JPH066544A - Copying machine - Google Patents

Abstract

PURPOSE:To enhance the efficiency of double side copying and to improve the productivity by detecting number of original paper sheets, changing an original feed interval and sectioning a number of sheets in response to the copying mode and forming an image in the order of front and rear sides for each of the same number of sheets. CONSTITUTION:An original rear detection unit SIRU selects either the both side read mode or the one-side read mode based on the result of detection a rear of an original. Then number of fed originals is detected and the original feed interval and the section number of sheets are controlled in the copying mode, the originals of a prescribed number of sheets is fed to a picture read section IRU and the front side picture is sequentially read. Then the rear picture of the original is read via a switch-back section SB and a re-feed paper path 58. Thus, a forming section 2 able to form the picture on both sides of the paper forms the picture on both front and rear sides of paper. Thus, the double side copying efficiency is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic copying apparatus characterized by a document reading section.

[0002]

2. Description of the Related Art In a copying apparatus of this type, a document image read by a document reading section is exposed on a photosensitive drum to form an electrostatic latent image, and then toner is supplied to the electrostatic latent image. A toner image (visible image) is formed, and this toner image is further transferred to a fed sheet of paper and then fixed to obtain one copy. The copying apparatus is generally composed of a document reading section and an image forming section, and each section is provided with a document feeding apparatus and a sheet feeding apparatus, respectively. In the document scanning section,
The document sent by the document feeder is read by the reading optical system, converted into image data, and then transmitted to the image forming unit.

On the other hand, there is a double-sided copying apparatus such as a digital copying machine with an image reader, which is capable of copying both front and back sides of a document. Such an apparatus includes a document reading unit capable of reading both front and back sides of a document and an image forming unit capable of forming images on both front and back sides of a sheet. Then, the operator can select and use a double-sided copy mode in which an image is formed on both sides of the sheet or a single-sided copy mode in which an image is formed on one side of the sheet, as needed. In addition, in the image forming unit of such an apparatus, a normal image forming path (a sheet feeding path for feeding a sheet from the sheet storing section to an image forming position in order to form an image on the surface of the sheet), Refeed path 2
One paper feed path is provided. Here, regarding the re-feed path, when the single-sided copy mode is selected, the sheet is allowed to pass through to the downstream side as it is, but when the double-sided copy mode is selected, the sheet is switched back to display the sheet. It is designed such that it is returned to the image forming path in a state where the back surface is reversed.

Further, in the case of continuously forming images on both sides of a plurality of sheets of paper, if images are formed on both sides of each sheet of paper, while the sheets are moving along the re-feed path, In this case, the next image forming operation must be stopped, and the number of sheets of paper that can form an image per unit time (throughput) is significantly reduced. Therefore, USP 4,499,500 specification and US
A copying machine such as that disclosed in P4,568,169 has been proposed. That is, according to the copying apparatus disclosed in the former specification, while a sheet is moving in the re-feeding path, another sheet is fed to the image forming path so that the next image is formed. It has become. Further, according to the copying apparatus disclosed in the latter specification, a plurality of sheets are stored in the image forming path and the re-feeding path, and the re-feeding path conveys the sheets according to the number of stored sheets and the sheet size. You can change the speed.

On the other hand, with respect to the document reading unit, usually, a plurality of documents placed on the document placing unit are sequentially conveyed one by one, and the document is passed through the reading portion of the reading optical system. The image is read. Then, the read document is ejected and stored as it is on the ejection tray. Also,
As the reading means, a type of reading by such follow shot, and a document conveyed by the ADF are temporarily stopped,
There is a type that scans by scanning the optical system.

When it is necessary to read both sides of the original, the original on which the first side has been read is inverted, the direction is changed, and the original is supplied again to the reading optical system. The reading is performed, and then the document whose second side has been read is discharged onto the discharge tray. As described above, the conveyance direction of the document supplied to the reading optical system is opposite between the front side reading and the back side reading.

[0007]

However, when attempting to read both sides of an original with such an original reading unit, the original is moved in an inverted state so that its back side can be read, Obviously, it is necessary to pause the next reading operation of the document surface while the image is being supplied again to the reading optical system. As a result, the number of manuscripts that can be read per unit time significantly decreases with respect to the reading ability of the manuscript reading unit.

Therefore, in the conventional copying apparatus capable of double-sided copying, although the reduction of the number of sheets on which an image can be formed per unit time can be prevented to some extent by improving the image forming section as described above, the original reading section does not. However, it cannot be prevented that the number of read sheets per unit time decreases. Therefore, it is difficult for the copying apparatus to increase the number of copies, that is, improve productivity.

On the other hand, regarding the interface connecting the image reading unit and the image forming unit, it is ideal to store the image data of the read screen, process the information, and then output an arbitrary image to the image forming unit. However, the following problems occur when such a method is adopted. That is, it takes time to read the entire screen, which hinders the speedy printing work. In addition, when the number of images to be read is large (for example, about 50 pages), a huge memory is required, which results in an increase in cost.

On the other hand, when the capacity of the image memory is about one page of the original, it is necessary to read the original one page at a time and output it to the image forming section, which results in a large productivity. Will fall. The present invention has been made in view of the above circumstances, and efficiently performs both-side reading of a document and two-side copying of a sheet performed corresponding to the both sides.
It is an object of the present invention to provide a copying machine capable of significantly improving productivity.

[0011]

In order to achieve the above-mentioned object, the present invention provides a copying apparatus provided with a document reading section and an image forming section capable of forming images on both sides of a sheet, wherein the document reading section is provided. A document reading unit for reading a document image, a document feeding unit for automatically feeding the document to the document reading unit, a document discharging unit for discharging the read document, and a switchback unit for switching back the read document. The switched-back document is circulated, and the transport direction is switched so as to transport the document to the document re-feeding unit that feeds the document reading unit from the upstream side again and the document discharging unit or the switchback unit. A document conveying direction switching means, a document passing number detecting means for detecting the number of passed sheets of a document, and a control for controlling the document feeding interval and the number of separated sheets according to the copy mode. It is characterized in that a means.

Further, the present invention is characterized in that the document reading means changes the document reading interval depending on the copy mode. Furthermore, the present invention is characterized in that the document supply unit and the document circulation re-supply unit divide the document into a predetermined number of sheets according to the copy mode and supply the document to the document reading unit.

Further, according to the present invention, the original supply means and the original circulation resupply means have a predetermined number of originals depending on the number of copies, the number of originals to be circulated, or a combination of the number of originals and the number of originals to be circulated. It is characterized in that it is supplied to the document reading means in a divided manner.

[0014]

According to the above construction, the document read by the document reading means is discharged outside the apparatus by the document discharging means. Further, in the case of double-sided reading, the original after the front side has been read is conveyed to the switchback means by the original conveyance direction switching means, switched back there by the switchback means, and then further conveyed by the original circulation resupply means. It is supplied again from the upstream side of the reading means.

Further, the number of originals that can be fed to the original reading means is detected by the number of originals passed. Furthermore,
By the control means, the document feeding interval for each copy mode,
The number of breaks is controlled. Further, the document reading unit changes the document reading interval depending on the copy mode. Further, the document supply unit and the document circulation re-supply unit divide the document into a predetermined number of sheets according to the copy mode and supply the document to the document reading unit.

