JPH09107447A - Digital copying machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent picture compressing time from being prolonged vainly even in the case where a picture having been read is held after being compressed by providing a picture memory part to store picture data obtained by reading an original, and making the picture memory part capable of being used effectively by making it match with original size. SOLUTION: The digital copying machine provided with the picture memory part 30 to store the picture data obtained by reading the original by an image reader, is provided with a CPU 106, a ROM 116 and a RAM 126 which are means to set the area of an input picture memory 302 so as to match with the maximum original size capable of being read by the image reader, and an original size detecting part 301 which is the means to detect the original size from the picture data inputted successively to the area of the input picture memory 302, and starts original size detection processing after the start of the storage of the picture data or from the middle of the storage. The area of the input picture memory 302 set so as to match with the maximum original size is changed so as to match with the original size detected by the original size detecint part 301.

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 having an image memory section for storing image data obtained by reading an original with an image reader.

[0002]

2. Description of the Related Art In a conventional digital copying machine of this type,
After detecting the document size in advance, there is a method of determining the size of the input image memory area and reading the image data there, but without detecting the document size in advance, the image data is read into the memory and the image on the memory is read. There is also one that detects the document size from the.

[0003]

However, in the case of a digital copying machine which reads the image data into the memory and detects the original size from the image on the memory, the original size of the original is not known. It must be set according to the maximum document size that can be read by the reader.

As a result, even if the actual document size is small and the memory area for it is small, it is necessary to prepare the maximum memory area first and read the image into it, which is inefficient in memory usage. It was Also, when adopting a configuration in which the read image is compressed and held in the image holding memory, the image stored in the input image memory area set corresponding to the maximum document size does not need to correspond to the document. Therefore, there is a problem in that the entire image including the image area must be compressed, and therefore the compression time, and hence the decompression time after compression, is lengthened.

Therefore, the present invention is a digital copying machine provided with an image memory section for storing image data obtained by reading an original with an image reader, and the image memory section can be effectively used according to the original size. An object of the present invention is to provide a digital copying machine that does not prolong the image compression time, and thus the decompression time after compression, even when adopting a configuration for compressing and holding a read image.

[0006]

A digital copying machine of the present invention for solving the above-mentioned problems is a digital copying machine having an image memory unit for storing image data obtained by reading an original with an image reader, Means for setting the input image memory area for storing the received image data in the image memory section corresponding to the maximum document size readable by the image reader, and the image data stored in the input image memory area From the document size detection means for starting the image data storage or starting the document size detection process during the storage, and the input image memory area set corresponding to the maximum document size by the document size detection means. And a means for changing the size of the document to be detected.

As a more specific example of this copying machine, the image memory section is provided with an image holding memory area capable of holding a plurality of images, and image data is transferred from the input image memory area to the image holding memory area. Means for deleting the stored image area in the input image memory area unnecessary for the detected document size when the document size is detected by the document size detecting means, the necessary image area data is stored. A digital copying machine that switches to a mode of transferring from the input image memory area to the image holding memory area can be mentioned.

In any case, for example, the means for setting the input image memory area in the image memory unit sets the input image memory area in units of one or two or more bands, and the input image memory area is It is conceivable that the means for changing the size of the original detected by the original size detecting means may change the input image memory area for each band.

According to the digital copying machine of the present invention, initially, the input image memory area for storing image data is made to correspond to the maximum document size readable by the image reader by the input image memory area setting means. The image data obtained by reading the original with the image reader starts to be stored in the input image memory area. When the image data storage is started or during the image data storage (for example, when the input image memory area is set in band units, image data is stored in one or more predetermined band units). so)
The document size detection process by the document size detection means is started.

In the input image memory area set corresponding to the maximum original size, when the original size is detected by the original size detecting means, the input image memory area changing means detects the original size. The input image memory area is changed with respect to the original size, and the unnecessary memory area is released thereby, and the memory section is put into a state in which it can be effectively used for other purposes.

