JP3254942B2 - Digital copier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital copying machine, and is characterized by a double-sided copying function for printing a copied image on both sides (first and second sides) of a sheet.

[0002]

2. Description of the Related Art In general, double-sided copying is realized by sequentially performing first-side copying for printing on the first side of a sheet and second-side copying for printing on the second side. Therefore, the copying machine is provided with a paper transport mechanism for reversing the paper (cut paper) after the first-side copy and re-feeding the paper to the copy position. If an automatic double-sided document feeder (ADFR) is used together, double-sided copying can be completely automated not only for single-sided originals but also for double-sided originals.

A digital copier equipped with an image memory for storing document images of a predetermined page can copy each document image onto a sheet in a different order from the reading order when copying a large number of documents. it can. Therefore, in this type of copying machine, by using a circulating paper transport mechanism that guides the paper to the copy position without stopping on the way, the transport path length is set to a length that allows circulation of a plurality of papers, Efficient duplex copying is performed.

[0004] That is, the entire required time is shortened by performing the copying of each side collectively for a plurality of sheets without alternately performing the first-side copying and the second-side copying for each sheet. .

FIG. 29 is a schematic diagram showing an example of double-sided copying. In the example shown in the figure, ten single-sided documents D1 to D10, that is, document images for ten pages are separately copied on the front and back of five sheets of paper P1 to P5. The number of sheets in one circulation varies depending on the sheet size. Here, it is set to three. The “page” refers to a processing unit of reading or printing, and has nothing to do with a page number (a so-called page number) in a book or the like.

The images of the originals D1 to D10 are one by one (1
The image data is sequentially read in order (each page) and quantized into digital image data. This image data is sequentially compressed and temporarily stored in the image memory in page units. Then, in parallel with the storage of the image data, image data of a predetermined page is read from the image memory, and a copy image is printed on a sheet.

At this time, ideally, first, the three sheets P1 to P3 are circulated, and the odd-numbered (1, 1)
3rd and 5th) and even-numbered (2nd, 4th and 6th) original images are copied in the order shown in FIG.
The two-sided copying may be performed by circulating the sheets P4 and P5.

However, depending on the relationship between the reading speed and the printing speed (paper transport speed), for example, the feed start timing of the first paper P1 is set to the value corresponding to one page to be copied, as shown in FIG. Even if the setting is made after the reading of the original image is completed, the second sheet P2
In some cases, the reading of the third document D3 may not be in time for the first-side copying (printing of the second page).

In such a case, conventionally, first, printing is performed on a sheet P1 having a number smaller than the maximum number of sheets in one cycle (here, one sheet), and then, two sheets P2,
3 and the last two sheets of paper P4
5 was performed.

[0010]

By the way, in the circulating paper transport mechanism, the time required from the first sheet copy to the second sheet copy of the leading sheet of one circulation, that is, one circulation time is related to the number of sheets circulated. Constant. In other words, the time when the first sheet can be copied on the second side is the same whether the number of circulating sheets is smaller than the maximum number or the case where the maximum number of sheets are circulated.

For this reason, conventionally, the number of paper circulations (the number of repetitions of the first and second side copying) is increased by setting the number of paper circulations for the first time to be smaller than the maximum number. The time required for the entire double-sided copying from the start to the end of the discharge of all the sheets is lengthened, and there has been a problem that the productivity of the copy is reduced.

The present invention has been made in view of this problem, and has as its object to reduce the time required for duplex copying using a plurality of sheets.

[0013]

A copying machine according to the present invention comprises:
In order to solve the above-mentioned problem, multiple pages
Image reading means for automatically reading the original image sequentially and quantizing the original image, image storing means for storing the quantized original image, and printing on paper based on the image data read from the image storing means. An image forming means for forming a copy image, and a transport path length capable of accommodating n (n ≧ 2) sheets, inverting the sheet on which the copy image is formed on one side and re-feeding the sheet to the copy position and circulation of the sheet conveyance mechanism, the n
When performing double-sided copying using more than the same number of sheets of paper , start reading the first page of the original
Tie until the first sheet is fed by the paper transport mechanism
And the first paper circulation by the paper transport mechanism becomes n, so that the paper is continuously
So as to be continued paper feeding, and is controlled so as to (2n-1) after the time that page of replication initiation is possible of the original n th sheet reaches the copying position, the feed control Means.

[0014]

In double-sided copying using n or more sheets, first, n sheets from the first sheet to the n-th sheet are continuously fed to the copy position, and copied to the first side. Thereafter, in order to perform copying on the second surface, the sheet is reversed by the sheet transport mechanism and fed again to the copy position. At this time,
The timing for feeding the first sheet is as shown in FIG.
(2n-1) The timing is intentionally delayed by t1 so that the nth sheet reaches the copy position after the copy of the original image of the page becomes possible.

[0015]

FIG. 1 is a sectional front view showing the entire structure of a copying machine 1 according to the present invention. Copier 1 is an image reader IR
And a page copier PRT.

The main body of the image reader IR includes a scanning system 10 for reading a document placed on a document table glass 18 by decomposing the document into pixels, quantization of photoelectric conversion signals output by the scanning system 10 and various image forming modes. And a memory unit 30 that stores image data corresponding to the document. An automatic double-sided document feeder (ADFR) 500, which is an additional device also serving as a document cover, is attached to the upper portion of the main body so as to be openable and closable with its rear end as a fulcrum.

