 sheet and after the cycle time, in FIG. 3 (b), the leading edge of the sheet X1 discharged from the intermediate tray 3 is the refeed point, that is, the timing of copying 1R. Point P for judgment (Fig. 3
(b)) has arrived.

Then, in order to copy 1R onto paper X1, paper X1
Paper to process section 47 and copy 1R-1 (1R to paper X1
Copy to the two sides of Fig. 3 (c)). Similarly, after that cycle time, 1R-2 (1R is copied to two sides of paper X2, FIG. 4 (a)), 1R-3 (1R is copied to two sides of paper X3, FIG. 4).
(b)), 1R-4 (1R is a sheet of paper (copy to 2 sides of X4, Fig. 4
(c)) and the intermediate tray 3 after 1R-4 printing
Paper from cassette 52 (1F-5
That is, it automatically switches to paper feeding on one side of paper X5 and repeats these operations (Fig. 4 (d)).
) Complete the copy processing in multiple copies.

Even if the number of copies is small (1 copy), 1F-1, 2F-1, 3F-1, 4F-1, 1R-1, 2R-1, 3R-1, 4R-1,
Copy without loss time can be executed in order of 5F-1.

The copy efficiency at this time is shown in FIGS. 8 and 9.

FIG. 8 shows a general method, which is highly dependent on the number of copies and hardly depends on the number of originals.

FIG. 9 is a double-sided copy shown in FIGS.
Regarding the method, when the predetermined number is 5, the dependency by the number of copies is the same as the conventional method, but the efficiency is further increased.
In addition, the efficiency of the number of manuscripts also increases rapidly.

The feature of this method is that the efficiency rapidly rises to near 100% except for some combinations where both the number of copies and the number of manuscripts are small, and in some cases, it becomes 100%. To do.

Here, the predetermined number referred to in the present system is a value obtained by dividing the conveying path length by the length of the sheet to be used, in which the sheet is conveyed again from the photosensitive drum to the photosensitive drum through the reverse path. It is set to an appropriate upper limit of the number, and a value lower than that is usually used for ease of control.

The efficiency (E) according to this method is E = (M x
It can be expressed as N) X 100 / [M x N + (PA)] (%).

However, M is the number of originals, N is the number of copies,
P is a predetermined number, and A is the remainder when (M x N) / 2 is divided by P (when the remainder is zero, A = P). It can be seen that the efficiency is 100% when (M x N) is a multiple of P. Next, a digital copying machine will be described as an example of the copying machine of the present invention.

FIG. 6 is a sectional view showing the overall construction of a digital copying machine 30 which is an embodiment of the present invention.

As shown in FIG. 6, the copying machine 30 is provided with a scanner section 31, a laser printer section 32 as an image forming means, a multi-stage sheet feeding unit 33 and a sorter 34.

The scanner unit 31 is composed of a document placing table 35 made of transparent glass, a double-sided automatic document feeder (RDF) 36, and a reading unit, that is, a scanner unit 40.

The multi-stage paper feeding unit 33 includes a first cassette 52,
Second cassette 53 and third cassette that can be added by selection
Has 55.

In the multi-stage sheet feeding unit 33, the sheets are fed out one by one from the sheets stored in the cassettes of the respective stages.
It is conveyed toward the laser printer unit 32.

The RDF 36 sets a plurality of originals at a time, automatically feeds the originals one by one to the scanner unit 40, and scans one side or both sides of the original according to the operator's selection. It is configured to be read by the unit 40.

The scanner unit 40 includes a lamp reflector assembly 41 for exposing a document, a plurality of reflection mirrors 43 for guiding a reflected light image from the document to a photoelectric conversion element (CCD) 42, and a reflected light image from the document for CCD 42. It includes a lens 44 for imaging.

When scanning a document placed on the document placing table 35, the scanner section 31 is configured to read the document image while the scanner unit 40 moves along the lower surface of the document placing table 35. And when using RDF36,
The document image is read while the document is being conveyed while the scanner unit 40 is stopped at a predetermined position below the RDF 36.

