JPS61176287A - Picture processing system - Google Patents

Abstract

PURPOSE:To attain an effective abnormality measure even if an abnormality arises in the expansion of a compressed picture CONSTITUTION:A code 10-14 denotes a comparator and compares the up-count output M-ADR of a memory address counter 10-8 with.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an image processing system that processes images as electrical image signals.

Image processing such as converting an image into an electrical signal and transmitting or storing the electrical signal has been proposed.

By the way, in order to represent an A3 size image as a binary signal with a resolution of 400 dpi, an image signal of approximately 4 Mbytes is used. Therefore, in order to store this image signal, a memory having a storage capacity of at least the same number of bytes is required.

Therefore, it is conceivable to compress the image when storing the image. According to this, the amount of information in a typical image is 1/10
This means that a relatively small capacity memory can be used. However, the amount of compressed information is non-uniform depending on the image, and therefore the amount of information constituting one line is also not the same.

Therefore, when decompressing an image signal that has been compressed and stored in this way, for example, line synchronization must be maintained accurately, otherwise the decompressed image will be distorted. It is impossible.

The present invention has been made in view of the above points, and an object of the present invention is to implement an effective countermeasure against an abnormality even if an abnormality occurs in the expansion during expansion of a compressed image signal. , a decompression means for decompressing and outputting a compressed image inputted from the input means; a means for detecting an abnormality in the decompression operation of the decompression means; and a case where the detection means detects an abnormality in the decompression operation of the decompression means. , comprising means for outputting a previously expanded decompressed image signal with no abnormality in place of the decompressed image with the abnormality, and means for counting the number of times an abnormality has occurred in the decompression operation; DESCRIPTION OF THE PREFERRED EMBODIMENTS An image processing system is provided in which the decompression operation of the decompression means or the output operation of the decompressed image is stopped when the decompression means exceeds a predetermined number.

FIG. 1 shows an image processing system to which the present invention is applied, including an image reading device (hereinafter referred to as reader) 1-1, an image storage device (hereinafter referred to as RMU) -2, and an image forming device (hereinafter referred to as printer). It consists of 1-3.

The main functions include a copy function that forms an image on the printer 3 from the image signal read by the reader 1-1;
There is a memory input function for storing the image signal read in RMUI-1 in RMUI-2, and a memory printout function for forming an image in printer-3 from the image signal stored in the memory of RMUI-2.

Each device is connected by a video interface, which will be described later.

As shown in FIGS. 2 and 3, the reader 1-1 uses a CCD line sensor 3-1 having a light-receiving element of about 5,000 bits, for example, to separate the document on the document table 2-1 into a plurality of pixels, line by line. bit serial binary image signals VDA and VDB indicating the density of the original image are output. In FIG. 2, the reading of one line by the CCD 3-1 is main scanning reading 2-2, and the movement of the main scanning reading line in a direction substantially perpendicular to the main scanning direction is sub-scanning 2-3.

Figure 3 is a simple configuration diagram of the reader.
A CCD licensor 3-1 converts reflected light obtained from an original by an illumination system (not shown) into a bit-serial image electrical signal for one main scanning line. CCD3-1
An analog image electrical signal corresponding to the intensity of reflected light from the original document is digitized by the A/D converter 3-2 into a multi-bit digital image signal for each pixel. The digitized image signal is sent to a binarization comparator 3-3.
3-4, the binarized threshold signals generated from the threshold generators 3'-5 and 3-6 are compared with each other, and one of the two systems is
It is output as binary image signals VDA and VDB.

Assuming that the input analog image signal is converted into a 6-bit digital image signal by the A/D converter 3-2, 64 density levels having values from 0 to 63 are obtained. For example, set the threshold value from the threshold value generator A3-5 to 42
, assuming that the threshold value from the threshold value generator B5-6 is 21, the binarized image signals VDA and VDB from the binarized comparator 3-3, 3-4 are as follows.

That is, the output from the A/D converter 3-2 is O~2
If the output from A/D converter 3-2 is 21 to 41, VDA=O, V
DB=1, output from A/D converter 3-2 is 42~
In the case of 63, VDA=1 and VDB=1, and the image signal from the original has three states VDA and VDA depending on its reflection density.
=O, VDB=0, VDA=O, VDB=1, VDA=
1. It is represented by VDB=1. Therefore, the image signal is output from the reader in three values for each pixel. Note that it is also possible to make the threshold values from the threshold value generator A and the threshold value generator B equal, so that a binary image signal is output. Furthermore, the threshold comparators 3-5 and 3-6 can also generate dither matrix thresholds using the conventional well-known systematic dither method, and thereby it is also possible to express halftones with ternary image signals of VDA and VDB. It is.

RMUI-2 in FIG. 1 is an image storage device as described above. The inside includes a compression circuit 1-2-1 that compresses the image signal from the reader by encoding, a compressed image memory 1-2-2 that stores the encoded image signal, and a compressed image memory 1-2- An expansion circuit 1- reads out the compressed image signal of No. 2, decodes it, and expands it into a bit serial image signal.
It consists of 2-3.