Further, the document supply means and the document circulation re-supply means divide the document into a predetermined number of sheets according to the number of copies, the number of documents to be circulated, or a combination thereof, and supply the documents to the document reading means.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a front sectional view showing a copying apparatus according to the present invention. In FIG. 1, reference numeral 1 is a main body of the printing apparatus, which has a photosensitive drum 2a, a charger, and
A well-known electrophotographic image forming unit 2 including an exposure optical system, a developing device, a transfer charger, a drum cleaner, and the like is provided. Reference numerals 3a, 3b, 3c denote paper feed cassettes mounted on one side of the main body 1, and the image forming is performed from the selected paper feed cassettes by the corresponding paper feed rollers 4a, 4b, 4c via the register roller 5. The sheet is fed toward the transfer section 6 between the photoconductor drum 2a and the transfer charger in the section 2. The sheet on which the image has been transferred by the transfer unit 6 is fixed by the fixing unit 7, and then discharged by the discharge roller 8 to the duplex unit 1.
Sent to 0. In the lower part of the main body 1, in order to re-feed the sheet sent from the duplex unit 10 toward the register roller 5, the conveying rollers 9a, 9
A sheet re-feeding path 9 in which b and 9c are arranged is provided.

The duplex unit 10 includes:
A carry-in roller 11 that receives the paper discharged from the main body 1.
A first switching claw 14 is provided between the sheet discharging roller 13 for discharging the sheet and the sheet to the sheet discharging tray 12, and the first switching claw 14 is provided.
It is configured to select whether to send the paper to the discharge tray 12 or to the second switching claw 16 via the transport roller 15 that can rotate in the normal and reverse directions. Second
The switching claw 16 is configured to select whether the paper is sent to the switchback path 17 or to the refeed path 9 via the sending roller 19. Reference numeral 18 denotes a transport roller that can rotate in the forward and reverse directions of the switchback path 17, and P denotes a sheet reversal point.

Reference numeral 20 is an optional paper feeding unit, 21 is a paper feeding roller thereof, and 22a and 22b are conveying rollers. 23
a, 23b and 23c are the paper feed cassettes 3a, 3b,
A well-known paper size detecting means arranged at the lower part of 3c, which is composed of a plurality of micro switches and the like, and has a paper size and length,
It is detected in which of the horizontal directions it is installed (see, for example, JP-A-63-70865).

The outline of the main operation in each image forming mode will be described. In the case of the single-sided mode, the first switching claw 14 causes the image forming sheet carried into the duplex unit 10 to the discharge tray 12. It is set to the position to guide. In this state, a desired size of paper is selectively fed from any of the paper feed cassettes 3a to 3c and the optional paper feed unit 20. The fed paper is transferred by the register roller 5 at the timing when the leading end of the paper is aligned with the image formed by the image forming unit 2.
Sent to. Here, the sheet is subjected to fixing processing by the fixing unit 7 after the transfer of the image on the upper surface thereof. Then, the first switching claw 14 is carried into the duplex unit 10 after that.
Guide, the sheet is discharged face-up, that is, the image forming surface is directed upward.

Further, in the double-sided mode, the first switching claw 14
Is switched to a position for guiding the sheet carried into the duplex unit 10 to the re-feed path 9 side, and the second switching claw 16 is guided to the re-feed path 9 side by the first switching claw 14. The sheet is switched to a position where the sheet is guided to the switchback path 17 and the sheet fed from the switchback path 17 is guided to the sheet refeed path 9. Therefore, the sheet that is carried into the duplex unit 10 after image formation and guided to the sheet re-feed path 9 side by the guide of the first switching claw 14 is sent to the switchback path 17 by the guide of the second switching claw 16. To be When the trailing edge of the sheet reaches the reversal point P, the transport roller 18 rotates in the reverse direction, and the sheet is guided to the delivery roller 19 side by the second switching claw 16 and delivered to the sheet re-feeding path 9 of the main body 1. . The sheet reaches the register roller 5 again through the sheet re-feeding path 9, the register is adjusted, and the image of the second side created in the image forming section 2 by the transfer section 6 is transferred to the back side of the sheet and fixed. It is fixed in the section 7, and the discharge roller 8
The sheet is discharged onto the sheet discharge tray 12 through the carry-in roller 11, the first switching claw 14, and the sheet discharge roller 13.

The above is the case of forming an image on one sheet of paper. However, when performing the image formation of the above-mentioned double-sided mode on a plurality of sheets of paper, the register roller 5 passes through the re-feeding path 9 to the register roller 5. The throughput can be increased by forming a plurality of sheets of paper in the returning sheet circulation path to form an image, and the throughput increases as the number of sheets of paper contained increases.

The maximum number of built-in sheets is the sheet-passage path length until the sheet fed from each sheet-feeding section returns to the register roller 5 through the duplex unit 10 and the sheet re-feeding path 9, and the sheet size. And the paper feed interval. The sheet feeding interval varies depending on the image information amount for each page and the processing capacity of the image forming controller 31. Further, the paper path length differs depending on whether or not the paper is introduced into the switchback path 17. That is, when the paper is introduced to the switchback path 17 in the double-sided mode,
It becomes longer by the amount of. As for the transport roller 18 of the switchback path 17, the roller 18a on the right side of FIG. 1 is a driving roller and the left roller 18b is a driven roller. Then, when the sheet introduced into the switchback path 17 is switched back by the reverse rotation drive of the roller 18a and sent to the sending roller 19, the sheet is reliably sent to the refeeding path 9 by the carrying force of the sending roller 19 thereafter. .

Here, the driving roller 18a of the conveying roller 18
Is set to be smaller than that of the transport roller 19, and the transport roller 19 causes the switchback path 17 to move.
Even if the drive roller 18a is switched to the normal rotation drive again while the sheet is being pulled out from the sheet, the pull-out is not affected, and the next sheet can be introduced into the switchback path 17 where the sheet is pulled out without trouble. . Therefore, in the double-sided mode, it is not necessary to change the paper interval in order to use the switchback path 17.

Therefore, in order to perform a large number of image forming operations in the double-sided mode, a sheet of paper of a size necessary for the image information that the image forming controller 31 receives from the host computer at any time is used as the image information amount and the image forming controller 31. Images are sequentially formed on the first side while sequentially feeding the sheets at an interval according to the processing capacity. Then, the sheet after the first image formation is built into the conveying path without being stopped while being fed to the sheet re-feeding path 9 through the switchback path 17. Then, the first sheet to be used for image formation on the second side passes through the re-feeding path 9 at a predetermined position before the image forming unit 2, that is, the first sheet to be re-fed is newly added. This is detected when the position is reached immediately before the sheet overlaps with the sheet to be fed, and if this is detected, the image forming operation is switched to the next image forming operation in which no new sheet is fed. As a result, the image forming operation is performed while the maximum number of sheets corresponding to the amount of image information and the processing capacity of the image forming controller 31 is built in, and the sheet to be re-fed and the sheet to be newly fed are overlapped. It is possible to surely avoid it, and to perform a large number of images in the double-sided mode with high efficiency.

The timing differs depending on the paper size, the paper feed cassettes 3a to 3c, and the distance from the optional paper feed unit 20 to the transfer unit 6 where an image is formed on the paper. The positional condition for detecting this timing will be described based on the schematic diagram shown in FIG. FIG. 2 shows the paper pn that has been fed in the case of sequentially feeding JIS standard A4 size horizontal paper from the optional paper feeder 20 and the first paper that has been re-fed through the re-feed path 9. The relationship with the paper pm is shown. The line (a) in FIG.
The peripheral length of the photoconductor drum 2a is indicated by Z, and Z indicates the exposure position for printing according to the image information. Further, the line (b) shows the path from when the sheet pn is sent from the optional sheet feeding section 20 by the sheet feeding roller 21 to when the image is transferred from the photosensitive drum 2a at the transfer section 6. Further, the line (c) shows the path from the position of the delivery roller 19 immediately before the earliest sheet pm is introduced into the re-feed path 9 to the transfer section 6 via the re-feed path 9.

First, in lines (a) and (b), when the exposure of the image corresponding to the sheet pn newly fed from the option sheet feeder 20 to the photosensitive drum 2a is completed, the sheet pn is pn1. In the position. Further, the exposure start timing is set based on the detection of the leading edge of the sheet by the sensor S2 located immediately before the transport roller 9c and after a predetermined time has elapsed from this detection.