The scanning system 10 is an image reading mechanism of a line scanning system, and comprises an scanner 19 having a document irradiating lamp 11 and a mirror 12, fixed mirrors 13a and 13b, a condenser lens 14, and a CCD array. Sensor 1
6 and a scan motor M2 for driving the scanner 19. The image signal processing section 20 and the memory unit section 30 will be described later.

The ADFR 500 conveys the original set on the original stacker 510 onto the original table glass 18 by a feed roller 501, a separating roller 502, a separating pad 503, an intermediate roller 504, a registration roller 505, and a transfer belt 506. The read original is discharged by a discharge roller 50.
9, the document is discharged onto the document discharge tray 511. ADF
A document scale 512, a document sensor SE50 for detecting the presence or absence of a document, a document size sensor SE51,
And a discharge sensor SE52.

For example, when copying a plurality of originals, the operator sets the originals with the front surfaces thereof facing upward. Each original on the original stacker 510 is pulled out one by one from the lowermost original, and is accurately set at a reading position on the original platen glass 18 with its front surface facing downward. Then, in the case of the single-sided original mode, after the reading is completed, the original is conveyed to the left in the drawing and discharged so that the upper surface thereof becomes the front surface. In the case of the double-sided original mode, the original sent to the left after the reading of the front side is turned over by the reversing roller 507 and returned to the reading position on the platen glass 18, and after the reading of the back side is completed. It is sent to the left again and ejected.

The page printer PRT includes a print processing section 40 for outputting an exposure control signal, a print head 60 using a semiconductor laser 62 as a light source, a developing / transfer system 70A comprising a photosensitive drum 71 and its peripheral devices, and a fixing roller pair 84. Fixing / discharging system 70B having a sheet replenishing unit 600 and a fixing / discharging system 70B having a discharging roller 85 and the like.
And the like, and prints a copied image by an electrophotographic process based on the image data transferred from the image reader IR. At the bottom of the page printer PRT,
Two paper cassettes 80 capable of storing several hundred sheets of paper
a, 80b, paper size sensors SE11, SE12, and a paper feed roller group.

The laser beam emitted from the semiconductor laser 62 is deflected by the polygon mirror 65 in the main scanning direction.
The light is guided to the exposure position of the photosensitive drum 71 via the main lens 69 and various mirrors 67a, 68, 67c. The surface of the photosensitive drum 71 is uniformly charged by the charger 72. The latent image formed by the exposure becomes a toner image via a developing device 73, and the toner image is transferred onto a sheet by a transfer charger 74 at a transfer position (copying position).
Then, the sheet is separated from the photosensitive drum 71 by the separation charger 75, sent to the fixing roller pair 84 by the conveyor belt 83, and discharged face-up.

The re-feed unit 600 is mounted on the side of the page printer PRT as an additional device for automating double-sided copying. The re-feed unit 600 temporarily stores sheets discharged from the page printer main body by the discharge rollers 85, and switches back. It has the function of transporting and sending it back to the page printer body.

In the one-sided copy mode, the sheet is discharged onto the sheet discharge tray 621 through the sheet re-feeding unit 600. On the other hand, in the duplex copy mode,
The left end of the switching claw 601 is moved upward by a solenoid (not shown), and the paper discharged from the discharge roller 85 reaches the forward / reverse roller 603 through the transport roller 602. When the trailing edge of the sheet reaches the sheet sensor SE61, the forward / reverse roller 603 is inverted. As a result, the sheet is returned to the page printer main body. The returned sheet passes through the horizontal transport rollers 86a, 86b, and 86c in order, is sent to the timing roller 82, and waits. Here, when a plurality of sheets are continuously fed, the sheets are conveyed one after another at predetermined intervals so that the sheets do not overlap each other, and sent to the re-feeding unit 600. Since the transport path length of the paper is constant, the number of papers in one circulation (the maximum number of circulations) N by the re-feed unit 600 and the horizontal transport rollers 86a to 86c
Depends on the paper size.

FIG. 2 is a plan view of the operation panel OP, and FIG. 3 is a view showing an example of the operation screen. On the operation panel OP, a liquid crystal touch panel 91 for status display and various mode designations, a numeric keypad 92 for inputting numerical conditions for copying (number of sheets, magnification, etc.), and a clear key 93 for returning numerical conditions to standard values A panel reset key 94 for initializing the copy mode, a stop key 95 for instructing to stop copying, a start key 96 for instructing to start copying, and for specifying whether the original is a single-sided or double-sided original. A document designation key 100, a copy mode key 101 for switching between double-sided copy and single-sided copy, a finishing mode key 102 for designating the necessity of electronic sorting, and an input mode key 103 for designating the number of documents are arranged. Have been. In the electronic sort, the same original is M (M ≧ 2)
In the case of multi-copy printing one sheet at a time and a plurality of originals (for example, for three pages), the operation of printing the originals of each page one sheet at a time is repeated M times to produce a copy of M parts. . In non-electronic sort mode,
Each original is printed M sheets in the reading order.

When, for example, the initial screen Q10 is displayed on the liquid crystal touch panel 91, if the operator presses (turns on) the input mode key 103, the input mode becomes the document number input mode, as shown in FIG. A message screen Q prompting the user to specify the number of originals in place of the initial screen Q10.
11 is displayed. In this state, the number of documents can be specified by turning on the ten key 92 and the button Z11 in the screen. When the operator performs a designation operation, a designation completion screen Q12 is displayed instead of the message screen Q11 as shown in FIG.