The printer 1-3 is a laser beam printer using a well-known electrostatic recording process, and a schematic diagram thereof is shown in FIG. In FIG. 4, 4-1 is a photosensitive drum that rotates about a predetermined axis, 4-2 is a laser driver that converts an image signal into ON/OFF laser light, and 4-3
4-4 is a polygon scanner that scans a laser beam emitted from a laser driver 4-2 in the axial direction of the photosensitive drum 4-1, and 4-4 scans an electrostatic latent image on the photosensitive drum 4-1 formed by scanning the laser beam. Development unit that develops toner)
, 4-5 is a print paper cassette, 4-6 is a print paper pickup roller that pulls out the print paper one by one from the print paper cassette 4-5, and 4-7 is a print paper pickup roller that picks up the print paper one by one from the print paper cassette 4-5. 4-8 is a transfer unit that transfers the toner image on the photosensitive drum 4-1 onto the print paper; 4-9 is a fixing unit that fixes the toner image transferred to the print paper on the print paper; -10 is a paper discharge tray from which the print paper on which the toner image has been fixed is discharged.

The operation in which an image signal, which is an electrical signal, is realized on print paper in a printer will be described with reference to FIG. The two systems of binary image signals vDA and VDB input from the video interface 5-11 are sent to the synthesis circuit 5-1.
0, it is synthesized into three values (VD signal) and the laser driver 5-
3 and is converted into laser light by a semiconductor laser 5-4 based on the VD signal. The laser beam is focused by a collimator lens 5-5, and scanned by a polygon mirror 5-6 in a direction substantially parallel to the rotation axis of the photosensitive drum 5-2, which is rotated by a predetermined amount. The scanned laser beam is f-
The scanning position is corrected by the θ lens 5-7, and the photosensitive drum 5
-2 to form a latent image based on the VD signal.

Image formation in the printer uses a so-called electrostatic recording method, in which a necessary portion of the charge applied to the photosensitive drum 5-2 is removed using a laser beam, and then a developing process is performed using a developer. This is done by transferring and fixing onto printing paper.

Since the electrostatic recording method is a well-known technique, detailed explanation will be omitted.

Now, the laser beam scanned by the polygon mirror 5-6 is incident on the optical fiber 5-8 before being irradiated onto the photosensitive drum 5-2, and when the photodetector 5-9 detects the incident, an electric signal ( Outputs BD double signal.

The image signal output device waits the time from when the BD double signal is generated until the laser beam reaches the photosensitive drum 2-2, and then outputs the V'D signal.
If the signal is output, a latent image will be formed at an appropriate position on the photosensitive drum 2-2.

The interface that connects the devices shown in FIG. 1 is called a video interface, and FIG. 6 shows its schematic diagram.

The video interface is an interface that connects the image output device 6-1 and the image reception device 6-2.A typical example of the image output device is the above-mentioned reader, and an example of the image reception device is a printer. The image storage unit (RMU) 1-2 in FIG. 1 is positioned as an image receiving device for the reader 1-1, and as an image output device for the printer 1-3.

As mentioned above, the video interface transmits the bit-serial image signals VDA and VDB, as well as the line synchronization signal BD from the image receiving device as a signal that controls the image signal, and the output image signal for one page from the image output device. A synchronization signal consisting of VSYNC, which is a section signal, video input (vE), which is a one-line section signal, and image clock VCLK, is transmitted.

These image/image synchronization signals have the phase relationship shown in FIG. 7, and when the image output device receives the BD double signal, the BD signal shown in FIG.
After counting the time (left margin) from the light receiving end of the optical fiber 5-8, which is the signal generation position, to the image effective area of the photosensitive drum 5-2, one line worth of image signal VDA is obtained.

Outputs VDB and section signal ■E. Signal VE.

VDA and VDB are synchronized with the image clock VCLK, and in the printer, VDA and VDB are synchronized with the clock VCLK.
In synchronization with , the recorded image VD is synthesized into three values and transmitted to the laser driver.

Furthermore, the video interface has a connect signal (DCNCT) for each device as a control signal representing control information.
, a power ready signal (DPll, DY) indicating that the control unit of each device is operating normally, a signal (PREQ) indicating that the image receiving device is ready for output paper feeding, and an output paper feeding signal from the image output device. A paper signal (PRINT) and an image request signal (VSREQ) from the image receiving device are transmitted. The control signals still include information on the paper size of the printer's paper feed stage, the connection status of various devices, detailed error information, and the like.

FIG. 8 shows a list of names, abbreviations, transmission directions, signal classifications, and contents of various signals transmitted through the video interface.

The outline of the components in this embodiment has been described above, and based on that, 11. Image encoding in MU 1-2 will be explained.

The image signal from the reader is bit serial image information, so it is 400 dpi (400 dots per inch).
Image information read at a resolution of 3. on an A31 page.
The memory capacity is 7MB. This is image information equivalent to 574 images in a 64-bit DRAM, which is impractical both in terms of implementation and price, so the image is compressed and encoded and stored in the memory 1-2-2.