Further, when the image memory section is provided with an image holding memory area capable of holding a plurality of images and the image data transfer means is provided, when the document size is detected by the document size detecting means. The storage image area in the input image memory area unnecessary for the detected document size is deleted, and the necessary image area data is transferred from the input image memory area to the image holding memory area. Further, in the case of adopting a configuration in which an image is compressed and held by deleting unnecessary image areas in this way, the image compression time, and thus the decompression time after compression, cannot be lengthened.

The detection of the document size by the document size detecting means is, for example, in the case of an ordinary rectangular document, the size of the document in the lateral direction (in other words, the main scanning direction in the document scanning by the image reader), and The size of the document in the vertical direction (in other words, the sub-scanning direction in the document scanning by the image reader) may be considered. Then, it is conceivable that the horizontal size of these two original sizes is detected earlier. The change corresponding to the document size in the input image memory area is
This is performed in both the horizontal and vertical directions of the original.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. FIG. 1 is a sectional view showing the overall structure of a copying machine according to the present invention. This copying machine is a digital copying machine including an image reader IR and a page printer PRT.

The main body of the image reader IR is a scanning system 10 for reading an original document placed on the original table glass 18 by dividing it into pixels, quantization of photoelectric conversion signals output from the scanning system 10, and various image forming modes. An image signal processing unit 20 that performs signal processing according to the above, and a memory unit unit 30 that stores image data corresponding to a document. An automatic double-sided document feeder (ADFR) 500, which is an additional device that also serves as a document cover, is mounted on the upper part of the main body so that it can be opened and closed with its rear end as a fulcrum.

The scanning system 10 is an image reading mechanism of a line scanning system, and includes an original irradiation lamp 12 and a mirror 13a.
And a fixed mirror 13b and 13c supported by a frame 14, a condenser lens 15, an image sensor 17 including a CCD array, a reflection mirror 16 that guides light passing through the lens 15 to the sensor 17, and the scanner 11 It is composed of a scan motor M2 for driving the. The original image can be scanned by driving the scanner 11 in the direction of arrow α in FIG. 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 501 onto the original table glass 18 by the paper feed roller 502, the separation roller 503, the separation pad 504, the intermediate roller 510, the registration roller 505 and the conveyor belt 506. , The document after reading is ejected by roller 5
Then, the document is discharged onto the document discharge tray 508. For example, when copying a plurality of originals, the operator stacks the originals with the front side facing upward. Each original on the original stacker 501 is pulled out one by one from the lowermost original, and is accurately set at the reading position on the original table glass 18 with the front side facing down. Then, in the single-sided original mode, after the reading is completed, the original is conveyed in the left direction in the drawing and is ejected so that the upper surface becomes the front surface. In the case of the double-sided original mode, the original fed to the left after the front side is read is reversed by the reversing roller 507 and returned to the reading position on the platen glass 18, and after the rear side is read. It is sent to the left again and discharged.

The page printer PRT has a print processing unit 40 for outputting an exposure control signal, a print head 60 using a semiconductor laser 61 as a light source, a developing / transferring system 70A including a photosensitive drum 71 and its peripheral devices, and a fixing roller pair 86. And an image reader IR including a fixing / discharging system 70B having a sheet discharging roller 87 and a sheet conveying system 80.
The copied image is printed by the electrophotographic process based on the image data transferred from the device. Page printer PR
Below the T, there are two sheet cassettes 81a and 81b that can store several hundred sheets of paper, sheet feeding rollers 82a and 82b that pull out sheets from each set, a sheet feeding intermediate roller group, and a timing roller pair 83. It is provided.