A series of image writing processes from the detection of the sheet by the sensor S2 to the end of the exposure of the photosensitive drum 2a are individually controlled and controlled for each sheet, but the image writing process for a plurality of continuous sheets is performed. Since it is not preferable to perform the operations in parallel because the control becomes complicated, the printer is generally configured to perform the operations sequentially for each sheet.

If the earliest sheet pm of the already fed sheets pn1 exceeds the position of the sensor S2, the process for the sheet pm must be started before the image writing process for the sheet pn1 is completed. Since it must be done, normal control cannot handle it. Therefore, the paper p
m is the distance X between the sensor S2 and the exposure position Z with respect to the sheet pn.
It is necessary to be positioned one position before, and the safety distance X2 is added to this, so that the paper pm is located downstream of the position pm1 which is downstream of the paper pn1 in the paper feeding direction by X1 + X2 = X. When set, it is possible to avoid not only the overlapping of the sheets but also the overlapping of the image writing processes in terms of time.

The position of the sensor S2 can be set at any position as long as it is upstream of the exposure position Z in the paper transport direction, but the distance X must be set to be equal to or larger than the allowable minimum value of the interval between the paper pn and the paper pm. . However, in the double-sided mode, the interval between the sheets fed from the optional sheet feeder 20 is such that the preceding sheet reaches the roller 19 of the duplex unit 10 and the succeeding sheet is the driving roller 18a.
Is set so that it reaches the sheet, but after the image formation on the first side pm
Switchback path 1 again after finishing the image formation on the second surface
The distance X is set to be smaller than the interval between the sheets fed from the optional sheet feeder 20 because the sheet is not conveyed to the sheet feeder 7.

In order to secure the distance X, it is necessary to determine whether to feed the optional sheet from the optional sheet feeding section 20 before a new sheet is fed. Therefore, the determination point is the sheet pm1. Paper pm returned from the position of at least the distance A to the paper feed start position pn of the paper pn1
Position. The position of the sheet of paper pm is obtained by counting the time from when the position of the sheet of paper pm is detected by the discharge sensor S3 of FIG.

If the sheet pn is the sheet pn 'fed from another sheet feeding section, for example, the sheet feeding cassette 3a indicated by a virtual line by the sheet feeding roller 4a, the determination point of the sheet pm is the sheet pm1. The position is the position of the sheet pm 'indicated by an imaginary line, which is returned by the distance B from the position to the sheet feeding start position pn' of the sheet pn1. The position of the sheet pm 'is set to the sheet p after it is detected by the discharge sensor S3.
It is obtained by counting the time to reach the position of m '. As described above, the determination point varies depending on which sheet feeding unit the sheet is fed from, but may be selectively set according to the selection signal of the sheet feeding unit.

Further, as shown in FIG. 3, even if the paper feed unit is the same as the optional paper feed unit 20, if the paper size becomes larger than pn by pn ", the paper finishes writing the image pn1". The distance from the position to the feeding start position is C
And becomes larger than B. Therefore, the paper pn
It is necessary to set the position of the large-size paper pm ″, which has a positional relationship without overlapping with 1 ″, as the determination point. This determination point is also obtained by counting the time when the sheet pm ″ reaches the pm ″ position after being detected by the discharge sensor S3. In this way, the timing detection points for preventing the overlap also differ depending on the paper size. In the double-sided mode, the discharge sensor S3 detects the trailing edge of the sheet, and the arrival of the sheet at the determination point is detected by counting the time from the detection of the trailing edge.

Reference numeral 40 in FIG. 1 is a main body of the original image reading apparatus, in which an image reading unit called IRU is arranged at substantially the center.
Includes an image reading element such as a CCD. Reference numeral 41 is a document feed tray, which is a feed roller 45 and a registration roller 4
A document is supplied to the IRU via the document 6. IRU
The document whose image has been read in is sent to the switchback unit SB. The reading device 40 is provided with a re-feeding path 58 in which conveying rollers 53, 54, 55, 56 are arranged for re-feeding the original sent from the switchback unit SB toward the registration roller 46. ing. The switchback section SB is provided with a switching claw 57 between a transport roller 49 for receiving a document sent from the IRU and a discharge roller 50 for discharging the document to a discharge tray 60. It is configured to select whether the sheet is discharged toward the sheet discharge tray 60 or is discharged toward the switchback portion SB via the transport roller 51 that can rotate in the forward and reverse directions. Reference numeral 52 is a transport roller of the switchback unit SB that can rotate in the forward and reverse directions, and W1 is a document reversal point.

The outline of the main operation of the document image reading device 40 is as follows. In the single-sided mode, the switching claw 57 is set at a position for guiding the delivered document to the sheet discharge tray 60.
In this state, the document is fed from the document feed tray 41 at a necessary timing. The fed document is fed by the registration roller 46 so that the IRU matches the image reading timing. Then, after that, the sheet is discharged face down to the sheet discharge tray 60, that is, the image surface is directed downward by the guide of the switching claw 57.

Next, in the double-sided mode, the switching claw 57 is switched to a position for guiding the original carried in the switchback section SB to the side of the re-feeding path 58, and the conveying roller 52 is re-fed by the switching claw 57. The document guided to the path 58 side is transported to the switchback unit SB, and the document sent from the switchback unit SB is transported to the re-feeding route 58. Therefore, after the image is read, the original that is carried into the switchback unit SB and guided by the switching claw 57 to the refeed path 58 is sent to the switchback unit SB by the conveyance roller 52. When the trailing edge of the sheet reaches the reversal point W1, the transport roller 52 rotates in the reverse direction, and the document is
It is sent to the sheet re-feeding path 58 of the main body 40. The original reaches the registration roller 46 again through the re-feeding path 58, the registration is adjusted, the image on the second side of the original is read by the IRU, the original passes through the conveyance roller 49, and the switching claw 57 switches the original. The document can be switched to a position where it is guided to the SB and the document sent from the switchback section SB is guided to the discharge tray 60.

When the trailing edge of the original reaches the reversal point W2,
The transport rollers 51 and 52 rotate in reverse, the document is guided to the paper discharge roller 50 by the switching claw 57, and is discharged through the paper discharge roller 50 to the paper discharge tray 60 with the first surface of the document facing downward. . The above is the case of reading an image of one original, but when performing the image reading of a plurality of originals in the double-sided mode, the original circulation from the registration roller 46 to the registration roller 46 through the sheet re-feeding path 58. Throughput can be improved by incorporating a plurality of originals in a path and reading an image, and the throughput increases as the number of originals included increases.

In the double-sided mode, the document back side image detecting unit S provided on the downstream side of the paper feed roller 45 is provided.
It is selected when the back side image of the document is detected by the IRU. FIG. 4 shows a paper sheet P for double-sided copying.
It is a schematic diagram which shows the conveyance state of n. In the figure, a is a paper feed path and b is a circulation path. Also, (a) → (b) → (c)
The sheet Pn is transported in the order of → (d) → (e). The semicircle number on the upper and lower surfaces of the sheet Pn indicates that the number indicating the page number of the original is copied on the surface. Further, as shown in the figure, the paper Pn is circulated and conveyed in the direction of the arrow. In this example, up to four sheets of paper Pn can be stored in the paper feed path a and the circulation path b.

(A) shows a state in which the original page surface is copied on the first fed sheet P ₁ and the next sheet P ₂ is fed. (B) shows the original page surface with respect to the first fed paper sheet P ₁ , the original page surface with respect to the next fed paper sheet P ₂ , and the next fed paper sheet P ₃ . A state is shown in which the page of the original is copied and the next paper P ₄ is being fed. Further, the sheets P ₁ and P ₂ are conveyed on the circulation path b at this stage.