The image information from the reader is compressed and encoded by the image compression section 1-2-2, and in this embodiment, the run-length method is used for encoding. The run-length method uses ° of the image signal.
The result of counting the number of consecutive 1''' states or 0'' states by a counter is handled as an image signal, and the format of run length encoding in this embodiment is shown in FIG.

The format of the run length code in this embodiment is composed of 1 byte (8 bits) as shown in (9-1), and the encoded data of the image is expressed in a 7-bit binary format in bat6 to bit O.

Furthermore, in the 7-bit binary format, the run length (consecutive number of 110 bits) can only be expressed from O bits to 127 bits, so if the run length is 128 bits or more, it is expressed in a 2-byte configuration. In this case, one of the two bytes becomes a make-up code (hereinafter referred to as M code) representing a run length that is an integral multiple of 128 bits, and the remaining one
The byte becomes a termination code (hereinafter referred to as T code) representing a fraction from 0 pit to 127 bits. In order to distinguish between the makeup code and the termination code, bit 7 is used as an identification flag, as shown in (9-1), where 1 indicates the M code and 0 indicates the T code.

The run length encoding of this embodiment is performed when the image signal 4677 pits of one line corresponding to the main scanning length of 297 mm of an A3 size document is composed of a black and white pattern of 5 consecutive bits of the white signal and 4672 consecutive bits of the black signal. will be explained using an example.

In the run-length method in this embodiment, the first 5 white bits appearing are encoded using a T code as in (9-3). The next 4,672 bits of black that appear are 128 or more, so they are composed of an M code and a T code. The M code is a binary representation of 36, such as '(9-4), and the T code is ('9-5 ), 64 is expressed in binary form. That is, it is encoded as M code (128×36)+T code (64)=4672. As explained above, the above-mentioned 4677-bit one-line image signal is expressed by three bytes (9-3), (9-4), and (9-5).

Furthermore, an EOL code (End of Line -y-code) shown in (9-2) is used as a signal to separate one line. This EOL code looks like an M code because bit 7 is 1, but in the M code bit 6
If bit O is all 1, it means a continuous 16256-bit image signal. In this example, the maximum data length of one line is 4677 bits, and since bit 6 is always O in the M code, an M code in which all bits are 1 is generated by normal run-length encoding. There is no such thing, and the EOL code and M code are clearly distinguished.

Adding the BOL code to the above white 5 bit black 4672
One line of image signal of 4677 bits is written into the memory as 4-byte data, which is about 1/146 of the original signal. Note that this encoding method does not have data indicating whether it is white or black in the code. Instead, 1
Line data always begins with a white code. The T code is also used as a code indicating data change from white to black and from black to white. If one line starts from black, a T code O representing white O is added in front of the black code. Furthermore, even if the sequence of images is exactly an integer multiple of 128 and can be encoded using only the M code, a T code O representing white 0 is added to indicate that the color changes.

This embodiment will be described in detail with reference to FIG. 10.

Figure 10 is a diagram showing the detailed structure of Table 1, and is 40-1.
The leader of 10 becomes the leader of 1-1 in Figure 1.
-3 printer is connected to 1-3 printer, 10-4 compression circuit is connected to 1-2-1°, 10-5 compressed image memory is connected to 1-2-2, and 10-6 decompression circuit is connected to 1-2-2. 1-2-3 respectively. 10-2 is a controller, which is composed of a microprocessor and a peripheral I10 boat device, and is responsible for serial communication with the reader 10-1 and printer 10-3, input/output of various video interface control signals, control of selectors inside the RMU, It has functions such as setting constants to counters, comparators, etc., generating various timing signals, and capturing the internal state of the RMU.

The compression circuit 10-4 is a circuit that compresses the image signal from the reader 10-1 line by line using the run-length method described above.

A compressed image memory 10-5 writes the run-length code generated by the compression circuit 10-4, and also supplies the read code to the decompression circuit 10-6.

The decompression circuit 10-6 is a circuit for decompressing the compressed image memo I710-5 color run length code into bit serial image data.

10-7 is an EOL code detection circuit that detects EO that occurs during decompression.
Detects L errors, repairs EOL errors, and reduces images in the sub-scanning direction during decompression by skipping EOL codes. Further, the EOL detection circuit is a circuit that operates only when the sub-scanning extension period signal V-DEC from the controller 10-2 is asserted, and when the signal V-DEC is negated, the EOL detection circuit 10-7 Buffer change enable (Buff CHG B
NB ) signal and data enable /L/ (Data E
NB ) signal is fixed at high (H) level, DH, P
2 signal is fixed at low (L) level.

A memory address counter 10-8 performs an up-count operation to address the compressed image memory 10-5. This counter is configured such that a write/read start address can be set by the controller 10-2, and further, the counter output can be read by the controller 10-2. The count clock of this counter 10-8 is the compression circuit 10-4, the expansion circuit 10-6, and the E
The DWP signal, DRPI signal, DR, and P2 signals from the OL detection circuit 10-7 are applied through the NOR gate 10-29.

10-10 is a dither counter having the configuration shown in FIG. The dither counter in this embodiment is composed of a 3-bit down counter 13-1, a 10-bit down counter 11-2, and a 10-bit comparator 13-3.