The laser beam emitted from the semiconductor laser 61 is deflected in the main scanning direction by the polygon mirror 62,
Main lens 63 and various mirrors 64a, 64b, 64c
, And is guided to the exposure position of the photosensitive drum 71. The photosensitive drum 71 is rotationally driven in the direction of the arrow CCW in FIG. 1, and its surface is uniformly charged by the charging charger 72 prior to exposure. The latent image formed by exposure is the developing device 7
3 is developed into a toner image, and on the other hand, the sheet supplied from either cassette 81a or 81b is sent to the transfer position in synchronization with the toner image by the timing roller pair 83, and the toner image is transferred at the transfer position. Transcription charger 7
4 is transferred onto the sheet. Then, the sheet is separated from the photoconductor drum 71 by the separation charger 75, is sent to the fixing roller pair 86 by the conveyance belt 85, the toner image is fixed there, and the sheet discharge tray 87 is discharged by the sheet discharge roller pair 87.
8 is discharged. After the transfer, the toner remaining on the photosensitive drum 71 is removed and cleaned by the cleaner 76, and the residual charge is erased by the eraser 77.

FIG. 2 is a plan view of the copier operation panel OP. On the operation panel OP, a liquid crystal touch panel 91 for status display and various mode designations, a ten key 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 a copy mode, a stop key 95 for instructing copy stop, a start key 96 for instructing copy start, and a single-sided original or a double-sided original Original designation key 97,
Finishing mode key 9 for specifying the necessity of electronic sorting
8 and the input mode key 99 for specifying the number of originals
Is arranged. For electronic sorting, the same manuscript
≧ 2) It is a multi-copy that prints one by one, and
When there are a plurality of documents (for example, three pages), the operation of printing one document of each page is repeated M times,
This is a function of producing a duplicate of the M part. In the non-electronic sort mode, each original is printed M sheets in the reading order.

3 and 4 are block diagrams showing the configuration of the control unit 100 of the copying machine described above. Control unit 100
Is composed mainly of seven central processing units (hereinafter referred to as “CPU”) 101 to 107.
U101 to 107 are provided with ROMs 111 to 117 storing programs, and RAMs 121 to 127 serving as work areas for executing the programs. The CPU 106 is provided in the memory unit 30.

The CPU 101 controls signal input and display from various operation keys of the operation panel OP. CPU10
A CPU 2 controls each part of the image signal processing unit 20, and a CPU
Reference numeral 103 controls the driving of the scanning system 10. CPU 104
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 other CPUs to send and receive commands and reports necessary for control.

The CPU 106 controls storage and reading of image information. The CPU 107 controls the document transportation by the ADFR 500. FIG. 5 shows the memory unit section 30.
FIG. 3 is a block diagram showing the configuration of FIG. Memory unit 30
Is an input image memory 302 that stores the read image data D2 sent from the image signal processing unit 20, a compressor 304 for compressing and expanding an image, an expander 305, and a code memory 306 that holds the compressed image data. An output image memory 303 for holding image data to be sent to the print head 60, a document size detecting section 301 for detecting an effective document size area from the image data sent from the image reader IR, and a rotator for performing a rotation process when outputting image data. 307, a ROM 116 for holding a program for operating the memory unit section 30, a (system) RAM 126 for holding a state for operating the program, and a CPU 106.

The image data D2 read by scanning the original is input image memory 3 through the data bus.
It is put in 02. The document size detecting unit 301 detects the effective area from the image data stored in the input image memory 302. As shown in FIG. 6, the input image memory 3
The image input to 02 is divided into a region X read as a document image and a region Y where the document is not placed. The area Y shown in the figure is processed as described later.

The original size detecting section 301 scans the image data on the input image memory 302 to determine this area. In order to actually discriminate the area as the effective area, information on the horizontal length and the vertical length of the document is required. Therefore, in the illustrated example, the vertical boundary line A between the regions X and Y and the horizontal direction. A process of detecting the boundary line B is performed. As for the algorithm of this image size detecting method and the like, a conventionally known image processing technique is used, and therefore detailed description thereof is omitted.