FIGS. 4 and 5 are block diagrams showing the configuration of the control unit 100 of the copying machine 1. The control unit 100 is mainly composed of eight CPUs 101 to 108,
The U 101 to 108 are provided with ROMs 111 to 118 storing programs, respectively, and RAMs 121 to 128 serving as work areas for program execution.
The CPU 106 is provided in the memory unit 30.

The CPU 101 controls signal input and display from various operation keys on the operation panel OP. CPU10
2 controls each unit of the image signal processing unit 20 and
U103 controls the driving of the scanning system 10. CPU10
Reference numeral 4 controls the entire page printer PRT including the print processing unit 40.

The CPU 105 is responsible for the overall timing adjustment of the control unit 100 and the processing for setting the operation mode. Therefore, the CPU 105 performs serial communication with another CPU to transmit and receive commands and reports required for control.

The CPU 106 controls storage and reading of image information. The CPU 107 controls document conveyance by the ADFR 500. Then, the CPU 108 controls the re-feed unit 600.

FIG. 6 is a block diagram showing the configuration of the image signal processing section 20. The image signal processing unit 20 includes an A / D conversion unit 21, an image processing unit 22, an image monitoring memory 23, and a timing control unit 24 that outputs a synchronization signal of the operation of each of these units.

The A / D converter 21 is provided for the image sensor 16.
Are converted to 8-bit (256 gradation) image data. The image processing unit 22 performs image processing such as shading correction, MTF correction, gamma correction, and scaling processing, and outputs the processed image data D2 as read information. The image monitor memory 23 is used for storing sample data for shading correction.

FIG. 7 is a block diagram showing the structure of the memory unit 30. The memory unit 30 includes a bus switching unit 301, a binarization processing unit 302, a multi-port image memory 304, a code processing unit 305 having a compressor 311 and a decompressor 312, a multi-port code memory 306,
The image processing apparatus includes a rotation processing unit 308, a multi-value processing unit 309, and the above-described CPU 106 that controls these units, and is configured to compress and store image information in order to reduce the memory capacity. The image memory 304 has a capacity capable of storing image data of two pages read at a resolution of 400 dpi.

In the copy in the memory mode in which the image read by the original scanning (scan) is temporarily stored, the binarization processing unit 302 of the memory unit 30 receives the image data from the image signal processing unit 20 via the bus switching unit 301. Bit image data D2 is input. Binarization processing unit 302
Is multi-valued image data D by, for example, a dither method.
2 is converted into binary image data within a range in which restoration is possible. The image data after binarization is stored in an image memory 304.
Is written once.

The code processing unit 305 reads and compresses the image data written in the image memory 304 to generate code data (compressed data),
Write to. Further, the code processing unit 305 reads out the code data to be printed from the code memory 306, decompresses the code data, and writes the obtained image data to the image memory 304. Note that the compressor 311 and the decompressor 312 are configured to operate independently and in parallel with each other for the purpose of improving the copy speed. Is used to perform DMA transfer.

When one page of image data is reproduced by decompression, the data is read out from the image memory 304, subjected to a rotation process if necessary, and then multi-valued by the multi-value processing section 309. The image data is restored. The multi-valued image data is used as exposure control data by the print processing unit 4.
0 is transferred.

When such a document image is temporarily stored, the code memory 306 is managed by a management table MT1 provided in the RAM 126. FIG. 8 is a diagram showing the relationship between the management table MT1 and the code memory 306.

The code memory 306 is divided into memory areas in units of 32 Kbytes, and is used for writing (at the time of reading).
In order to allow simultaneous control of reading and printing (at the time of printing), code data for each page is stored in each area.

The management table MT1 includes a code memory 30
Number indicating area 6, page number of image data (number of document image) added in writing order (scanning order of document)
Various types of additional information such as a PN, a number of a connected area, and a compression method and a data length, which are necessary for compression / decompression processing, are stored.
06 is dynamically managed.

The "previous concatenation" in FIG. 8A indicates the concatenation in the forward direction of the area of every 32 Kbytes in each page. If this is "00", it is 1
Indicates that this is the first storage area for page data,
If it is other than "00", it indicates the number of the area connected before it. Similarly, "post-connection" indicates the last area when it is "FF", and indicates the number of the area connected later when it is other than "FF".

The CPU 106 reads out the image data from the image memory 304 and compresses the image data.
While creating the information of No. 1, the compressor 311 is controlled and stored in the code memory 306. When outputting image data, code data is read from the code memory 306 by the reverse operation. The information in the management table MT1 is deleted when the information of the corresponding page is normally read and the copy of the number (number of copies) M specified by the operator is completed.

Next, regarding the operation sequence of the copying machine 1 in the memory mode, a request command (Q), a report (A),
Or, the flow of data will be mainly described.

FIG. 9 is a diagram showing a schematic sequence of a memory mode write operation. In the memory mode writing operation, image data is transferred from the image signal processing unit 20 to the image memory 304.

First, C which manages the entire sequence
The PU 105 requests the CPU 106 for memory preparation. In response to this, the CPU 106 sets the bus connection state for transferring the image data D2 from the image signal processing unit 20 to the image memory 304 to the internal hardware, and sets a mode for binarization processing (for example, an error). Dispersion method,
Setting of a threshold value for background erasure, a binarization threshold value, etc.)
Make settings such as length information.

When these settings are completed and the preparation is completed, the CPU 106 notifies the CPU 105 of the completion of the memory preparation. CPU 105 is CPU 106, 102
When CPU 102 requests reading, CPU 102
03 is requested to scan.

A scan is started by the CPU 103,
When the scanner 19 reaches the image area of the document, the CPU 10
The read data (image data D2) is transferred from the image signal processing section 20 to the memory unit section 30 in accordance with the image processing mode set in Step 2.