Two down counters, 11-3 and 13-2, totaling 13.
A bit address signal DADR is supplied to double buffer memories 10-15.

10-11 is a line counter, controller 10-
2, and when the counting is completed, a signal is generated to the controller 10-2.

10-12 is a main scanning counter and a decoder which generates the compression/expansion section signal H-AREA for each line, and the start signals DC8TA and BT of the dither counter 10-10.
, generates an address (HADR) to the double buffer memory 10-15, and a signal (T) for trimming the image signal from the double buffer memory 10-15.
R, M) is generated. FIG. 12 shows a detailed configuration of the main scanning counter and decoder 10-12.

In FIG. 12, 14-1 is a 13-bit down counter whose count start value is set by the controller 10-2, and starts counting upon input of the 5TART signal.

14-2 to 14-8 are 13-bit comparators, each of which generates an A=B output when the value of the counter 14-1 becomes equal to the value set by the controller.

14-10 to 14-12 is 14- with flip-flop
It is set and reset by the outputs of comparators 2 to 14-7.

A comparator 10-14 compares the up-count output M-ADR of the memory address counter 10-8 with the set value from the controller 10-2. Comparator 1
The controller 10-2 controls the memory address counter 10-8 by the signal MOVER which is the A≦B output of 0-14.
It is detected that the force has reached the eight force value of the comparators 10-14. Also, in this state, the MOVER signal is in logic state 1 (
(hereinafter referred to as H level), the CLK input of the memory address counter 10-8 becomes the NOR game)10-
30, and the count-up operation of the memory address counter 10-8 is stopped.

Reference numeral 10-15 is a double buffer memory consisting of memory X and memory Y each having one line worth of memory, and the memories X and Y have reverse read and write operations. This buffer switching is performed by inputting the BuffCHG signal, and the read address signal and write address signal are input from the DAD from the dither counter 10-10.
R and HAD from main scanning counter decoder 10-12
R, is used from time to time.

10-16 is an internal clock generator that generates a video clock for outputting the expanded image signal to the printer;
A clock ICLK is generated in synchronization with the 8YNc signal.

Reference numeral 10-17 is a horizontal synchronizing signal generating section which outputs an IBD signal having approximately the same frequency as that of the BD input from the printer via the video interface. If the BD double P-BD specified by the video interface is not input from the printer 10-3, the IBD signal is input to the selector 5EL5.
By selecting at 10-22, it is used as the main scanning synchronization signal H8YNC inside the RMU and BD double signals R and -BD to the reader.

10-18 is a selector for the φsYs clock, which selects the video clock R-VCLK from the reader and the -CLK from the internal clock generator 10-16 according to instructions from the controller "10-2."

10-19 is a selector for writing data to the double buffer memory 10-15, which selects the image signal R-VDA from the reader and the expanded image signal DV from the expansion circuit 10-6.
DO is selected according to instructions from controller-10-2.

10-20 is a selector for the LN-8T signal which is used as a count start signal for the main scanning calanta decoder 10-12 and a clock input for the line counter 10-11, and selector 5 selects the H8YNC signal from EL510-22 and the R-VE from the reader. The selection is made according to instructions from the double signal controller 10-2.

10-21 is the selector for E double signal P-VE that goes to the printer, and connects the OVE signal corresponding to VE from the main scanning counter decoder and the VEm number R-VB from the reader)
Select according to instructions from o-ler-10-2.

10-22 is the <H8YNC selector as described above,
The selection is made according to instructions from the controller 10-2.

10-231'l: Controller 1 with selector for image signals P-VDA and P-VDB output to printer 10-3
Controlled by 0-2. Image signal R-VDA from the AO and BO large input beamers of the video selector 10-23
is connected, and by selecting the AO and BO large inputs, the image signals to the printer are connected. When the R-VDA from the reader is connected to both P-VDA and P-VDB, the image signals are output to the printer. As is clear from FIG. 7, the recorded image VD becomes a binary image.

When A1 manual power and B1 manual power are selected in the video selector 10-23, the image signal R-VDA from the reader is output as the image signal P-VDA going to the printer, and
A signal obtained by further passing the image signals R and -VDB of the readers through an AND gate 10-34 is output to -VDH.

The other input signal R- of the AND gate 10-34 with
HALF is a signal from controller 10-2.

If this R-HALF is at H level, the image signal P-VDB going to the printer is the image signal R-VDB from the reader.
The recorded image VD output to the printer is the same signal as the image signal R-VDA from the reader as shown in FIG.
, R-VDB are combined into an image.

If the R, -HALF signal is in the logic state O (hereinafter referred to as "L level"), the image signal P-VDB going to the printer is L.
fixed at the level. Therefore, as shown in Fig. 7, the image signal VD output to the printer has a duty of about 50% for one pixel (one video clock) section.
The signal is recorded on the output paper. This means that when the R-HALF signal is at L level, the lighting time of the laser beam emitted from the laser unit 5-4 is about half that of when it is at H level, and the R-HALF signal is at L level. By doing so, an output image density of approximately 50X of the image signal from the reader can be obtained.