It is possible to store a plurality of images in the code memory 306, and a code management table (see FIG. 7) for managing these images is created in the (system) RAM 126 to manage the images. The table has a portion for storing information (T-1) in image units and information (T-2) in block units. As will be described later, the read image is not compressed as it is for one page, but one page is divided into several blocks and compressed, and placed on the code memory.

The image unit information (T-1) portion stores page unit information such as whether the document size is fixed, some sizes, how many blocks have been compressed, and how far compression and decompression have progressed. To do. Block unit information (T
The -2) portion stores the above-mentioned block unit information. That is, the number of lines in the block, a pointer indicating where the compressed image is arranged in the code memory, the compressed image size, and the like are stored.

This table is created when compression starts on a page-by-page basis, and is erased when the required number of copies is printed out. Next, the memory unit section 3 during the copy operation
The operation of 0 will be described. The document is scanned by the image reader IR, and the read image is stored in the input image memory 302 as the image data D2 through the data bus. The image stored in the input image memory 302 is compressed by the compressor 304 and transferred to the code memory 306. Further, the compressed image in the code memory is expanded by the decompressor 3
At 05, the original image is restored and sent to the output image memory 303. When the image expansion is completed, the output image memory 303
Exposure control data D3 through the bus while synchronizing with
Is transferred to the print processing unit 40. At this time, the output image memory 303 is operated by operating the rotator 307.
It is possible to change the reading direction of the image, which enables image rotation (see FIG. 8).

By the way, as shown in FIG. 6, if an image consisting of regions X and Y is read into the input image memory 302, the region Y which is noise is wasted. As a problem caused by this, since the area Y is compressed, the compressor 3
Since more image data passes through 04, the compression time becomes longer. The decompressor 305 also prolongs the decompression time during decompression. There is a wasteful area in the memory, so the memory cannot be used for other purposes.

It can be seen from FIG. 6 that the boundary A can be detected at an early stage of reading when viewed from the image input direction. Therefore, in this copying machine, when the boundary of A is determined in the storage of the image data in the memory 302, the input image memory 30
We will deal with this by reducing the width of 2 to a fixed size. For example, as shown in FIG. 9, the input memory size is divided into horizontal bands in the vertical direction, and while the image is being input to the input image memory 302, the horizontal size of the divided bands is reduced (hereinafter, This division unit is called a "band").

Since the decompression side can decompress at that point if compressed in band units, the output image memory 303 is also controlled in the same manner as the input image memory 302 (see FIG. 10). At this time, the width of the output image memory can be reduced from the middle like the input image memory, and the above-mentioned problem can be dealt with, and the memory on the output side can also be reduced, so that the above-mentioned problem can also be dealt with.

Now, in order to solve the above-mentioned problems, the input image memory 302 and the output image memory 303 are the paper 1
It is possible to operate with a page of memory,
Here, a structure that can be operated as a band buffer is adopted. FIG. 11 shows this input image memory 30.
It is the figure which showed the 2nd band operation. First, an image is input to the band a1 (step S11). When the image is input and the band a1 is full, the input signal (image data D2 from the data bus) is switched to the band b1. At this time, since the band a1 becomes compressible, it is compressed using the compressor 304 and transferred to the code memory 306 (step S12). Further, when the band b1 is full, the input signal is switched to the band a1 side, and the band b1 side is image-compressed (step S13).
Then, the process is advanced by repeating this operation. Here, the operation speed of the compressor 304 is guaranteed to be faster than the speed at which the input signal (image data D2 sent through the data bus) by scanning the original is input.

FIG. 12 is a diagram showing a band operation of the output image memory 303. First, the band a2 is expanded (step S21). The image is expanded and band a
When 2 is full, output of the image data D3 to the bus is started. At this time, since the band b2 is empty, the image is expanded here (step S22). When the output of the band a2 is completed, there is an expanded image in the band b2, so the output is switched to the band b2 side and the expansion is performed to the band a2 side (step S23). Then, the process is advanced by repeating this operation. Here, the operation speed of the decompressor 305 is guaranteed to be faster than the output speed of the image data D3 to the data bus.