When the scan is completed, the CPUs 102 and 106
When the CPU 105 notifies the completion of reading from the
Request data compression to U106. In response to this, the CPU 106 reads the address from the image memory 304, the XY length information, the write address to the code memory 306, and the mode (for example, M
H method), etc., and start each unit. As a result, the compression process is performed, and the code data is stored in the code memory 306.

When the compression process is completed, the CPU 106 notifies the CPU 105 of the completion of the compression. At this time, if the code memory 306 is full, a compression completion report added with a parameter indicating that compression is impossible is sent to the CPU.
Sent to 105. Thus, the CPU 105 can know that the code memory 306 has reached the memory full state.

FIG. 10 is a diagram showing a schematic sequence of the memory mode read operation. In the memory mode reading operation, image data is read from the image memory 304, and a copy image is printed on a sheet based on the image data.

The CPU 105 requests the CPU 106 to expand the data. The CPU 106 reads the address from the code memory 306, the data amount, the write address to the image data 304, the XY length information,
Twelve modes (for example, MH system) are set, and each unit is started. Thus, the decompression process is performed, and the image data is written to the image memory 304.

When the decompression process is completed, the CPU 105
The PU 106 is requested to prepare a memory for reading image data from the image memory 304. In response,
The CPU 106 sets the bus connection state for outputting the image data D3 from the image memory 304 to the print processing unit 40, the setting for the rotation processing, the start address of the read area of the image memory 304, and XY for the internal hardware.
Make settings such as length information.

When these settings are completed and the preparation is completed, and the notification is received, the CPU 105
04 is requested to print. CPU 104 to C
A paper feed report notifying the paper transport state is sent to the PU 105. Thereafter, the image data D3 read from the image memory 304 is output to the print processing unit 40, and printing is performed.

When printing is completed, the CPU 106, C
The PU 104 sends a print completion report and an ejection completion report to the CPU 105. The CPU 105 that has received these reports, if necessary,
06, a memory clear request is given.

Hereinafter, the operation of the copying machine 1 will be described in more detail with reference to flowcharts, focusing on control in double-sided copying (double-sided copy mode), which is a feature of the present invention.
FIG. 11 is a main flowchart of the CPU 101 for controlling the operation panel OP.

When the power is turned on, the CPU 101 first performs initialization to initialize the RAM 121, registers, and the like (# 11). Thereafter, setting of an internal timer that defines the length of one routine (# 12), key input processing (# 13) for accepting key operation, panel display processing (# 14) for performing display according to the operation, and other processing ( # 15) and waiting for the internal timer (# 16) are repeatedly executed. In addition, communication with another CPU is performed as an interrupt process at an appropriate time.

FIGS. 12 and 13 are flowcharts of the key input process. The CPU 101 has an original designating key 100
In response to turning on (see FIG. 2), if the original mode at that time is the one-sided original mode, the mode is switched to the two-sided original mode. Conversely, if the original mode is the two-sided original mode, the mode is switched to the one-sided original mode. Then, the mode after the switching is changed to CPU1.
05 (# 301 to # 305).

Similarly, when the copy mode key 101 is turned on, the copy mode is switched to the one-sided copy mode or the two-sided copy mode, and when the finishing mode key 102 is turned on, the finishing mode is changed to the electronic sort mode or the non-electronic mode. The mode is switched to the sort mode, and the fact is notified to the CPU 105 (# 306 to # 315).

In response to the input mode switching key 103 being turned on, if the input mode at that time is the document number input mode, the input mode is canceled. If the input mode is other than the document number input mode, the input mode is changed to the document number input mode. The mode is switched to (# 316-319).

When the set button Z11 is turned on in the document number input mode, the CPU 105 notifies the CPU 105 of the document number specified by the ten keys 92 (# 320-3).
22). Thereafter, when the start key 96 is turned on, the fact is notified to the CPU 105 (# 323, 324).

FIG. 14 is a main flowchart of the CPU 104 for controlling the page printer PRT. CPU
104 performs an initial setting (# 41), sets an internal timer (# 42), and controls a development / transfer system (# 4).
3), transport system control (# 44), fixing system control (# 4)
5), control of print processing section (# 46), other processing (#
47) and waiting for the internal timer (# 48) are repeatedly executed.

FIG. 15 is a flowchart of control of the transport system in FIG. First, the CPU 104 checks whether or not there is a print request from the CPU 105 (# 401).
If there is a print request, if the request is for printing on the front side (first side) of the sheet, the sheet is pulled out from the designated sheet cassette 80a or 80c and the transfer position (copy position) The paper supply process for supplying the paper is performed (# 402, 403). If the print request is to request printing on the back side (second side) of the sheet, a re-feeding process (# 404) of circulating the sheet by the re-feeding unit 600 or the like is performed. Then, other transport control processing (# 405) is executed, and the process returns to the main routine.

FIG. 16 shows a CPU for controlling the control of the copying machine 1.
FIG. 17 is a main flowchart of the CPU 106 for controlling the memory unit 30.

After performing the initial setting (# 51), the CPU 105 sets the internal timer (# 52),
Input data analysis processing (# 53) for checking input data from the server, mode setting processing (# 54) for determining an operation mode according to the operation content, command setting processing (# 55) for setting a command corresponding to the mode, a command Data set (# 56) that causes the communication port to wait on the communication port, other processing (# 57), and waiting for the internal timer (# 5)
Repeat step 8).