When A2 manual input and B2 input are selected with the video selector 10-23, the image signal going to the printer P=VDA is an AND game of the output from the double buffer memory 10-15)
10=27.The signal passed through 10-28 becomes RMU-VD. Also, the image signal P-VDE signal RM going to the printer
The signal is passed through U-VD'l et KAND game) 10-32. The other input of this AND gate 10-23 is a signal from the RMU-HALF controller 10-2, and if this RMU-HALF signal is at H level, the image signal P-YDB going to the printer is the same as P-VDA. The recorded image VD outputted to the printer with the same signal becomes a binary image based on the image signal RMU-VD, as shown in FIG. If the RMU-HALF signal is at L level, the image signal P-VDB going to the printer is fixed at L level. In other words, the P-VDA has a double buffer memory 10-
The image signal RMU-VD from 15 is transmitted, but the image signal RMU-VD from P-
Since VDB is up to L level 1, the image signal VD output to the printer is 1 pixel (1
The image signal is recorded on the output paper as an image signal with a duty of about 50% for the video clock section. This is RMU, H
When the ALF signal is at the L level, the O of the laser light emitted from the laser unit 5-4 is lower than when the ALF signal is at the H level.
This means that N time is approximately halved, and RMU-HALF
By setting the signal to L level, an output image density of about 50X can be obtained.

When A3 manual power and 83 manual power are selected by the video selector 10-23, the image signals P-VDA and P-VDB sent to the printer by the action of OR gates 10-31 and 10-32 are converted to the image signal R-VDA from the reader. , R-VDB and the image signals R, MU- of the double buffer memory 10-15
It is a composite of VD. Therefore, the above-mentioned R,-HAL
Table 1 shows the image signal VD output to the printer by arbitrarily combining the F signal, R, and MU-HALF' signals.
become that way.

10-25 is the Buff from the EOL detection circuit 1o-7
CHG ENB signal (double buffer switching permission)
3-person AND that gates the LN-8T signal and generates the switching signal Buff CHG for the read buffer and write buffer of the double buffer memory 10-15.
It is a gate.

1o-3s is a decompression error counter that counts the number of lines in which decompression errors occur by the decompression circuit 10-6.

The basic functions of this embodiment configured as described above are as follows.

(1) (Binary compression) Image signal R-V with fixed threshold from reader 10-1
Perform binary compression processing on any part of DA to create a compressed image memo I7
A function to write to 10-5. Incidentally, this is also applied to the case where the image signal of the entire area of the document is written to the memo IJ 10-5.

(2) (Dither compression) A function to perform dither compression processing on an arbitrary part of the image signal R-VDA according to the dither matrix threshold value from the reader 10-1 and write it in the compressed image memo I710-5.

(3) (Binary decompression) The binary compressed image stored in the compressed image memo IJ 10-5 is read out, subjected to binary decompression processing, and sent to the printer 10-3.
Function to output to.

(4) (Dither expansion) The dither compressed image stored in the compressed image memory 10-5 is read out, subjected to dither expansion processing, and then sent to the printer 10-3.
Function to output to.

Hereinafter, specific operations will be explained in order.

(1) Binary compression function The image signal input from the reader is transmitted as a VE multiplied signal synchronization signal representing one main scanning line as shown in FIG. A sub-scanning section for one page is expressed by the VSYNC signal. This VB multiplied signal in FIG. 10 is expressed as an R-VE multiplied signal.

The image compression method in this embodiment encodes image data only in the main scanning direction, and does not perform image compression in the sub-scanning direction.

Below, the image information A of A3 size (main scan 297 mm (corresponding to 4677 bits), sub scan 420 mm) with a resolution of 400 dots/1 nch (400 dpi) transmitted from the reader as shown in Figure 13 is transferred to the main image. An example will be explained in which image information B of 140 mm x 210 mm is trimmed and binary compressed from a point after 7 Q mm in the scanning direction and 100 mm in the sub-scanning direction.

Before receiving the above image data from the reader 10-1, the controller 10-2 sets the mode of each part inside the RMU.

Image signal R-VDA sent from reader 10-1
Clock 5S used inside RMU to compress
Clock R-VCL from reader 10-1 as YS
Select K and set slide 1O-18SEL1.

Image signal R-VDA1 input from reader 10-1
The data is stored line by line in the d-tuple backup memory 10-15, and its output is input to the compression circuit 10-4. Therefore, 1o-19SEL2 is set so that the image data input to the double buffer memory 10-15 is 几-VDA.

Next, set the synchronization signal Ll'1-8T for each line, but this should use the R-■E times signal from the reader 10-1 (set 10-208EL3. Also, the reader 10-1 As a synchronization signal to generate R-VB,
As mentioned in the explanation of the video interface that the l'IBD signal is required, 1O-22SEL5 is set to output the IBD signal from the horizontal synchronization signal generator 10-17 as an R-BD multiplied signal. .

Next, a count start value of 4677 is set in the down counter 14-1 of the main scanning counter/decoder 10-12 so that 4677 bits of image data for one line can be controlled.