Since the decompression operation can be performed as long as there is a compressed image as described above, the band is explained as two bands in FIGS. 11 and 12, but as long as there is an empty area in the output image memory 303, a band is provided. It is possible to reduce the expansion process by securing and expanding. Further, as described above, the memory size in the horizontal direction is reduced midway, so that more memory can be used.

However, there are cases where the output image memory 303 side cannot perform band operation. As described above, when the rotator 307 operates to output in a direction other than 0 °, the band operation cannot be performed because the output image memory 303 may be read in the vertical direction. Therefore, an area for one page is secured on the image memory 303 to operate. Also in this case, the area is secured as much as possible on the memory, and the memory is expanded one after another.

However, when the first set is printed and the second set is printed in the electronic sort mode described above,
Since the page length of the last page of the first copy is not known, a large area is secured, and there is a high possibility that the expanded area cannot be taken even though the image of the second copy already exists (FIG. 13). Therefore, also in this case, the unnecessary area at the end of the first copy is released when the length of the document size is known, and is used as the area of the page to be expanded next.

Regarding the contents described above, the CPU 106
The control of the memory unit section 30 by means of will be described. During the copy operation, the start key 9 on the operation panel OP described above
After 6 is pressed, a series of sequences such as image reading and printing occur, but these are the same as the control of the conventional digital copying machine.
The processing of "reading", "compression", "expansion", and "output (print)" at 0 will be mainly described.

FIG. 14 is a flowchart showing the control operation main routine of the memory unit section 30. When the power is turned on, the internal state and various registers are first initialized (# 1). Then, read (Read), compression (C
ompress, Expand, Print status (Rea
d-busy, Compress-busy, Expand-busy, Print-busy) are initialized to "0"(# 2).

Continuing, communication processing with another CPU (command reception processing # 3, status transmission processing # 4)
After that, an internal job is generated according to the designation of various modes (# 5). In the generation of this job, each reading, compression processing (# 6), decompression processing (# 7), output processing (# 8), and other processing (# 9) are performed, and the processing is repeated from step # 3.

FIGS. 15 and 16 are flow charts showing the reading and compression processing routine (# 6). In this process, first, Read-busy indicating whether or not a read state is set is confirmed (# 6-1). If it is not in the read state, it is confirmed whether a read request is received (# 6-2), and if it is, it is confirmed whether the compression is completed (# 6-3) and Compre
If ss-busy is “0”, first two bands are prepared (# 6-4). At this time, since the reading has not started yet and the document size is unknown, the maximum width is prepared for the time being. (Here, as described above, an example of controlling in band units is shown.) Then, reading is started in one band (# 6-5). Read-bus that indicates the status because the read operation has started
The y is set to "1"(# 6-6).

If it is in the reading state in step # 6-1 (Read-busy is "1"), it is known that the reading process is in progress, so it is confirmed whether the reading has been completed (# 6). -7). The end of reading here is
Check the hardware status by reading the register. If it has been read (# 6-7,
YES), the vertical size detection process of the document is performed (# 6-
8). That is, in the document example shown in FIG. 6, it is confirmed whether the boundary of B can be detected. If it can be detected (# 6-9, Y
ES), it means that the trailing edge of the original has been detected, so that the compression of the current band is started (# 6-10) and the input is cut off (# 6-1) because the image gator D2 is no longer needed.
1) Reset the reading status (set Read-busy to "0") (# 6-12).

If the trailing edge of the document is not detected in step # 6-9, it means that the document has not been read up to the trailing edge, and the process is continued. It is confirmed whether the horizontal size of the document is fixed (# 6-13), and if not, the horizontal size of the document is detected (# 6-19). That is, in the document example of FIG. 6, the boundary of A is detected. If step #
If the document horizontal size has been confirmed in 6-13, it is confirmed whether the horizontal size of the band on the side opposite to the one from which the image is currently read is matched. If the horizontal size is not matched (# 6-14, # 6-14,
NO), if the band is not being compressed (# 6- 15,
No), the horizontal size of the band is changed (# 6-16).
The currently loaded band cannot be changed in horizontal size because it is not compressed yet.