In (c), the original page surface is copied onto the fourth fed sheet P ₄ , the sheets P ₂ and P ₃ are conveyed on the circulation path b, and are fed first. The state in which the sheet P ₁ is conveyed again from the circulation path b to the paper feed path a is shown. As is clear from the figure, the above (a),
In each of the steps (b) and (c), the fed paper P
_The pages of the original are copied to the front sides of ₁ , P ₂ , P ₃ , and P ₄ , and the sheet P _{1 that} is subsequently re-fed is reversed and this time, The back side is conveyed as a copy side.

(D) shows a state in which the original page is copied on the back side of the sheet P ₁ and is ejected in the direction indicated by the arrow. Further, the paper P ₂ is re-fed and the papers P ₃ and P
Reference numeral ₄ indicates a state of being conveyed on the circulation path b.
In (e), the paper P _{1 that} has undergone double-sided copying (original, page-side copying) is ejected onto the ejection tray, and the paper P _{2 that} has also undergone double-sided copying (original, page-side copying) is being ejected. The original page is being copied on the back surface of the paper P ₃ , and the paper P ₄ is being conveyed on the circulation path b.

In each of the above steps (a) to (e),
While each of the papers P ₁ to P ₄ is being conveyed on the paper feed path a and the circulation path b, the feeding of the next paper P ₅ (not shown) is stopped, and the paper P ₄ is regenerated. After the paper is fed and the original page is copied on the back side, the process returns to step (a) again, and the next paper P ₅ is fed. Figure 5
6 is a flowchart showing control of the switchback unit SB in the document reading device. First, it is detected whether the original is a double-sided original (S1). If it is not a two-sided original (S
If No in 1), the switching claw 57 guides the document to the paper discharge path (S2). If it is a two-sided original (S1
In the case of Yes), the document is guided to the switchback section SB by the switching claw 57 (S3). Then, when the leading edge of the document is detected by the paper sensor PS3 (S4), the transport roller 51 is rotated forward (S5). Then, it is detected whether or not the leading edge of the document has reached the position of the reversal point W1 (S6). When the leading edge of the document reaches the position of W1 (Yes in S6), the transport roller 52 is rotated forward (S7).

Next, it is judged whether or not the original is discharged (S8). When ejecting the document (Yes in S8
In the case of s), it is further detected whether or not the trailing edge of the document has reached the position of the reversal point W2 (S9). Then, if it reaches (Yes in S9),
The transport rollers 51 and 52 are rotated in reverse (S10). Then, it is detected whether or not the leading edge of the document has reached the position of the reversal point W2 (S11). Then, when it has reached (Yes in S11), the transport rollers 51 and 52 are stopped (S12).

When the document is not discharged (No in S8)
In the case of), it is further detected whether or not the trailing edge of the document has reached the position of the reversal point W1 (S13). If it has arrived (Yes in S13), the transport roller 52 is rotated in the reverse direction (S14). Subsequently, it is detected whether or not the leading edge of the document has reached the position of the reversal point W1 (S15). If it has arrived (Yes in S15), the transport rollers 51 and 52 are stopped (S16).

FIG. 6 is a flow chart showing the document image reading timing control and the document feed control. Regarding the image reading control, first, it is detected whether or not the paper sensor PS2 is turned on (S21). If it is turned on (Yes in S21), the transport roller 46
Is stopped (S22). Next, a subroutine (see FIG. 7) for detecting the front and back sides of the document is executed (S23). Then, a subroutine for selecting the memory writing method (see FIG. 8) is executed (S2).
4). Further, a subroutine (see FIG. 9) for preparing the memory writing is executed (S25).

When it is confirmed whether or not the image reading is on standby (Yes in S26), the transport roller 46 is rotated (S27). Then, after confirming the end of the delay time in the circuit of the image reading unit IRU (Yes in S28), reading of the original image is started (S29). Then, when the necessary image area to be read is finished (Yes in S30), the reading of the image is finished (S31). Then, it is confirmed whether or not the copying operation performed corresponding to the image reading is completed (S32).

Regarding the document feeding control, first, it is judged whether or not the document feeding is performed (S41). When feeding the document (Yes in S41), the transport roller 45 is used.
Is rotated, and a paper feed flag indicating that the first side (one page) of the original is fed is turned on (S42). Then, it is detected whether or not the paper sensor PS2 is turned on (S43). When it is turned on (S43
If Yes, the timing of determining whether or not the next original can be fed is determined (S44). If the timing is possible (Yes in S44), further feeding is performed. The presence / absence of a document to be printed is detected (S45).

FIG. 7 is a flow chart showing a process for detecting the front and back sides of a document, and the paper sensors PS1 and P1.
The front side and the back side are discriminated by the combination of S2, and the respective reading modes are set. First, the paper sensor PS2
It is detected whether or not is turned on (S51). If it is turned on (Yes in S51), subsequently, it is detected whether or not the paper sensor PS1 is turned on (S52). When the paper sensor PS1 is turned on (Yes in S52), the front surface of the document is read (S5).
3). When the paper sensor PS1 is not turned on (No in S52), it is further detected whether or not the paper sensor PS5 is turned on (S54). When the paper sensor PS5 is turned on (Yes in S54), the back side of the document is read (S55).

FIG. 8 is a flowchart showing a process for selecting the memory writing method. In this copying apparatus, the image data read by the image reading unit IRU can be stored in the first and second memories. As for the capacity of such a memory, one memory can store image data for at least one page of the original. That is, in the flowchart shown in FIG.
The processing for determining which memory is selected when storing (transferring) the image data read by the IRU in the first and second memories is shown.

First, the numbers of originals and sheets to be stored in the original conveying circulation path and the sheet conveying circulation path (hereinafter referred to as "paths") are determined. This decision is made based on the document size or the paper size. Further, in this flowchart, the number of documents and sheets to be stored is shown as three or two. Therefore, it is judged whether or not the number of sheets accommodated in the route is three (S61), and if not three (S61).
In the case of No), the write mode selection subroutine when the number of sheets accommodated in the path is two is executed (S62).

Next, when the number of sheets accommodated in the route is three (Yes in S61), the number of units is subsequently set to 1
It is determined whether or not (S63). Here, the copy number means the number of copies for the same screen. When the number is 1 (Yes in S63)
, The image data is continuously written twice in each of the two memories (S64). Such a memory writing mode is referred to as a memory writing mode (1). If the number of copies is not 1 (No in S63), the two-sided document reading / two-sided copy mode (hereinafter, both / both mode) is further performed.
It is determined whether or not (S65).

In the case of both / both modes (Yes in S65), the image data of the front side and the back side of the document is written in another memory (S66). Such a memory writing mode is referred to as a memory writing mode (2). If it is not in the double / double mode (No in S65), it is further determined whether or not the single-sided original reading / single-sided copy mode (hereinafter, single / single mode) is set (S6).
7). When in single / single mode (Yes in S67)
In the case of), only one memory is written (S6).
8). Such a memory write mode is called a memory write mode
(3) If the single / single mode is not set (No in S67), that is, the single-sided original reading / double-sided copying mode, or the double-sided original reading / single-sided copying mode, the data is written alternately in two memories ( S6
9). Such a memory write mode is called a memory write mode
(4)

As described above, each memory writing mode
(1) to (4) are determined. It should be noted that the above-described setting of the number of copies and the document reading mode / copy mode is performed through the operation panel shown in FIG. Further, the above processing is performed based on the schematic diagrams showing the relationship between the document reading and the corresponding copy in FIGS. 23 to 26. Furthermore, three documents are placed in the paper transport circulation path in the document transport circulation path.
If a sheet of paper is to be stored, or if the original has two
In the case where three sheets are accommodated in the latter and the latter case, it is naturally conceivable that the sheets are accommodated in each circulation path and the number of sheets is different due to conversion of magnification or the like. However, similar processing is performed based on FIGS. it can. Further, there are various conceivable ways of determining the write mode to the memory other than this flowchart, which will be described with reference to FIGS.