After performing the initial setting (# 61), the CPU 106 executes a command receiving process (# 62), a status transmitting process (# 63), an image memory writing process (# 64), a compression control process (# 65), Decompression control processing (# 66), image memory read processing (# 67), and other processing (# 6)
Repeat step 8).

FIG. 18 is a flowchart of the command setting process of FIG. When the mode is not the double-sided copy mode (that is, in the case of the single-sided copy mode), a command for a direct connection mode operation for transferring image data from the image signal processing unit 20 to the print processing unit 40 without passing through the memory unit 30 is transmitted. It is set (# 551, 557).

On the other hand, in the case of the double-sided copy mode, the CPU 10 indicating the detection result of the document sensor SE50.
The presence or absence of the document to be read is checked based on the report from # 7 (# 552). If there is a document, the above-described processing for the memory mode writing operation is performed, and subsequently, the input / output status of image data from the memory unit 30 to the print processing unit 40 is checked (# 553, 55).
4).

The check here specifically compares the variable (PR × m) with the variable PW. The variable PW indicates the number of pages of image data (the number of original images) stored in the memory unit 30, and the variable PR indicates the number of pages of image data read from the memory unit 30. The variable m is the number of composite images of so-called m-in-1 copy, and indicates the number of document images to be composited as an image for one page of a sheet. When m is "1", it is a normal copy, and an original image for one page (for example, an image of one single-sided original) is copied on one side of a sheet at a predetermined magnification. When m is “2”, two pages of original images (images of two single-sided originals or one double-sided original) are collectively copied so as not to overlap one side of one sheet of paper, and m is set to “4”. ", Document images of four pages are collectively copied on one side of one sheet. That is, the variable m indicates the number of document images to be printed on one side of one sheet, and the variable (PR ×
m) indicates the total number of document images read from the code memory 306 as print targets.

When the variable (PR × m) does not exceed the variable PW, that is, when image data to be read remains in the code memory 306, the CPU 105 sets the above-described memory mode read operation (# 555). When the variable (PR × m) exceeds the variable PW, the CPU
The write state and the read state indicating the progress stage of the memory mode operation are returned to “0” for # 106 (# 55).
6).

FIG. 19 is a flowchart of the memory write operation of FIG. In this routine, the write state is checked first (# 5500), and the following processing is executed according to each state (“0” to “3”).

In the state "0", it is checked whether or not there is a start request in response to turning on of the start key 96 (# 5501). If there is a start request, the variable PW
(The number of pages to which image data is written) is set to an initial value “1”, and
After the timer count value indicating the scan time per page is initialized, the state is advanced to "1"(# 55).
02-5504).

In state "1", a read command is registered in the command buffer (# 5511).
A command dedicated buffer (Q buffer) is prepared for each command in advance, and each command is transferred from the Q buffer to the communication port in the output data set (step # 56 in FIG. 16).

Then, a timing request instructing the CPU 103 to measure the scan time per page is set, and the state is advanced to “2” (# 5512, 551).
3). The scan time is used for setting the timing of sheet conveyance as described later.

In state "2", the CPU 106
When a read completion report (read completion A) is received from the CPU 102, the value of the variable PW is registered in the compression Q buffer, and the state is advanced to “3” (# 5521 to 552).
3).

In state "3", the CPU 106
When the compression completion report (compression completion A) is received from, the scan time measurement request is reset (# 5531, 5).
532). Then, the variable PW is incremented by one and the state is returned to “1” (# 5533, 5534). As a result, while the original remains in the original stacker 510, a series of operations of compressing the read original image and writing the compressed original image into the code memory 306 are repeatedly performed.

FIG. 20 is a flowchart of the memory read operation of FIG. Also in this routine, the read state is checked first (# 5600), and the following processing is executed according to each state ("0" to "3").

In the state “0”, a variable PR (the number of readout pages of image data) is set to an initial value “1” and a variable PR indicating the number of times image data of the same page should be read out.
The number of copies (number of copies) M specified by the operator is set in (M) (# 5601 and 5602). Variable PR
(M) is decremented by one each time image data of the same page is read, and when this value becomes "0", it means that the necessary number of copies of the corresponding page have been completed.

Further, a variable j indicating the number of sheets existing in the circulation path (re-feeding standby number) is set to an initial value “0” (# 5603), and thereafter the state is advanced to “1” (# 5604). . The circulation path is a sheet conveyance path from the transfer position to the timing roller 82 through the sheet re-feed unit 600.

In state "1", a re-print is performed to determine whether the next print to be performed is the first-side print on the first sheet (that is, the first print of double-sided copy). It is checked whether or not the number of waiting sheets for feeding j is “0” (# 5611).

If the re-feed standby number j is “0”,
A paper feed weight determination process, which is a process unique to the present invention, is performed, and it is checked whether or not the result is “paper feed weight present” (# 5612, 5613). In other words, intentionally delaying the feeding timing of the first sheet (feeding weight) in order to maximize the number of paper circulations in each time is effective in shortening the time required for duplex copying. Check whether or not.

In the case of "paper feed wait", the process returns to the main routine without updating the state. If the sheet has already been fed (if j is not "0") and the result of the feed weight determination is "no feed weight", the state is advanced to "2"(# 5614).

In state “2”, the page number to be printed (the page number of the data to be read from code memory 306) CPN is registered in the decompressed Q buffer (#
5621). At this time, for example, in the case of the 2-in-1 mode, image data for two pages is to be printed.