Further, the input signal of the read image is switched to the band on the opposite side (# 6-17), and the compression of the current band is started (# 6-18). When the band compression is completed (# 6-20, YES), it is confirmed whether it is the last band of the page (# 6-21). If it was the last band (YE
S) Since the page has been compressed, the two bands are released (# 6-22), and the compressed state Compress-busy is set to "0" to clear it (# 6-23).

If it is not the final band (# 6-21, N
O), it is confirmed whether the horizontal size is fixed (# 6-24), and if the compressed horizontal size of the band is different, the horizontal size of the band is adjusted (# 6-25, # 6-26). FIG.
7 and 18 are flowcharts showing the decompression processing routine (# 7). In this process, Exp
Check and-busy, and if it is not in the expanded state (# 7-1, N
O), it is confirmed whether there is a decompression request (# 7-2), and if there is a request, the image to be decompressed is confirmed (# 7-3), and if there is, decompression is started.

It is determined whether the current mode is a mode in which a memory is secured in page units as described above or a mode in which band units are secured (# 7-4). If there is a rotation process here, the page mode is selected. In the page mode, if the horizontal size has been decided (# 7-5, YES), it is confirmed whether the vertical size has been decided (# 7-6). If the vertical size has been decided, it is set to that size (# 7-8), the maximum length if not determined (# 7-7). (If you don't need to change the horizontal size here, you don't need to check the horizontal size.) And check whether the page can be secured in the output image memory from the fixed size. (# 7-9), secure when possible (# 7-10), and start expanding there (# 7-).
11).

Also in the band mode, if the horizontal size is fixed, the horizontal band size is determined (# 7-12, # 7-1).
3), if not confirmed, set the maximum length (# 7-14),
Next, two bands are secured (# 7-15), and extension starts (# 7-17). When the decompression process ends (# 7-1
8) Check if all pages have been expanded (# 7-1
9) If so, cancel the expanded state (Expand-bu
Set sy to “0”. ) (# 7-20). I still have
If the mode is page mode (# 7-21, YE
S), adjust in the vertical direction (# 7-22 to # 7-24),
If it is in band mode, make a horizontal adjustment (# 7-2
6 to # 7-28), the expansion is started (# 7-25 or # 7-29).

19 and 20 show the output processing routine (#
It is a flowchart which shows 8). In this process, first, Print-busy indicating the output state is not "1" (not outputting) (# 8-1, NO), and if there is an output request (# 8-
2, YES), the output mode is confirmed and output is started (# 8-3). In the page mode, the document size is determined vertically and horizontally (# 8-4, YES), and output is started (# 8-8) when all pages have been expanded (# 8-5, YES).
The int-busy is set to "1" to keep outputting (# 8-9).

In the band mode, the horizontal size of the original is determined (# 8-6), and if the first band has been stretched (#
8-7, YES), and output starts at that point (# 8-
8, # 8-9). If printing is in progress (# 8-1, YE
S), and it is determined whether the output page mode is set (# 8-1).
0), Pr in the page mode if all output is completed
The int-busy is reset to "0"(# 8-12), and if the output is not completed, the process returns (# 8-11, NO).

In the band mode, all output is completed (#
8-13, YES), and Print-busy is cleared to "0"(# 8-17). If it's not over yet (# 8-1
(3, NO), wait for the output end state (# 8-1
4, YES), if there is a stretched band (# 8-1)
5, YES), the output band is switched (# 8-1)
6). Although one example of the embodiment has been described above, the document size detection direction described above can be applied in the vertical direction even when the document length cannot be determined until reading is started, such as a mixed document of a flow-through.