FIG. 9 is a flow chart showing the processing for preparing the memory writing. That is, it is a flowchart for specifically switching the memory to be written before starting reading. First, each memory write mode (1) determined by the flowchart shown in FIG.
(4) is discriminated (S70). Then, each processing is performed for each determined mode.

In the case of the memory writing mode (1), the count value of the memory counter is confirmed (S7).
1). The memory counter is a counter for counting the number of writings to the memory. When the count value is 0 or 1, the first memory is selected (S7
2), the counter is incremented (S73). If the count value is 2, the second memory is selected (S74), and the counter is incremented (S74).
75). Further, when the count value is 3, the second memory is similarly selected (S76) and the counter is cleared (S77). That is, by the processing of S72 to S77, the first memory and the second memory are switched every time writing is performed twice while incrementing and clearing the memory counter.

In the memory write mode (2), similarly, the value of the memory counter is confirmed, and if the count value is 0 (Yes in S78), the first memory is selected. (S79), and the counter is incremented (S80). When the count value is not 0 (No in S78), the second memory is selected (S81) and the counter is cleared (S82).

In the memory writing mode (3), the first memory is simply selected (S83). Further, in the case of the memory writing mode (4), the front and back surfaces of the document are checked, and when the front surface is the front surface (Yes in S84), the first memory is selected (S85), and the front surface is selected. If not (No in S84), the second memory is selected (S86).

FIG. 10 is a top view showing the operation panel of the copying apparatus according to the present invention. This operation panel includes a button input section 100 and a display section 101. The button input section 100 is provided with various operation buttons such as a number setting button 102, a copy mode selection button 103, and an original selection button 104. ing. The display unit 101 also displays the paper size, paper feed port, number of copies, magnification, toner empty,
Paper empty, jam, trouble, etc. are displayed.

FIG. 11 is a block diagram showing the control circuit of the copying apparatus according to the present invention. This control circuit is CPU1
The CPU 4 is mainly composed of four CPUs. C
The PU 1 analyzes the signals sent from the switches provided on the operation panel and the numeric keypad or the data sent by the communication, displays the data, and executes the processing of sending the input data. The CPU 2 is an optical conversion element (CC
Image data from D) is input, shading correction,
In addition to normal image processing such as scaling and dither processing,
And controlling to output the data to the laser modulation conversion unit via either one of the two second memories. It also controls document feeding such as feeding, reversing, and ejecting documents.

The CPU 3 executes a control functioning as a coordinator of the entire apparatus, and adjusts mutual timings and determines an operation mode. The CPU 4 controls an image forming system and an optical system, and executes control of printing-related operations such as charging control of the photosensitive drum, writing of image data, toner developing operation, and paper feeding control. 12
3 is a flowchart showing the operation of the CPU 1. First, initialization is performed (S90), and then an internal timer is started (S91). Then, input control is performed (S92). Here, operations such as the number of copies, magnification, double-sided document reading, double-sided copying, etc. are controlled according to input signals from switches on the operation panel or a group of ten keys. Subsequently, control (S93) for causing the display unit 101 on the operation panel to display the setting contents and the like is performed. In addition, if trouble data is received from another CPU through communication, a corresponding display is also performed. Furthermore,
When other control is performed (S94) and the end of the internal timer is confirmed (Yes in S95),
It returns to S91 again and repeats the above processing. In addition to this, communication with other CPUs is performed by interrupt control (S
96).

FIG. 13 is a flow chart showing the operation of the CPU 2. First, initial setting is performed (S11
1) Next, the internal timer is started (S11).
2). Subsequently, image data is input (S11
3), image processing is performed (S114). Then, the image data is output to the laser converter (S115). Further, when other control is performed (S116) and the end of the internal timer is confirmed (S117), S112 is executed again.
Return to and repeat the above process. Further, similarly to the case of the CPU 1, communication with other CPUs is performed by interrupt control (S118).

FIG. 14 is a flow chart showing the operation of the CPU 4. First, initial setting is performed (S12
0), then the internal timer is started (S12).
1). Subsequently, development and transfer system control is performed (S12).
2). Here, control of each process of charging → exposure → developing → transfer is performed while the photosensitive drum makes one rotation. That is,
The surface of the photoconductor drum is charged to a uniform potential by the charging charger, and the electrostatic latent image is formed by irradiating laser light to expose the latent image. Further, a bias voltage is applied by the developing device to supply toner to perform reversal development. Then, the obtained toner image is transferred onto a sheet by a transfer charger.

Next, the paper feed system is controlled (S12).
3). Here, control is performed such as feeding a sheet from a sheet feeding cassette, starting a timing roller for aligning the leading edge of the toner image with the leading edge of the sheet, and transporting the sheet after the transfer is completed to the fixing unit. Further, the fixing system is controlled (S12).
4). Here, the fixing of the toner image transferred on the paper by thermocompression bonding, the temperature control of the fixing roller, the discharge of the paper after the fixing, and the like are performed. Then, the print processing unit is controlled (S125). That is, a signal to the laser drive circuit,
Control of memory switching, paper feed and exposure timing, etc. is performed. Furthermore, other processing (processing at the time of trouble, other processing associated with print operation, etc.) is performed (S12).
6) If it is confirmed that the internal timer has ended (Yes in S127), the process returns to S121 and the above processes are repeated. Further, as in the case of the CPU 1, another C
Communication with the PU is performed by interrupt control (S128).

FIG. 15 is a flow chart showing the operation of the CPU 3. The CPU 3 operates each processing unit (CP
U1, CPU2, CPU4) are started and stopped, and operation modes are set. First, initial setting is performed (S1
30) Next, the internal timer is started (S13).
1). Subsequently, the input data is analyzed (S132),
Furthermore, the mode and command are set (S13).
3). Then, the output data is set (S1).
34). After that, other processing is performed (S135),
When the end of the internal timer is confirmed (Yes in S136), the process returns to S131 and the above processes are repeated. Also, after checking whether the data input by communication is correctly received,
Analyze the contents. Then, depending on the contents, when there is something to be operated next or when the magnification is changed, etc., the start command and the mode data of the magnification are newly set, and that data is output for communication. Is set in the output area or the like (S137).

FIG. 16 is a flow chart showing the processing for selecting the mode read from the memory. That is, it is a flowchart for determining in what order the memory (first memory or second memory) to be read is selected, which is a subroutine in the processing of the CPU 4 described above. First, it is judged from the size of the paper whether or not three sheets are stored in the path (original circulation path and paper circulation path) (S138). If three sheets are not stored (No in S138), a processing subroutine for storing two sheets in the route is executed (S139).
Also in this subroutine, the processing for setting the read mode from the memory is performed. Also, 3
In the case of storing sheets (Yes in S138),
The CPU 2 communicates with the CPU 2 (IR CPU) to determine which of the memory write modes (see FIG. 8) is selected (S140), and the process proceeds to the next step.

In the case of the memory writing mode (3), that is, the mode in which the image data is written in one of the memories (referred to as the first memory), the single-sided original reading / single-sided copying mode (single / single mode will be described. ) Is determined (S141). Then, in the one-sided / one-sided mode (Yes in S141), the first
A mode for reading from only the memory is set (S14
3). If it is not the one-sided / one-sided mode (No in S141), it is further determined whether or not the number is 3 (S142). Then, when the registered number is 3 (Yes in S142), the mode of reading from only the first memory is set (S143). If the number is not 3 (No in S142), the processing is interrupted and a warning is given (S144), assuming that there is an error in the operation method or some trouble. The process of S144 will be described as an NG process hereinafter. It should be noted that this NG process is set based on the memory read table so as to be an NG process for a mode that cannot be executed.