The image data obtained by reading the original image with the scanner unit 40 is sent to an image processing unit (not shown), which will be described later, and after being subjected to various processes, is temporarily stored in the memory of the image processing unit. The image data stored in the memory is supplied to the laser printer section 32 in accordance with the output instruction to form an image on a sheet.

The laser printer unit 32 is a manual document tray 4
5. A laser writing unit 46 and an electrophotographic process unit 47 for forming an image are provided.

The laser writing unit 46 is a semiconductor laser which emits laser light corresponding to image data from the above-mentioned memory, a polygon mirror which deflects the laser light at an equal angular velocity, and a constant angular velocity deflection. The laser light thus generated is corrected so that it is deflected at a constant speed on the photosensitive drum 48 of the electrophotographic process section 47.
It has a θ lens and the like.

The electrophotographic process section 47 has a charging device, a developing device, a transfer device, and
A peeling device, a cleaning device, a static eliminator, and a fixing device 49 are arranged.

A transport path 50 is provided downstream of the fixing device 49 in the transport direction of the sheet on which an image is to be formed.
50 is a conveying path 57 leading to the sorter 34 and a multi-stage paper feeding unit
It branches into a conveyance path 58 leading to 33, and the conveyance path 58 leads to the reversing unit 11 of the multi-stage sheet feeding unit 33.

The multi-stage paper feeding unit 33 includes a common transport path 56, and the common transport path 56 includes the first cassette 52 and the second cassette 52.
The paper from 53 is carried out toward the electrophotographic process section 47.

The common conveying path 56 joins the conveying path 59 from the third cassette 55 on the way to the electrophotographic process section 47 and communicates with the conveying path 60.

The transport path 60 is constructed so that it merges with the transport path 61 from the manual document tray 45 at a confluence point 62 and leads to an image forming position between the photosensitive drum 48 of the electrophotographic process section 47 and the transfer device. The confluence point 62 of these three conveyance paths is provided at a position close to the image forming position.

Therefore, in the laser writing unit 46 and the electrophotographic process unit 47, the image data read from the above-mentioned memory is exposed by scanning the laser beam by the laser writing unit 46. The toner image formed as an electrostatic latent image on the surface of the body drum 48 and visualized by the toner is electrostatically transferred and fixed on the surface of the sheet conveyed from the multi-stage paper feeding unit 33. The sheet on which the image is formed in this way is sent from the fixing device 49 to the sorter 34 via the transport paths 50 and 57, or is transported to the reversing unit 11 via the transport paths 50 and 58.

Next, the structure and function of the image processing unit included in the copying machine 30 will be described.

FIG. 7 is a block diagram of the image processing unit included in the copying machine 30 of FIG.

The image processing unit included in the copying machine 30 includes a memory 73 including an image data input unit 70, an image processing unit 71, an image data output unit 72, a RAM (random access memory), and the like. And a central processing unit (CPU) 74.

The image data input unit 70 includes a CCD unit 70a, a histogram processing unit 70b and an error diffusion processing unit 70c.

The image data input unit 70 binarizes and converts the image data of the original read from the CCD 42 of FIG. 3 to obtain a histogram as a binary digital amount, and image data by the error diffusion method. The data is processed and temporarily stored in the memory 73.

That is, in the CCD unit 70a, analog electric signals corresponding to the respective pixel densities of image data are A / D converted, and then MTF correction, black and white correction or gamma correction is performed.
It is output to the histogram processing unit 70b as a digital signal of 6 gradations (8 bits).

In the histogram processing section 70b, the CCD section 70a
The digital signal output from the is added for each pixel density of 256 gradations to obtain density information (histogram data), and if necessary, the obtained histogram data is
The error diffusion processing unit 70 is sent to the CPU 74 and also as pixel data.
sent to c.

In the error diffusion processing unit 70c, the error diffusion method which is a kind of pseudo halftone processing, that is, the method of reflecting the binarization error in the binarization judgment of the adjacent pixel is output from the CCD unit 70a. A digital signal of 8 bits / pixel is converted into 1 bit (binary), and a redistribution operation for faithfully reproducing the local area density in the original is performed.