Comparator 1 sets the main scanning direction of area B in Figure 13.
Performed on 4-4 and 14-5. That is, the H-AR, EA double signal compression circuit 10 from the flip-flop 14-11 is set and reset by the outputs of these two comparators.
-4, and the compression circuit 10-4 performs run-length encoding processing on the image data during the main scanning period when this signal is at H level, and writes it into the compressed image memo IJIO-5.

Therefore, the comparator 14-4 is set to the value 3575, which is obtained by subtracting 1102 bits, which corresponds to the 70 mm margin in the main scanning direction up to the area B in FIG. 13, from 4677. Also, the comparator 14-5 has 14Qm during main scanning of area B.
The value 1371 is set by further subtracting 2204 bits that are consistent with m from 3575.

The output DO8TAB'I' from the comparator 14-8 starts the dither counter 10-10, and the down counter 14-1 and the dither counter 10-1
In order to operate 0 at the same time, 4677 is set in comparator 14-8.

The following constants are set for the dither counter 10-10. In other words, in order to set the count start value 4677 in the counters 13-1 and 13-2 and perform binary compression]
) i Set the fhe signal to L level. Thereby, the dither counter 10-10 performs the same operation as the down counter 14-1.

With the above constant settings, double buffer memory 10-15
Two addresses DADR, given to .

Both HADR is 4677 due to R-VE double signal rising.
There will be a countdown from.

That is, the double buffers 10-15 and the compression circuit 10
The image signal EVDO given to -4 is a signal that is exactly one line behind the image signal R-VDA from the reader.

Expansion circuit 10-6. Since the expansion start signal V-DEC given to the EOL detection circuit 10-7 is at L level, the DB
, PI signal DRP2 signal is L level, Buff
The CHG ENB signal and DataBNB signal become H level, and the expansion circuit 10-6°EOL detection circuit 10-7
It is configured so as not to affect the compression operation.

Further, a write start address to the compressed image memo IJIO-5 is set in the memory address counter 10-8.

In this state, controller 10-2 receives V from the leader.
Wait for SYNC to be input. When VSYNC is input, the controller 10-2 sets 1574 lines corresponding to 100 mm in the line counter 10-11 in order to count the sub-scanning length of 100 mm up to area B in FIG.

The line counter 10-11 counts down in response to the LN-8T signal, that is, when the main scanning section signals R and -VE from the reader are input 1574 times, the line counter 10-11 sends the count up signal to the controller 10.
-2, the controller detects that the image signal from the reader has entered area B. Thereby, the controller should cause the compression circuit 10-4 to start compressing the image (
While changing V-BNC from L level to H level,
In order to measure the sub-scanning length of the area of 210 mm, 3307 corresponding to 210 mm is set in the line counter 10-11.

When the R-■E double signal of 3307 lines for the B area is input from the reader, the line counters 10-11 count up again, and the controller 10-2 detects the disconnection and changes the V-BNC signal from the H level. The signal is set to L level to stop the image data compression operation of the compression circuit 10-4.

In this way, the image signal R-VDA that is continuously input from the reader 10-1 has an arbitrary interval in the main scanning direction where H-AREA emitted from the main scanning counter decoder 10-12 is at H level, and is still in the sub-scanning direction. Controller 1 in the direction
The V-ENC issued by 0-2 is encoded by the compression circuit 10-4 while being tuned to an arbitrary section of H level, and written to the compressed image memo IJIO-5.

This situation is shown in Figure '14. R-V in Figure 14
DA shows an example of inputting an image signal of one line, in which 2 bits of white, 2204 bits of black, and 5 bits of white are input as image signals in the trimming area of a certain line. A 5-byte run length code is generated in the compression circuit 10-4 by this R-VDA input. In other words, the first white 2 creates a 2H T code,
Next, with black 2204, M code 91H, T code 15H
1 The last white 5 gives the 5H T code, and then GH-AR
An EOL code is generated due to the end of EA, and compression circuit 1
The data is written into the compressed image memory 10-5 by the write request DWP pulse from 0-4.

A memory address counter 10-8 addresses the compressed image memory 10-5, and is counted up by a signal from which the DWP pulse passes through the gates 10-29 and 10-30.

If the image signal R-VDA from the reader changes drastically and a large amount of compressed codes MW codes are generated, a situation arises in which all the compressed codes MW codes cannot be written in the compressed image memo IJIO-5. Furthermore, when writing multiple pages of compressed image data to the compressed image memo January 0-5 as shown in Figure 15, a part of the previously written compressed image data T is newly written. A situation arises in which the image data U is corrupted. In this embodiment, when writing compressed image data, it is detected that the writable free area has been exceeded, and in order to protect other compressed data, comparators 10-14 are used to monitor the memory usage status.

In FIG. 15, compressed image S (end address SE) and compressed image T (start address TS) are stored in compressed image memory.
) is stored, address 8E and address T8
When writing the compressed image U between the controller 10-
2 is a memory address counter 10-8 which calculates the write start address US based on the end address SE of the compressed image S.
The start address TS of the compressed image T is set in the comparators 10-14 as an address limiter. When the write progresses and the count output of the address counter 10-8 reaches the TS value of the comparator 10-14, the comparator outputs A≦B, and a new write request pulse is generated at 10-30. DWP is gated, the memory address counter is stopped, and further write operations are prohibited. This protects the compressed image T. Controller 10-2 still receives A from comparator 10-14.
≦ Upon receiving the MOVER signal which is the B output, it is detected that the compressed image could not be completely written to the memory 10-5, an image compression error is detected, the memory area where the image data could not be written is set as an empty area, and the image is stored in the memory. output is prohibited, and a message to that effect is displayed on the reader display section.