Next, the memory writing mode (4), that is, 2
If the mode is such that the image data is alternately written to one memory (first memory and second memory), it is determined whether the single-sided copy mode is set (S145). In the case of the single-sided copy mode (Yes in S145), the mode in which data is continuously read every several number of copies is set (S146). Further, it is determined whether or not it is the double-sided document reading (S147), and if it is the double-sided document reading mode (Yes in S147), it is further determined whether or not the number of copies is one (S148). ), If the number is 1 (Yes in S148), NG
Processing is performed (S149).

If the single-sided copy mode is not set (S1
In the case of No in 45), the mode of continuously reading three times is set (S150). Subsequently, it is determined whether or not it is a double-sided document reading (S151),
When not in the double-sided original reading mode (No in S151)
If the number is 1 (S152), and if the number is 1 (Yes in S152), the NG process is performed (S15).
3).

In the double-sided original reading mode (S
In the case of Yes in 151), it is further determined what the number of units is (S154), and when the number of units is 1, the mode of alternately reading is set (S15).
5). If the number is 2, the NG process is performed (S156). Further, when the number of copies is 3 or more, the state of S150 is maintained.

In the case of the memory writing mode (1), that is, the mode in which the image data is continuously written twice in the two memories, the mode in which the reading is continuously performed by the number of units × 2 times is set. (S157). Subsequently, it is determined whether or not the one-sided original reading / one-sided copy mode (single / single mode) is selected (S158), and if it is this mode (Yes in S158), the process directly returns. If the mode is not in this mode (No in S158), it is further determined whether or not the number is 3 or less (S159), and 3 or less (S159).
If Yes in 159), it is further determined whether or not the single-sided original reading / double-sided copy mode (single / double mode) is selected (S160), and if single / double mode (Yes in S160). ), It is further determined whether or not the number is 2 (S161), and if the number is 2 (Yes in S161),
NG processing is performed (S162). In addition, when the number is not less than 3 and is not in the single / both mode, and the number is not 2 (S
159, S160, No in each step of S161
In the case of), it is judged whether the mode is the double-sided original reading / double-sided copy mode (both / both modes) (S16).
3) In the case of both / both modes, it is further determined whether the number is 2 or 3 (S164). When the number of units is 2 or 3 (Yes in S164), the mode of continuously reading three times each is set (S).
165).

Further, when the mode is not both / both modes and the register number is not 2 or 3 (No in each step of S163 and S164), it is further judged whether the register number is 1 or not. (S166) If it is 1 (Yes in S166), the mode is set such that the first reading is performed once and then the second reading is performed twice (S167). The number is 1
If not (No in S166), the process returns.

In the memory writing mode (2), that is, when the image data of the front side and the back side of the original is written in the first and second separate memories, the double-sided original reading / double-sided copying mode (both / both modes) ) Is determined (S
168), if both / both modes (Yes in S168), a mode is set in which the front side image data is read from the first memory and the back side image data is read from the second memory (S169). If the mode is not the both / both mode (No in S168), the NG process is performed (S170).

In addition, in addition, three sheets in the original circulation path are two sheets in the paper circulation path, and further two sheets in the original circulation path are three in the paper circulation path.
It may be possible to store the sheets, but in such a case,
It is possible to process in the same manner. FIG. 17 is a flowchart showing a process for actually switching the memory to be read based on the read mode from the selected memory, which is also a subroutine in the process of the CPU 4. First, it is determined whether or not copying is in progress (S180). If copying is not in progress (No in S181), both the first and second memories are cleared (S181). If copying is in progress (Yes in S180), the read mode from the selected memory is determined (S182), and the following processing is performed for each mode.

When the mode for reading only from the first memory is selected, the paper sensor S1 is turned on (OFF).
(Change point to ON)) is determined (S183). Then, when the paper sensor S1 is at the ON edge (Yes in S183), the first memory is selected (S184). Further, when the mode of continuously reading every number of copies is selected, it is similarly determined whether or not the paper sensor S1 is the ON edge (S185), and the count value (number of sheets) of the counter is set as the number of copies. Then, the processing for switching the selected memory (switching of selected memory → clearing of counter → incrementing of counter) is performed (S186). Also, 3
When the mode to read continuously each time is selected,
Similarly, it is determined whether or not the paper sensor S1 is an ON edge (S187), and when the count value of the counter reaches 3, a process for switching the memory is performed (S1).
88).

Further, when the mode of continuously reading each number of copies × 2 times is selected, the paper sensor S1 is also turned off.
It is determined whether or not it is the N edge (S189), and when the count value of the counter becomes the number of units x 2, a process for switching the memory is performed (S190). Also, the first
When the mode for reading the image data of the front side from the memory of No. 1 and the image data of the back side from the second memory is selected, it is similarly judged whether or not the paper sensor S1 is the ON edge (S191), and subsequently, Then, it is determined whether the copy is on the front surface or the back surface of the paper (S192). The determination method here is to count the time after the first sheet turns on the sheet sensor S1,
The time required to reach the sheet sensor S1 again through the circulation path is stored and compared, and it is determined whether the timing is the front side copy timing or the back side copy timing. If it is a copy to the front side (Yes in S192,
In the case of s), it is switched to the first memory, and in the case of copying to the back side (in the case of No in S192), it is switched to the second memory (S193, S194).

When the mode for reading once at the first time and twice at the second time is selected, the paper sensor S
It is determined whether 1 is an ON edge (S19).
5), if it is an ON edge (Yes in S195)
In the case of), the process of switching the first memory / second memory is performed only once at first (S196 to S20).
0). That is, it is determined whether the count value of the counter is 0 (S196), and if it is 0 (Yes in S196), the memory is switched to the first memory (S197) and the counter is incremented. (S2
00). When the count value of the counter is not 0 (No in S196), it is further determined whether or not the count value is 1 (S198), and when it is 1 (Yes in S198). Is switched to the second memory (S199). If the count value is not 1 (No in S198),
The process of S190 is performed.

Next, the method of feeding the original will be described.
FIG. 18 is a table showing a method 1 of controlling the feeding of a document in the case where each of the document circulation path and the paper circulation path accommodates three sheets of paper. That is, the sheet feeding method is shown separately for the number of copies and the single-sided or double-sided original reading / single-sided or double-sided copy mode. For example, when the number of sets is 1, sheet feeding is performed for each set number in the one-sided / single mode, and continuous sheet feeding is performed in the one-sided / both mode. In both / single mode, the number of units x 2
Paper feeding is performed for each sheet, and in the both / both mode, after three sheets have been fed, paper feeding corresponding to three times is suspended. Also,
When the number of copies is 2, in the one-sided / single mode, the paper is fed for every number of copies as in the case of the one for the number of copies. After feeding one sheet, it takes one rest, after feeding one more sheet, takes two rests, after feeding one more sheet, takes one rest, and after feeding one more sheet, takes one rest.
Also, in both / single mode, as in the case of the register number 1, the register number ×
Paper is fed every 2 sheets, but in both / both mode, it will be rested once after feeding 1 sheet, rested 4 times after feeding 1 sheet, and rested 4 times after feeding 1 more sheet. .