The image processing section 71 is a multi-value processing section 71a and 71.
b, synthesis processing unit 71c, density conversion processing unit 71d, scaling processing unit
71e, an image processing section 71f, an error diffusion processing section 71g, and a compression processing section 71h.

The image processing unit 71 is a processing unit for finally converting the input image data into the image data desired by the operator, and the output image data finally converted into the memory 73. It is configured to be processed by this processing unit until it is stored as a data. However, each of the above-described processing units included in the image processing unit 71 functions as necessary and may not function.

That is, in the multi-value quantization processing units 71a a and 71b,
The binarized data is again converted into 256 gradations by the error diffusion processing unit 70c.

In the synthesis processing section 71c, the logical operation for each pixel,
That is, the operation of logical sum, logical product, or exclusive logical sum is selectively performed. The data that is the target of this calculation is the memory 73
Pixel data and pattern generator stored in
This is the bit data from (PG).

In the density conversion processing unit 71d, 256 gradation data
With respect to the input signal, the relationship between the input density and the output density is arbitrarily set based on a predetermined gradation conversion table.

In the scaling processing unit 71e, the pixel data (density value) for the scaled target pixel is obtained by performing interpolation processing with known data that is input according to the designated scaling ratio. The main scanning is scaled after the sub scanning is scaled.

In the image processing section 71f, various image processings can be performed on the input pixel data, and information collection such as feature extraction can be performed on the data sequence.

The error diffusion processing unit 71g performs the same processing as the error diffusion processing unit 70cc of the image data input unit 70.

In the compression processing unit 71h, binary data is compressed by the encoding called run length. Regarding the compression of image data, the compression works in the final processing loop when the final output image data is completed.

The image data output section 72 includes a restoration section 72a, a multi-value processing section 72b, an error diffusion processing section 72c, and a laser output section 72.
Contains d.

The image data output section 72 is a memory in a compressed state.
The image data stored in 73 is restored, converted back to the original 256 gradations, and the error diffusion of the four-valued data, which is a smoother halftone expression than the binary data, is performed. -The output section 72d
Is configured to transfer the data.

Immediately, the decompression unit 72a decompresses the image data compressed by the compression processing unit 71h.

In the multi-value quantization processing unit 72b, the same processing as that of the multi-value quantization processing units 71a a and 71b of the image processing unit 71 is performed. The error diffusion processing unit 72c performs the same processing as the error diffusion processing unit 70C of the image data processing unit 70.

In the laser output section 72d, the digital pixel data is converted into a laser on / off signal based on a control signal from a sequence controller (not shown).
The laser is turned on / off.

The data handled by the image data input unit 70 and the image data output unit 72 is basically stored in the form of binary data in order to reduce the capacity of the memory 73. Although it is stored in 73, it is also possible to process in the form of four-valued data in consideration of the deterioration of the image data.

FIG. 1 is a schematic sectional view of the reversing unit 11 and its vicinity.

First, the outline of the movement of the paper and the operation of the reversing unit 11 will be described.

The sheet X on which the image has been fixed on the first side is passed through the reversing paper guide 2 and stored in the intermediate tray 3. When paper is supplied to the intermediate tray 3, the paper feed plate 1
Is held in the OFF state (upper side in FIG. 1).

Simultaneously with the storage of the paper X, the paper X is moved along with a rack 6, a pinion 7, a drive motor DMOT, and a switching solenoid DSLO2, which will be described later, and constitutes a matching means. Aligned with respect to width and length. After the alignment is completed, the paper X is reversed and re-fed. At this time, the sheet feeding plate 1 is held in the ON state by the solenoid DSLO1, the sheet discharge is detected by the DES (duplex empty sensor), and the sheet X is fed by the sheet feeding plate 1 to the sheet feeding roller B. When the sheet X is pressed, the sheet X is fed with a conveying force, is separated by the separating roller C, is conveyed through the conveying rollers D, E, F, and G, and is re-input into the conveying path of the main body. .