The controller 10-2 moves when image compression is completed.
If the r signal is determined and it is detected that the Mover signal is not generated, it is determined that the image compression writing has been successful, the address output MADR from the memory address counter 10-8 is read, and the currently written compressed image is terminated. This address is stored in the controller's internal memory and used to set the start address for writing the next compressed image.

Similarly, the controller also holds the write start and end addresses set in the memory address counter 10-8 and uses them when decompressing and outputting compressed image data.

Note that when the image of the entire document is encoded and stored in the memory, the trimming area may be set to the document size.

(2) Function of dither compression When the image signal input from the reader 10-1 is expressed in halftones by systematic dithering, the image changes drastically, and in the main scanning direction as used in this embodiment. It is difficult to perform effective image compression using an image compression method that encodes the continuity of images.

In this embodiment, the periodicity of the dither pattern is utilized to effectively compress the dithered image signal.

In FIG. 16, the dithered image signal is (16-
1) is input from the reader 10-1. In this example, an 8×8 dither matrix is used per block.The details are (16-2)
Suppose that the image signals read from the reader are uniformly divided into 3
If it is of level 2, a black signal will be output where the threshold value of IJ (Dazama) is 32 or more, and
An image as schematically shown in (16-1) is obtained using the dither matrix of (6-2).

(16-2) is an image signal obtained by enlarging only four blocks in the main scanning direction from the image signal (16-1).

Here, the main scanning line signal indicated by H is R of (16-4)
As for the VDA signal, 18 state changes occur during 4 blocks. The number of state changes is proportional to the number of blocks, and for A4 size 297 mm, 1168 state changes occur.With silan length encoding, 91170
The amount of encoded data is in bytes. This 1170
Byte//'i is approximately twice the amount of data as the original image amount of 4677 bits, which results in an increase in the amount of image information.

Therefore, by extracting the image signal obtained from the H line of (16-2) and the image signal processed with the same threshold value as shown in (16-3) and rearranging them in block order, between the blocks ( As shown in EVDO 16-4), the state changes twice. In other words, as shown in (16-3), signals based on the same threshold value for each block have little variation in black or white status, so arranging them consecutively can improve the continuity of the image. become.

In this embodiment, the rearrangement of the image signals according to the dither matrix is performed by controlling the reading of the double buffer memories 10-15 using dither counters 1.degree.-10.

Dithered image signals RVDA from the readers are written into the double buffer memory 10-15 in the order of input by the readers under address control of the main scanning counter/decoder 10-12.゛In this embodiment, since the main scanning of the dither pattern is repeated at 8-bit intervals, the dither counter 1
When reading image data from the double buffer memory 10-15, 0-10 is counted down at 8-bit intervals and read out. This 8-bit interval reading is performed from the controller 10-2 shown in FIG.
r signal. Also controller 10
-2 sets the value obtained by subtracting N-1 from the counter setting value of 13-2 to the comparator 13-3 according to the number N of main scanning compression blocks shown in (16-1). This number of compressed blocks N corresponds to the length of the H-A RE A signal indicating the main scanning compressed data length given to the compression circuit 10-4 (H
-AREA signal bit length)=N×8.

l) In Fig. 11, when the i ther signal goes to H level, the 3-bit counter 13-1 and the 10-bit counter 13-2 are separated, and the counter 13-2 counts down and is set in the comparator 13-3. When the number of blocks N is counted, A=B of comparator 13-3
An output is generated, counter 13-2 is reloaded to the original set value, and counter 13-1 counts down by one.

That is, the counter 13-2 counts the number of blocks N, and the counter 13-1 specifies which threshold value in each block the image signal is based on. In this way, the main scanning block length of the dither matrix can be arbitrarily selected by the comparator 13-3, and can correspond to dither compression of an image signal having an arbitrary length in the main scanning direction.

(3) Binary image decompression function This is a function of decompressing the binary compressed image mentioned in (1) and outputting it to the printer 10-3, which allows the decompressed image to be trimmed and moved.

First, in order to explain basic binary image decompression, we will assume that no trimming or movement processing is performed, and the compressed image signal from area B in FIG. As an example, assume that the compressed image is stored in area B and outputs the compressed image to area B of an A3 output sheet having the size of area A.

Prior to outputting the expanded image of area B, the controller 10-2 causes the printer 10-3 to feed A3 output paper in advance in order to create a margin of 100 mm at the leading end in the sub-scanning direction. That is, in FIG. 4, the printer is configured so that the distance from the transfer position of the photosensitive drum to the laser-exposed point a is equal to the distance from b to the registration paper feeding point C-1. The A3 output paper is sent out using the registration roller 7, and after the sub-scanning paper is fed by 1QQmm, the expansion operation is started, and the 8 images shown in FIG. 13 are output. Therefore, after the controller 10-2 outputs the registration paper feed signal vSYNC to the printer, the line counter 10-1
Set the number of lines corresponding to 100 mm to 1. This value reaches 1574 lines at a resolution of 400 dpi.