Further, when the number of copies is 3, the one-side / one-side mode and the two-sides / one-side mode are the same as the case where the number of registrations is one. I will take a rest, and then take two rests after feeding one sheet. In the both / both mode, the paper feed is performed by the number of registrations × 2-b, where the number of registrations / 3 = a ... b. If the number is 4,
The one-sided / one-sided mode and the both-sided / one-sided mode are the same as the case of the numeral unit 1;
If b ≠ 0, then a ...
After feeding two sheets, rest two times, and then feed one more sheet (number of copies x 2
-B-4) Rest, feed one more sheet, rest twice, feed one more sheet, then (number of copies + b x 2-7) rest, one more
After feeding two sheets, rest two times, and then feed one more sheet (number of copies x 2
-B-1) You will have to take a rest. Also, if b = 0, one sheet is fed for each number of units × 2, then two rests are taken, and further 1
After feeding the sheets (number of copies × 2-b-4), the printer has to rest.
Then, in both / both modes, the same processing as in the case of the numeral unit 3 is performed. (Note that description for the case where the number of copies is 5 or more is omitted.) FIG. 19 is a document feeding control when two sheets of paper (document and sheet) are accommodated in the document circulation path and the paper circulation path, respectively. 9 is a table showing method 2. As shown in the table, when the number of copies is 1, in the one-sided / single mode, the paper is fed for each number of sets, and in the one-sided / both mode, continuous paper feeding is performed. Further, in the both / single mode, two sheets are rested after feeding two sheets, and in the both / both mode, two sheets are rested after feeding two sheets. Further, when the number of copies is 2, in the one-side / one-side mode, the same number of sheets is fed, but in the one-side / two-mode, the sheets are fed every two sheets. Further, in the both / single mode, the number of sheets is fed every 2 sheets, and in the both / both mode, the number of sheets is fed every 2 sheets.

Further, when the number of copies is 3, the same number of sheets is fed in the one-sided / one-side mode, but in the one-sided / two-sided mode, the number of sheets is divided by 2 = a = b. After taking one rest, after feeding one more sheet (number of copies × 2-3-b), resting once after feeding one more sheet, and after feeding one more sheet (number of × 2−2) 3+
b) You will have to take a break. In both / single mode, the number of units x
Paper is fed every two sheets, and in both / both mode, the same number of units divided by 2
= A ... b, one sheet is fed (numerical value × 2-1−b) and then one sheet is fed (numerical value × 2-1 + b) times. (Note that the description for the case where the number of copies is 4 or more is omitted.) FIGS. 20, 21, and 22 show which sheet is used to transfer the original image when the reading and copying modes are changed. FIG. 20 is a schematic diagram showing an image flow when an image of a single-sided original is copied onto both sides of a sheet. FIG. 21 is a schematic diagram showing an image flow when an image of a double-sided original is copied onto one side of a sheet. Reference numeral 22 is a schematic diagram showing the flow of images when copying an image of a double-sided original onto both sides of a sheet. In the figure, the arrows indicate the specific flow of images, the upper row shows the case where the number of copy copies is 1, and the lower row shows the case where the number of copy copies is 2. Further, front and back displays on the manuscript and the paper indicate the front and back faces, respectively, and the number display indicates the respective feeding order.

For example, in FIG. 20, six single-sided originals are fed in the order of 1 → 2 → 3 → 4 → 5 → 6, and three sheets of paper are 1 (front) → 2 (front) → 1 ( Back) → 3 (front) → 2 (back)
→ Paper is fed in the order of 3 (reverse side) while reversing the front and back sides. Therefore, the image of the first fed single-sided original is formed on the front surface of the first fed sheet. The image of the second-side fed single-sided original is formed on the back side of the first sheet fed first. Further, the image of the one-sided original fed third is formed on the surface of the sheet of the second fed, and the image of the single-sided original fed fourth is the image of the one fed second. Formed on the back side of the paper. Also, the image of the single-sided original fed fifth is formed on the front surface of the sheet of the third fed, and the image of the single-sided original fed sixth is the image of the single-sided original fed third. Formed on the back side of the paper. The description of FIGS. 21 and 22 is omitted.

23 to 31 are schematic diagrams showing a method of controlling the feeding of the original and the feeding of the sheet and the control of the image memory. 23 is a single-sided original reading / single-sided copying mode, FIG. 24 is a single-sided original reading / double-sided copying mode, FIG. 25 is a double-sided original reading / single-sided copying mode, and FIG. 26 is a double-sided original reading / double-sided copying mode. 9 illustrates a paper feed control method for a sheet and a control method for an image memory.

For example, double-sided original reading /
In the double-sided copy mode, the feeding of originals and sheets and the control of the image memory are performed as follows. First, how to read this schematic diagram will be described. In the uppermost stage, when the number of copies is 1, the lower stage is when the number of copies is 2, the lower stage is when the number of copies is 3, and in the lowermost stage, the manuscript, the paper when the number of copies is 4, Each correspondence of the memory is shown respectively. Further, the opposed and delimited rectangles are shown such that a document is fed on the upper side and paper is fed on the lower side in order from the left (note that the number indicates the number of pages). Further, the step provided on the display of the original and the sheet indicates that the upper part uses the front side and the lower part uses the back side. Further, "," shown between the opposite rectangles respectively indicate the first memory and the second memory. Further, the arrow indicates that the document image is transferred to the opposing paper sheet via the first memory or the second memory.

When the number of copies is 1, the originals of the first, third, and fifth pages, which are the pages on the front side, are sequentially fed to the reading unit. After that, pages of pages 2, 4, and 6 which are pages on the back side are sequentially fed to the image forming unit. Correspondingly, paper is also fed in the same manner. In this case, the original images of the first and third pages are temporarily stored in the first memory and then transferred to the opposing paper by a printing device (not shown). Further, the original image of the fifth page is temporarily stored in the second memory and then transferred to a sheet of paper which faces the same. Then, the front and back of the original are reversed, and the original image of the second page, which is the back of one page, is temporarily stored in the second memory and then transferred to the opposing paper. In this case, the front and back surfaces of the paper are also inverted, and the original image of the second page is transferred to the back surface of the paper on which the original image of the first page has been transferred. Thereafter, similarly, the original images of the fourth and sixth pages are once stored in the first memory and then transferred to the facing paper.

As described above, regarding the memory for storing the original image, the same memory is stored twice, as in the first memory → first memory → second memory → second memory → first memory → first memory. However, the order of using each memory is not particularly limited. When the number of copies is 2, the first memory and the second memory are alternately used twice each. It should be noted that the broken line in the figure indicates a state in which the document is not read and the document is on standby. When the number of copies is 3, only the first memory is used in the figure, but in this case as well, the method of using the memory is not particularly limited. When the number of copies is 4, the first memory and the second memory are used alternately. 23, 24,
Description of 25 is omitted.

FIGS. 27, 28 and 29 show the case where only two sheets of paper (original and paper) enter the paper path, respectively. FIG. 27 shows the single-sided original reading / duplex copy mode, and FIG. In the original reading / single-sided copy mode, FIG. 29 shows a method of controlling the feeding of originals and sheets and a method of controlling the image memory in the double-sided original reading / double-sided copy mode. Further, FIGS. 30 and 31 both show the double-sided original reading / double-sided copy mode.
0 indicates that only three originals are in the original circulation path and only two sheets are in the paper circulation path.
When the number of sheets and the number of sheets in the sheet circulation path are only three, the method for controlling the feeding of the original and the sheet and the method for feeding the image memory are used. Note that description of these FIGS. 27 to 31 is omitted.

FIG. 32 shows a case where three sheets of paper (document and paper) are accommodated in the document circulation path and the paper circulation path, respectively.
3 is a table showing how to use the memory according to the number of copies and the mode when two papers (documents and papers) are accommodated in each circulation path. (1) uses only the first memory, (2) uses the first memory and the second memory alternately, and (3) uses the first memory and the second memory twice, respectively. Further, (4) shows the case where the front and back of the original are read using another memory, and (5) shows the case where the front and the back of the paper are written using another memory. And, in the figure, ○ indicates that it can be used, and × indicates that it cannot be used.