The sheet sent out from each sheet cassette (not shown) is conveyed in the direction of arrow a from the lower right side of the reversing unit 11. When the sensor PSS detects the paper from the paper accommodating portion, the transport roller J is once stopped and restarts in time with the other transport portions. The sheet that has passed the conveying / merging portion is conveyed to the transfer portion of the process portion 47 via the conveying rollers H and PS rollers 63. The PS roller 63 starts its operation in accordance with the image front end of the toner image formed on the photosensitive drum 48, and feeds the paper X sandwiched between the nips.

The paper on which the predetermined image is stored on the recording surface is discharged to the paper discharge tray side after passing the fixing unit, or
It is guided to the reversing unit 11 side or switched according to the copy mode.

In the case of double-sided copying, the paper X conveyed through the gate is guided to the reversing unit 11 side. The sheet X conveyed from the upper left portion of the reversing unit 11 is temporarily guided to the intermediate tray 3. At this time, when the sensor DS1 detects the leading edge of the paper, the state of the solenoid DSOL1 is checked, and the paper feed plate 1 turns off the solenoid DSLO1 acting on the trade-in paper feed roller B side as shown in the figure to turn off the paper feed plate. 1 is rotated in the direction of the arrow (OFF) from the state shown in the figure.

That is, the paper feed plate 1 is retracted upward so as not to interfere with the conveyance of the paper X when the paper X is inserted. The side edge regulating plate 4 and the trailing edge regulating plate 5 provided on the intermediate tray 3 are set in accordance with the size of the sheet sent to the intermediate tray 3 in advance, that is, the size of the sheet set in the designated sheet cassette. It can be moved back and forth and left and right.

With respect to the paper X once stored in the intermediate tray 3, the solenoid DSOL1 is turned on at the timing when the succeeding paper is not conveyed to the paper reversing section, and the paper is moved from above to the trade-in roller B side (ON). Pressed.

At this time, since the roller B is rotating in the direction of the arrow, the paper X stored in the intermediate tray 3 is fed leftward. Paper X sent by this roller B
Are then separated one by one by the separating roller C so that they will not be double fed. It is the friction member 6 that is in contact with the separating roller C, and if a double feed of paper occurs, only the bottom paper is sent to the next process,
The other papers are prevented from being transported by the friction member 6.

The sensor DS2 is arranged to detect the leading edge of the separated sheet, and if the sensor DS2 is not turned on within a predetermined time after the trade-in sheet feeding of the previous process is performed, it is determined as a sheet feeding error. It is processed.

If the sensor DS2 is turned on within a predetermined time, it means that the operation is good and the process proceeds to the next step. After DS3 is turned on via the transport rollers D and E, DS4 is turned on after passing through the transport roller F, and when the leading edge of the paper is caught in the transport roller G, the transport roller is turned on. -Stop La G and F. In this transport path, the length between the transport rollers G and F is set to at least one B5 plate.

Then, when the succeeding paper X turns on the sensor DS3, one succeeding paper (A4 or B5 size) is placed in the area between the sensor DS3 and the transport rollers D and E, and further another succeeding paper. When the sensor DS2 is turned on, if the sheet is A4 size or B5 size, the trailing edge portion of the succeeding other paper is positioned on the intermediate tray 3 from the roller D through the area of the sensor DS2 and the sorting roller C. And the three sheets are stopped.

At this time, when the largest sheet, for example, the A3 size sheet is stopped from the roller D to the area of the sensor DS2 and the sorting roller C, the rear end of the A3 size sheet is The edge regulating plate is located downstream of the position where the length of the smallest sheet, for example, the B5 size sheet, is aligned with respect to the sheet discharge direction.

When the sheets are all A4 size or B5 size,
After the fourth sheet of paper, all the previous three sheets of paper have stopped in the transport path, and are therefore stored in the intermediate tray 3.