Then, the next print is made on the surface of the paper (first
In the case of printing on the (front side), the “front side” is registered in the print Q buffer, the re-feeding standby sheet number j is incremented, and then the state is advanced to “3” (# 5622 to 562).
4, 5627). If the next print is a print on the back side (second side) of the sheet, the state is updated after registering the "back side" in the print Q buffer and decrementing the re-feed standby number j (# 5625). ~ 562
7). Paper feeding or re-feeding is performed as described above according to the registered contents of the print Q buffer (see FIG. 15).

In state "3", the CPU 104
When the print completion report (print completion A) is received from the printer, if the printing of the front side (first side) is completed and the paper feed restriction timer is not set, the paper feed restriction timer is set, and the read page switching process is performed. Is performed, the state is returned to “1” (# 5631 to 5636).
When the printing of the back side (second side) is completed, the read page switching process is executed to update the state.

The feed restriction timer is a timer for providing an appropriate interval (sheet passing interval) between the sheets so that the sheets do not overlap each other when a plurality of sheets are conveyed continuously. .

FIGS. 21 and 22 are flow charts for determining the paper feed weight in FIG. First, it is checked whether or not scanning of all documents (strictly speaking, storage of document images) has been completed (# 6001). When the scanning is completed, the image data can be read out from the code memory 306 and printed in an arbitrary order. In this case, "no paper feed wait" is set, and the flow returns to the memory read operation flow of FIG. 20 (# 6016).

If the scanning has not been completed, it is necessary to determine the necessity of the paper feed weight according to various conditions. First, it is checked whether or not it is the first paper circulation, that is, whether or not the next print is the first print (print on the front surface of the first paper) in duplex copying (# 6002). .

If it is the first paper circulation, it is checked whether or not the original is a one-sided original (operation state of the original designating key 100) (# 6003). In other words, in the case of a two-sided original, the original is flipped between the front side scanning and the back side scanning, so the scanning time per page is longer than that of the one-sided original, and the number of circulations is reduced. Therefore, if the scanning of a predetermined page is completed, the time required for duplex copying increases. For this reason, the first paper circulation feeding weight is performed only for a one-sided original.

Next, the number of copies M is checked (# 6).
004). If it is not a single copy in which one document image is printed only once (if it is a multi-copy), it is checked whether or not it is in an electronic sort mode in which sheets are discharged in a form of being sorted for each set (# 6005). In the case of multi-copy in the non-electronic sort mode, since the same original image is continuously printed for M sheets, the scanning of the next original image is completed during the printing of one original image. Is unnecessary.

In the case of single copy and multi-copy in the electronic sort mode, that is, in the case where a plurality of document images read in order are divided into odd pages and even pages and printed alternately by the number of circulating sheets, the following processing is executed. .

Based on the length of the sheet of the designated size in the sub-scanning direction and the pre-supplied re-feeding conditions (circulation path length L, sheet interval d), the sheet that can be accommodated in the circulation path The number (the most frequently circulated number) N is calculated (# 60).
06). Also, the number of sheets (circulation number) n to be actually circulated is calculated in consideration of the number of original pages and the number m of composite images of m-in-1 copy (# 6007).

Subsequently, the number of compression completed tasks is calculated based on the state of the code memory 306 (# 6008), and it is checked whether the number of compression completed tasks is smaller than twice (2n) the number of circulations n (2n) (# 6008). # 6009). Here, the task means a document image to be printed on one side of a sheet. For example, in a 2-in-1 copy, a document image for two pages is one task. Further, the compression completion task is performed by the code memory 306.
Task written in

The number of tasks whose compression has been completed is twice (2
If it is larger than n), the document image to be printed has already been stored in the code memory 306, and printing is possible for the number of circulating sheets.

When the number of compression completed tasks is smaller than 2n, taking into account that m-in-1 copy requires m times as long as the normal time, the compression wait time (time required for compressing the original image to be printed) Paper feed standby time) t1
Is calculated (# 6010), and the compression wait time t1 is compared with the required circulation time (# 6011).

If the compression wait time t1 is shorter than the required circulation time, the compression of the image data to be printed on the back side during the circulation of the paper is completed. That is, even if the sheet is fed without delaying the sheet feeding, the image data is ready to be read at the time of printing on the back side, so that the data from the image reader IR is not in time and printing is not hindered.

However, if the image data on the back side of the sheet is not enough in refeeding the sheet, copying cannot be performed. In the circulation-type sheet conveyance, the sheet once fed is conveyed without stopping on the way, so if the preparation for outputting the image data cannot be made in time for the printing, the sheet feeding must be postponed. However, if the number n of circulations is smaller than the maximum number N of circulations, the number of circulations increases, and productivity decreases. For example, the circulation path length (paper moving distance-
If the paper length is 1449 mm, the paper passing interval is 84 mm, and the transport speed is 165 mm / s, the copy time increases by about 8.3 s for each increase in the number of circulations.

Therefore, in the copying machine 1, the start timing of the continuous paper feed to be circulated is delayed within a range in which the time required for copying from the time when the start key 96 is turned on until the last paper is discharged is minimized. Thus, the number of circulations is reduced by circulating the sheets having the maximum circulation number N. That is, in step # 6010, the paper feed standby time t1 is set so that the number of circulating sheets is maximized and the number of circulation times is minimized, as described later.
If 1 is longer than the required circulation time, the entire required time will be rather long due to the delay in sheet feeding. In such a case, a timer for minimizing the total required time is set in step # 6014. .

In step # 6011, the compression wait time t
If 1 is longer than the required circulation time, it is determined whether or not the count of the paper feed weight control timer has ended (# 60).
12). The time counted by the paper feed weight control timer is the above-described required circulation time.