[0049]

As described above, according to the present invention, there is provided a digital copying machine having an image memory section for storing image data obtained by reading an original with an image reader, the image memory section having an original size. To provide a digital copier that can be used effectively together and that does not prolong the image compression time, and thus the extension time after compression, even when adopting a configuration in which the read image is compressed and retained. You can

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a digital copying machine according to the present invention.

FIG. 2 is a plan view of an operation panel of the copying machine shown in FIG.

3 is a block diagram showing a partial configuration of a control unit in the copying machine shown in FIG.

4 is a block diagram showing a configuration of a remaining part of a control unit in the copying machine shown in FIG.

5 is a block diagram showing a configuration of a memory unit section in the control section shown in FIG.

FIG. 6 is a diagram illustrating a normally conceivable state of an image input to an input image memory of a memory unit section.

FIG. 7 is a diagram showing a code management table in a RAM used for controlling a memory unit section.

FIG. 8 is an explanatory diagram of image rotation by a rotator of the memory unit section.

FIG. 9 is a diagram showing band division of the input image memory in the memory unit section and changing of the band lateral size according to the document size.

FIG. 10 is a diagram showing a control state of the output image memory in the memory unit section, which corresponds to the input image memory.

FIG. 11 is a diagram showing a band operation of an input image memory.

FIG. 12 is a diagram showing a band operation of an output image memory.

FIG. 13 is a diagram showing expansion area allocation control for the second copy print in the electronic sort mode.

FIG. 14 is a flowchart showing a main routine of a control operation of a memory unit section.

FIG. 15 is a flowchart showing a part of a reading and compression processing routine.

FIG. 16 is a flowchart showing the rest of the reading and compression processing routine.

FIG. 17 is a flowchart showing a part of a decompression processing routine.

FIG. 18 is a flowchart showing the remaining part of the decompression processing routine.

FIG. 19 is a flowchart showing a part of an output processing routine.

FIG. 20 is a flowchart showing the remaining part of the output processing routine.

[Explanation of symbols]

IR image reader 500 Automatic duplex document feeder (ADFR) PRT page printer OP Operation panel 100 Control unit 101-107 Central processing unit (CPU) 111-117 RAM 121-127 ROM 10 Image reader IR scanning system 11 Scanner 17 image Sensor 18 Platen glass 20 Image signal processing unit 30 Memory unit unit 301 Document size detection unit 302 Input image memory 303 Output image memory 304 Compressor 305 Decompressor 306 Code memory 307 Rotator D2 Image signal processing unit 20 to memory unit unit 30 Image data transferred to the D3 memory unit section 30 to the print processing section 40 60 print head 61 semiconductor laser 70A developing / transfer system 70B fixing / discharging system 80 paper transport system

Claims (3)

[Claims] 1. A digital copying machine equipped with an image memory section for storing image data obtained by reading an original with an image reader, wherein the image reader reads an input image memory area for storing input image data. Means for setting in the image memory unit corresponding to the maximum possible document size, and means for detecting the document size from the image data stored in the input image memory area. A unit for starting a size detection process, and a unit for changing the input image memory area set corresponding to the maximum document size in correspondence with the document size detected by the document size detection unit. Digital copier. 2. The image memory section is provided with an image holding memory area capable of holding a plurality of images, and means for transferring image data from the input image memory area to the image holding memory area is provided. When the document size is detected by the size detecting means, a storage image area in the input image memory area unnecessary for the detected document size is deleted and necessary image area data is stored in the image holding memory from the input image memory area. The digital copying machine according to claim 1, wherein the mode is switched to a mode of transferring to an area. 3. The means for setting the input image memory area in the image memory section sets the input image memory area in units of one or two or more bands, and the input image memory area is detected by the document size detecting means. 3. The digital copying machine according to claim 1, wherein the means for changing the size of the original to change the input image memory area for each band.