That is, the rear end portion of the third sheet and the fourth sheet partially overlap in the intermediate tray 3. The previous transport roller G is used for other transport rollers H and PS rolls.
If the sheet is restarted while keeping the timing with the printer 63, the succeeding paper X is also restarted sequentially.

This time, all the paper sizes have been described by exemplifying A4 and B5 plates. However, there are cases where all paper sizes are A3 and B4 plates, and when A3, B4, A4 and B5 plates are mixed. is there.

When the A3 or B4 size sheet stops at the conveyance roller G at the beginning, it is about twice as long as the A4 or B5 size sheet and the conveyance roller G to the conveyance roller E. Will occupy the transport path. This state is the same regardless of which transport roller position is stopped.

That is, when the A4 or B5 size sheet stops at the transport roller G and the A3 or B4 size sheet stops at the sensor DS3, the A3 or B4 size sheet is stopped. The rear end is positioned on the intermediate tray 3 and stops.

When a sheet is accommodated in the intermediate tray 3 and the sheet feed plate 1 acts at a predetermined sheet feed timing to press the sheet X against the roller B, the succeeding sheet is supplied to the reversing unit 11. When this is detected by the sensor DS1, the operations of the roller B and the sheet feeding plate 1 are once stopped.

That is, the succeeding paper X is the reversing unit 11
When the sheet is fed toward the intermediate unit 3, the sheet feeding plate 1 is retracted upward and priority control is performed so that the succeeding sheet X does not collide with the sheet feeding plate 1.

Finally, when the feeding of the sheet from the conveying roller G is restarted at the timing of the sheet sent from the cassette, the sheet is again transferred via the conveying roller H and the PS roller 63. Then, another image different from the front surface is formed on the back surface of the sheet.

In FIG. 6, the sheet on which the toner image is formed passes through the fixing section and is discharged to the sheet discharge tray side by the switching gate.

FIG. 5 is a sectional view for explaining the outline of the operation of the reversing unit.

In the normal double-sided copy mode, the sheet once stopped is re-fed at a predetermined timing from the roller G, but the re-feeding of the sheet from the reversing unit 11 is predetermined. When the image processing requires more than one cycle of copy time, the paper in the conveyance path of the reversing device 11 must be stopped (roller in FIG. 5). Paper X located from B to roller G).

Therefore, in this embodiment, the intermediate tray 3
Then, the succeeding one-side copied sheets X are stacked. On the other hand, in order to prevent the copy efficiency of the total from being lowered, if one side can be copied, the sheet X is fed from the cassette 52 and the one side is copied (FIG. 5). .

In this embodiment, the solenoid DSOL1 is turned on until the sensor DS2 detects the leading edge of the fed sheet, and the solenoid DSOL1 is actuated on the roller B side of the sheet feeding plate 1; It may be configured to operate for a predetermined time.

This predetermined time is the time until the paper feed plate 1 presses the paper X stored in the intermediate tray 3 toward the roller B and at least the leading edge of the paper X reaches the paper separating roller C. And it is sufficient.

As described above, by effectively utilizing the conveying path of the reversing unit 11, the processing efficiency in the double-sided mode of the double-sided copying machine can be greatly improved.

Next, the operation of the side end regulating plate 4 and the rear end regulating plate 5 will be described with reference to FIGS.

The pinion 7 is rotated immediately before the sheet X is fed to the intermediate tray 3, and the side edge regulating plate 4 provided on the rack 6 is rotated by the rotation of the pinion 7 to have a width slightly larger than the size of the sheet accommodated. Move to position (Fig. 10). For example, if the set size is A4, the first set value of width is the second set value 297mm +
4 mm = 303 mm.

When the sheets enter the intermediate tray 3, the side edge regulating plates 4 first move so that the width becomes the first set value (303 mm in the case of A4), and then the width increases from the outside to the inside. Move to the 2nd setting value (297 mm for A4) (A
In case of 4, adjust the gap by 2 mm) (Fig. 11).

Similarly, the length is adjusted by moving the rear end regulating plate 5.