If the paper feed wait control timer is not in the end state and is not counting, the CPU 104 sets a paper feed wait timer timing request to the CPU 104 (# 601).
3-6014). Then, “feeding weight present” is set, and the flow returns to the memory reading operation flow of FIG. 20 (# 6015).

FIG. 23 is a flowchart of the process of setting the number of circulations in FIG. First, it is checked whether or not the number of documents has been determined (# 6701). The number of documents is input by the ten keys 92. Also, a document sensor SE50
The number of originals is determined when is turned off from the on state.

If the number of original pages has not been determined, the most circulating number N is set as the next circulating number n (# 6).
708). If the number of manuscript pages is fixed,
The circulation number n is set in consideration of the m-in-1 copy as follows.

In the case of a double-sided original, a value twice as many as the number of originals is set as the number of original pages (the number of original images). In the case of a single-sided original, the value of the number of originals is set as the number of original pages (# 6703). , 6704).

Next, [(number of original pages / m) -PR × m] is set as the remaining number of prints (# 670).
5). Here, m is the number of original images to be printed on one side of the sheet as described above.

If the remaining number of prints is smaller than twice the maximum number N of circulations, (the number of remaining prints / 2) is set as the number of circulations n (# 6707). As a result, the compression wait time is shortened, and the timing of sheet feeding can be advanced.

FIG. 24 is a flowchart of the compression wait time calculation process of FIG. 1 for m-in-1 copy
Since m scans are required to obtain the image data of a task, the compression weight time per task is [m
× scan time per original] (# 610)
1).

As the number of tasks waiting for compression, (circulation number n × 2—the number of tasks completed for compression−1) is set, and as the compression wait time t1, (compression wait time per task × the number of tasks waiting for compression) is obtained. Set (# 6102,
6103).

FIG. 25 is a flowchart of the read page switching process of FIG. The above variable PR (M) indicating the remaining number of times of multi-copy is decremented, and it is checked whether the print completed immediately before is a print on the front side of a sheet (# 7001, 7002).

In the case of printing on the front side (first side),
During the counting of the sheet feed restriction timer, the number of sheets for re-feed standby j and the maximum number of sheets N for circulation are compared (# 7003, 7004). When the re-feeding standby number j is smaller than the maximum circulation number N and the feeding of a new sheet is permitted, the variable PR (M) is continuously set.
It is checked whether or not is “0” (# 7005).
That is, it is checked whether or not the printing of the original image of the same page has been completed the number of times corresponding to the designated number of copies M.

If the variable PR (M) is "0", "2" is added to the page number CPN to be printed in order to print the next image on the front side of the paper (# 7006). If the variable PR (M) is not “0”, the current print target page number CPN is held to continuously print the same image.

Then, when shifting from the front side to the back side, in order to search for the page on the back side, the value of the page number CPN to be printed is registered in the built-in page buffer of the ring buffer format (# 7007), and the registration pointer is updated. (#
7008). The built-in page buffer and the registration pointer will be described later in detail.

In step # 7004, if the re-feed standby sheet number j is equal to the maximum circulation number N, the smallest page number of the front-printed page is read from the internal page buffer (# 7009, 7010). The read pointer is updated (# 7011), and the value obtained by adding "1" to the page number read in step # 7010 is set as the print target page number CPN (# 7012).

If the feed restriction timer has expired in step # 7003, the flow advances to step # 7010. As a result, the code data stored in the code memory 306 is read out and printed as soon as possible, and the process shifts to reading of the next document.

On the other hand, if the printing is to be performed on the back side in step # 7002, it is determined whether or not the re-feeding standby sheet number j is not “0”, that is, whether or not the paper for the back side printing remains in the circulation path. Is checked (# 7009).

If the sheet still remains, the flow advances to step # 7010. On the other hand, if no paper remains, it is checked whether the variable PR (M) is “0” (# 7013). If the variable PR (M) is not “0”,
Since it is necessary to print the front surface again, the print target page number CPN is decremented by one (# 701).
4) Then, the process proceeds to step # 7007, where the decremented print target page number CPN is registered in the internal page buffer.

If the variable PR (M) is "0", since the printing of the same image has been completed for M sheets, the page number CPN to be printed is incremented so as to proceed to the printing of the next image (# 7015). Then, a memory clear request for instructing the CPU 106 to delete unnecessary image data is set (# 7016). Then, step # 700
In step 7, the incremented print target page number CPN is registered in the internal page buffer.

FIG. 26 shows the structure of the built-in page buffer PBF. FIGS. 27 and 28 show the structure of the built-in page buffer PB.
It is a figure showing an example of a state transition of F. The operation of the internal page buffer PBF will be described with reference to these figures.

In step # 7007, only the odd-numbered page number CPN to be printed is registered in the internal page buffer PBF. Each pointer is sequentially updated clockwise.

The operation of the built-in page buffer PBF will be described with a specific example. Here, four single-sided originals (1 to 4
Page), the memory (code memory 306) has a capacity of 5 pages, the number of copies N is 6, and the maximum number of circulations N is 10.

Reading of an original, that is, writing to the memory, is performed in the order of 1 (page), 2, 3, 4, and printing on paper is performed in the order of 1, 1, 1, 1, 1, 1, 3, 3 3,
3, 2, 2, 2, 2, 2, 2, 4, 4, 4, 4, 3,
The order is 3, 4, and 4. In this case, all four originals can be written in the memory.
Therefore, when the fourth page of the third page (front side) is printed, the re-feed standby number j becomes 10, and the circulation path becomes full. Therefore, at that time, two pages (back side) and four pages (back side) are printed, and thereafter,
Print the remaining two 3 and 4 pages.