The relationship between reading into the memory and writing from the memory is as follows.
For example, in the case of storing three sheets of paper in the paper circulation path and alternately reading to the first memory and the second memory, when copying two or more copies in the single / both mode, the first memory From the second memory, and three times from the second memory. In addition, when copying two or more copies in the both / single mode, each copy is written. Furthermore, when copying one copy in both / both modes, writing is alternately performed from the first memory and the second memory. In addition, when copying 3 or more copies, copy 3 from the first memory.
Times, it will be written from the second memory three times.

On the other hand, in the case of reading into the first memory and the second memory twice each, when one copy is made in the single / both mode, writing from the first memory, resting once, then writing from the second memory, Further, the data is written from the first memory twice, and subsequently, is written from the second memory twice. Further, when copying three copies, the data is written from the first memory six times and then from the second memory six times.

Further, when copying one copy in the both / single mode, writing from the first memory, resting twice, writing from the second memory, then writing from the second memory, and then twice from the first memory. It will be written out and then written out from the second memory twice. Also, when copying a few copies, the number is written from the first memory x 2 times and then from the second memory, x 2 times.

Further, when copying one copy in both / both modes, the first memory and the second memory are written twice, and when copying two to three copies, three copies are made from the first memory and two times. It will be written out from the memory three times.

[0091]

As described above, according to the present invention, the document circulation path capable of accommodating a predetermined number of documents is provided, and the reversed document is re-supplied to the reading section in order through the circulation path. The reading efficiency of a double-sided original becomes extremely good. Further, similarly, a paper circulation path capable of accommodating a predetermined number of paper sheets is provided, and the paper sheets can be supplied to the image forming unit in response to the document reading operation. Therefore, double-sided copying efficiency is remarkably improved.

Further, regarding whether to use the double-sided reading mode or the single-sided reading mode, since the presence of the image on the back side of the document is automatically detected and the double-sided reading mode is selected, there is no need to set the mode, which is very convenient. Will get better. Further, by using a memory for at least two screens, it is possible to flexibly deal with copy conditions such as double-sided originals or single-sided originals, double-sided copying, single-sided copying, and the number of copies. Therefore, it is possible to remarkably improve the copying function without incurring a cost increase factor in terms of memory components.

[Brief description of drawings]

FIG. 1 is a front sectional view showing a copying apparatus according to the present invention.

FIG. 2 is a schematic diagram showing a fed sheet and a positional relationship after the sheet is re-fed.

FIG. 3 is a schematic diagram showing the positional relationship between the fed paper and the paper after re-feeding.

FIG. 4 is a schematic diagram illustrating a sheet conveyance state during double-sided copying.

FIG. 5 is a flowchart showing control of a switchback unit in the document reading apparatus.

FIG. 6 is a flowchart showing timing control of document image reading and document feed control of a document.

FIG. 7 is a flowchart showing a process for detecting the front and back of a document.

FIG. 8 is a flowchart showing a process for selecting a memory writing method.

FIG. 9 is a flowchart showing a process for preparing memory writing.

FIG. 10 is a top view showing an operation panel of the copying apparatus according to the present invention.

FIG. 11 is a block diagram showing a control circuit of the copying apparatus according to the present invention.

FIG. 12 is a flowchart showing an operation of the CPU 1.

FIG. 13 is a flowchart showing an operation of the CPU 2.

FIG. 14 is a flowchart showing an operation of the CPU 4.

FIG. 15 is a flowchart showing an operation of the CPU 3.

FIG. 16 is a flowchart showing a process for selecting a read mode from a memory.

FIG. 17 is a flowchart showing a process for actually switching the memory to be read based on the read mode from the selected memory.

FIG. 18 is a table showing a method of controlling the feeding of a document in the case where each of the document circulation path and the paper circulation path accommodates three sheets of paper.

FIG. 19 is a table showing a document feeding control method when two sheets of paper are accommodated in each of the document circulation path and the paper circulation path.

FIG. 20 is a schematic diagram showing a flow of an image when a single-sided original image is copied onto both sides of a sheet.

FIG. 21 is a schematic diagram showing the flow of images when copying an image of a double-sided original onto one side of a sheet.

FIG. 22 is a schematic diagram showing a flow of an image when copying an image of a double-sided original onto both sides of a sheet.

FIG. 23 is a schematic diagram showing a method for controlling the feeding of originals and sheets and a method for controlling the image memory in the single-sided original reading / single-sided copying mode.

FIG. 24 is a schematic diagram showing a method for controlling the feeding of originals and sheets and a method for controlling the image memory in the single-sided original reading / double-sided copy mode.

FIG. 25 is a schematic diagram showing a method for controlling the feeding of a document and a sheet and a method for controlling an image memory in the double-sided document reading / single-sided copy mode.

FIG. 26 is a schematic diagram showing a method of controlling the feeding of originals and sheets and a method of controlling the image memory in the double-sided original reading / double-sided copy mode.

FIG. 27 is a schematic diagram showing a method of controlling the feeding of originals and sheets and a method of controlling the image memory in the single-sided original reading / double-sided copying mode in the case where only two sheets of paper enter the sheet passing path.

FIG. 28 is a schematic diagram showing a method of controlling the feeding of a document and a sheet and a method of controlling an image memory in the double-sided original reading / single-sided copying mode in the case where only two sheets of paper enter the paper path.

FIG. 29 is a schematic diagram showing a method of controlling the feeding of a document and a sheet and a method of controlling an image memory in the double-sided original reading / double-sided copying mode in the case where only two sheets of paper are included in the paper path.

FIG. 30 shows a method for controlling the feeding of originals and sheets, and a method for controlling the image memory in the double-sided original reading / double-sided copy mode in the case where only three sheets enter the original circulation path and only two sheets enter the paper circulation path. It is a schematic diagram.

FIG. 31 shows a method of controlling the feeding of a document and a sheet and a method of controlling an image memory in the two-sided document reading / two-sided copy mode in the case where only two sheets enter the document circulation path and only three sheets enter the paper circulation path. It is a schematic diagram.

FIG. 32 is a table showing how to use the memory according to the number of copies and the mode when three sheets of paper are accommodated in each of the original circulation path and the paper circulation path.

FIG. 33 is a table showing how to use the memory according to the number of copies and the mode when accommodating two sheets of paper in each of the original circulation path and the paper circulation path.

[Explanation of symbols]

 1 Printer main body 2 Image forming unit 17 Switchback path 40 Original image reading device main body 45 Paper feed roller 46 Registration roller 50 Paper discharge roller 57 Switching claw 58 Refeed path IRU Image reading unit SIRU Original backside image detection unit SB Switchback Department

Claims (4)

[Claims] 1. A copying apparatus comprising a document reading unit and an image forming unit capable of forming images on both sides of a sheet, wherein the document reading unit reads a document image, and a document in the document reading unit. A document feeding means for automatically feeding the document, a document discharging means for discharging the read document, a switchback means for switching back the scanned document, a switchback document which is circulated, and the upstream of the document reading means again. Side original recirculation and resupply means, original conveyance direction switching means for switching the conveyance direction so that the original is conveyed to either the original discharge means or the switchback means, and the original for detecting the number of passed originals A copying apparatus comprising: a sheet passing number detecting means; and a control means for controlling a document feeding interval and a number of separated sheets according to a copy mode. 2. The copying apparatus according to claim 1, wherein the document reading unit changes a document reading interval depending on a copy mode. 3. The copying apparatus according to claim 1, wherein the document feeding unit and the document circulation re-feeding unit divide the document into a predetermined number of sheets according to a copy mode and feed the document to the document reading unit. 4. The document supply unit and the document circulation re-supply unit divide the document into predetermined number of sheets according to the number of copies, the number of documents to be circulated, or a combination of the number of copies and the number of documents to be circulated. The copying apparatus according to claim 1, wherein the copying apparatus supplies the original reading means.