The rotation of the pinion 7 and the movement of the trailing edge regulating plate 5 are carried out, for example, via a matching plate driving motor (pulse motor).

By effectively utilizing the reversing unit in this way, the processing efficiency in the double-sided mode of the copying machine can be greatly improved.

Next, the operation of the matching means will be described with reference to FIGS.

In FIG. 13, it is judged whether or not the size of the paper to be copied next is judged (13-1). If determined, it is determined whether or not all the sheets accommodated in the intermediate tray are separated from the aligning means (13-2). When all of them are separated, the side end regulating plate 4 and the rear end regulating plate 5 of the aligning means are started to move to a position corresponding to the size of the sheet to be copied next (13-3).

In this case, as shown in FIG. 14, after the movement of the aligning means is started (14-1 to 14-3) as in the case of FIG. 13, the movement completion time defined by the size of the sheet is CP by the movement amount.
Calculated by U timer control (14-4), start timer (14-5), start image formation (14-6), and start PS roller 63 Good (14-7). The PS roller 63 calculates the moving time from the current alignment position after the paper size is fixed, and the PS roller 63
Due to the difference between the paper transport time from 63 to the alignment section, PS roll
The operation timing of 63 is controlled by the CPU.

[0111]

When the intermediate tray accommodates another sheet having a size different from that of the sheet accommodated in the intermediate tray, the aligning means when all the sheets accommodated in the intermediate tray are separated from the aligning means. Is configured to start moving to align other papers, so even if papers of different sizes are mixed, the papers stored in the intermediate tray are processed preferentially and the other papers to be copied next. The sheets can be aligned without any delay in the copy operation, and the sheets can be efficiently copied even when sheets of different sizes are mixed.

[Brief description of drawings]

FIG. 1 is a sectional view for explaining a reversing unit of an embodiment of a copying machine of the present invention.

FIG. 2 is a diagram for explaining a first operation of the reversing unit of FIG.

FIG. 3 is a diagram for explaining a second operation of the reversing unit of FIG.

FIG. 4 is a diagram for explaining a third operation of the reversing unit of FIG.

5 is a cross-sectional view for explaining the outline of the operation of the reversing unit in FIG.

FIG. 6 is a sectional view showing a main part of an embodiment of a copying machine of the present invention.

FIG. 7 is a block diagram of an image processing unit included in the embodiment of the copying machine of the present invention.

FIG. 8 is a diagram showing the efficiency of a general double-sided copy process.

FIG. 9 is a diagram showing efficiency regarding a double-sided copy processing according to an example.

FIG. 10 is a schematic plan view showing a side end regulating plate and a rear end regulating plate.

FIG. 11 is a schematic side view showing a side end regulating plate and a rear end regulating plate.

FIG. 12 is a diagram illustrating alignment of sheets.

FIG. 13 is a flowchart for explaining the first operation of the matching means.
It is

FIG. 14 is a flowchart for explaining the second operation of the matching means.
It is

FIG. 15 is a flowchart relating to double-sided processing of a general copying machine.

[Explanation of symbols]

 1 Paper feeding plate 3 Intermediate tray 4 Side edge regulating plate 5 Rear edge regulating plate 11 Reversing unit 30 Copier 48 Photosensitive drum B Roller X Paper

Claims (2)

[Claims] 1. An image forming unit for forming an image on a sheet,
An intermediate tray that accommodates a sheet on which an image is formed and that is fed from the image forming unit, and a sheet that is accommodated in the intermediate tray are movably provided in the intermediate tray so as to align the sheets in the intermediate tray. When the intermediate tray accommodates another sheet different in size from the sheet accommodated in the intermediate tray, all the sheets accommodated in the intermediate tray are separated from the aligning means. The copying machine, wherein the aligning means is configured to start moving to align other sheets at the point of time. 2. The image forming means can adjust the timing of forming an image on another sheet in order to feed the other sheet on which the image is formed to the intermediate tray after the movement of the aligning means is completed. The copying machine according to claim 1, wherein the copying machine is configured as follows.