First, in the internal page buffer PBF in the initial state shown in FIG. 27A, the value "1" of the print target page number CPN is registered at the position indicated by the registration pointer W [FIG. 27B]. The pointer W is updated [FIG. 27 (c)]. By repeating these operations, the page number CPN is written into the internal page buffer PBF.

Each time printing on the front side of one sheet of paper is completed, the smallest printed page number is read in step # 7010 [FIG.
(A)], the read pointer R is updated in step # 7011 [FIG. 28 (b)]. By this repetition, the page number of the image to be printed on the front surface is read from the built-in page buffer PBF. In step # 7012, 1 is added to the read page number, for example, 2 pages for 1 page, 4 pages for 3 pages, and the page number of the back side corresponding to the front side. Is required.

According to the above embodiment, the code memory 306
Unless the new image data can be stored and the paper circulation path is not full, scanning and printing of the original are performed continuously, respectively. The waiting time for reversing the paper and refeeding it is shorter than
Copy productivity can be greatly improved.

In the above embodiment, the code memory 306
As the timing for clearing the data, the pages in which the number of copies M has been printed may be sequentially cleared, and the image data of the next document may be written in the cleared page area. Although the image data obtained from the document is compressed and stored in the code memory 306 as code data, the image data may be stored as it is without compression.

In the above-described embodiment, if the number of originals has been input before the start of copying by an operator's designation operation or the like, the optimal copying process is determined at the time of inputting the number of originals. Since the number of sheets to be circulated each time can be set, the paper feed wait time t1 can be determined based on the time conditions under which each document can be copied.

In the above-described embodiment, the table for associating the paper size with the maximum circulating number N is previously stored in the memory without determining the maximum circulating number N by calculation.
The maximum circulation number N may be set by referring to the table according to the designation of the paper size.

The present invention can also be applied to composite copying in which a sheet is re-fed without being turned upside down and printing is performed a plurality of times on the same side.

[0125]

According to the present invention, the time required for double-sided copying using a plurality of sheets can be reduced, and the productivity of a copy can be increased.

[Brief description of the drawings]

FIG. 1 is a cross-sectional front view showing the entire configuration of a copying machine according to the present invention.

FIG. 2 is a plan view of an operation panel.

FIG. 3 is a diagram illustrating an example of an operation screen.

FIG. 4 is a block diagram illustrating a configuration of a control unit of the copying machine.

FIG. 5 is a block diagram illustrating a configuration of a control unit of the copying machine.

FIG. 6 is a block diagram illustrating a configuration of an image signal processing unit.

FIG. 7 is a block diagram illustrating a configuration of a memory unit.

FIG. 8 is a diagram showing a relationship between a management table and a code memory.

FIG. 9 is a diagram showing a schematic sequence of a memory mode write operation.

FIG. 10 is a diagram showing a schematic sequence of a memory mode read operation.

FIG. 11 is a main flowchart of a CPU that controls an operation panel.

FIG. 12 is a flowchart of a key input process.

FIG. 13 is a flowchart of a key input process.

FIG. 14 is a main flowchart of a CPU that controls a page printer.

FIG. 15 is a flowchart of control of the transport system in FIG. 14;

FIG. 16 is a main flowchart of a CPU that controls the control of the copying machine.

FIG. 17 is a main flowchart of a CPU that controls a memory unit.

18 is a flowchart of a command setting process of FIG.

FIG. 19 is a flowchart of a memory write operation of FIG. 18;

20 is a flowchart of a memory read operation of FIG.

FIG. 21 is a flowchart of the paper feed weight determination of FIG.

FIG. 22 is a flowchart of a paper feed weight determination in FIG. 20.

FIG. 23 is a flowchart for setting the actual circulation number in FIG. 21;

FIG. 24 is a flowchart of a compression weight time calculation process of FIG. 22;

FIG. 25 is a flowchart of a read page switching process of FIG. 20;

FIG. 26 is a diagram showing a configuration of a built-in page buffer.

FIG. 27 is a diagram illustrating an example of a state transition of a built-in page buffer.

FIG. 28 is a diagram illustrating an example of a state transition of a built-in page buffer.

FIG. 29 is a schematic diagram illustrating an example of double-sided copying.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Copier (digital copier) 30 Memory unit part (image storage means) 70C Paper transport system (paper transport mechanism) 105 CPU (paper feed control means) IR image reader (image reading means) PRT page printer (image forming means)

Claims (1)

(57) [Claims] 1. A method for automatically and sequentially printing a plurality of originals one page at a time.
Forming an image reading means for quantizing the original image is read, an image storage means for storing the original image quantized, a copy image on a sheet based on image data read out from said image memory means An image forming means, and a circulating sheet having a conveyance path length capable of accommodating n (n ≧ 2) sheets, reversing the sheet on which a copy image is formed on one side, and re-feeding the sheet to a copy position. At the time of double-sided copying in which copying is performed using a transport mechanism and a number of sheets equal to or greater than n, whether to start reading the first page of the document
To the first sheet feeding by the paper transport mechanism.
Delaying the timing at which the, number of the first sheet circulation by the paper transport mechanism becomes n Like
The paper is fed continuously, and (2n-
1) th page replication initiation can become after the time of the n-th sheet is controlled so as to reach the copy position, a digital copying machine, characterized in that and a paper feed control means.