The line synchronization signal LN-8T during image expansion is 5EL3 of 10-20. BD doubling P'-BD from the printer is selected by SgI and 5 of 10-22. The internal clock +2'sys is still selected by 5EL5 of 1.0-22.In synchronization with H8YNC, the internal clock generator 10-
The I-CLK generated at 16 is selected at 5BLI at 10-18.

Now, with the line counter 10-11 mentioned above, the sub-scanning margin I is
When the controller finishes counting 1574 lines equivalent to Q Q mm, it outputs the image expansion signal V-DEC and starts the expansion operation of area B, but before that,
The address value set in the memory address counter 10-8 at the time of image compression storage is set in the comparator 10-14, and the final MADR value at the time of compression is set in the comparator 10-14.

The decompression circuit 10-6 decompresses the image line by line in response to the VDEC signal from the controller 10-2, and the decompressed image signal DVDO is written into the double buffer memory 10-15, and after one line, is output to the printer. At this time, the dither counter 10-1.0 functions as a write address counter for the double buffer memory 10-15, and the main scanning counter decoder functions as a read address counter.

The image expansion operation for one line will be explained below with reference to FIG. Assuming that the OVE signal as a video enable signal for the printer becomes H level when the value of HA D R is A, the down counter 14-1 of the main scanning counter decoder 10-11 has a value corresponding to the left margin amount described above. A+LMG considering the value LMG (173 bits)
.

A is set in the comparator 14-2. A-4676 for comparator 14-3, comparator 14-4
A for comparator 14-5, A-2203 for comparator 14-5, B for comparator 14-6, and B for comparator 14-7.
A is set in the comparator 14-8 so that when the -2203° counter 14-1 reaches A, the dither counters 13-1 and 13-2 start operating. Further, the dither counters 13-1 and 13-2 are set to A as a load value so that they perform the same counting operation as the counter 14-1.

When the PBD signal is input from the printer 10-3, LN-
'ST signal is generated, main scanning counter decoder 10-1
2 HADR, counts down from A+LMG, counts the clock to LMG, and when HADR reaches A, OV
E signal, HAR, and EA multiplied signal DC8'l''AR'r signal are generated.

This LMG is the number of clocks corresponding to the main scanning length from the BD sensor of the printer to the effective image area of the photosensitive drum, and the image signal output to the printer during the H level section of the OVE signal is printed on the output paper. Ru.

After HADR becomes A, when HADR becomes B after counting 1102 clocks corresponding to the 7Qmm margin up to area B in Figure 13, the TRM signal becomes H level and output from the double buffer memory. The image signal is enabled by Game) 10-27, and HADR is enabled by B-10-27.
22,03, the printer has 1 during main scanning in area B.
2204 pixels corresponding to 40mm are output and TRM
The signal becomes L level, and the subsequent image signals going to the printer are invalidated by game) 10-27. The expanded image signal stored in the double buffer memory in this way is output to the printer, but the double buffer memory 10-15
Writing an expanded image DVD to is as follows.

H-AR is applied to the expansion circuit 10-6°BOL detection circuit 10-7 at the same time as 0■E rises.

The BA double signal becomes H level and the expansion circuit 10-6 starts expanding the compressed image MR code.

The decompression circuit 10-6 reads the compressed image MR code from the section compressed image memo IJ 10-5 in which the sub-scanning decompression period signal V-DEC and the main-scanning decompression period signal H-AREA are at H level, and stores the code in a decode counter (not shown). Ink, l
A decompressed image DVD is generated by counting down with the 5Ys clock. That is, as shown in FIG.
Take in the T code 2H of the R code and output the DVD with the SYS 2 clock white signal. The decode counter counts up by the 5sys 2 clock,
Generates a compressed image request signal DRP1 and stores the compressed image memory 1
Read the next MFL code from 0-5 and invert the DVD output.

The next input MR code is 91H, which is an M code, so the l'sYs clock is counted 2176 clocks and the DI
'(, PL is generated. However, since the M code and T code are a pair, the DVD is not reversed at this point and the next T code is generated.
The p DVD is reversed by the count up of code 15H. In this way, the image is expanded during the period in which HAREA is at the H level, and the DA of the dither counter 10-10
The expanded image DVDO is written into the double buffer memory 10-15 by DR. Then, the count start value of the dither counter is set to B so that this DVD signal is read from the 8 addresses of HADR on the next line.
is set. However, the dither counter in FIG. 11 cannot perform binary expansion.l) The i ther signal is set to L level.

The comparators 14-4 and 14-5 are set so that the length of the HAREA signal during image expansion is the same as the H-ATtEA used when compressing the image of area B, and the number of locks is output. At the falling edge of the EA multiplication signal, the BOL detection circuit 10-7 determines whether the expansion operation of the current line is successful or unsuccessful.

The success of the decompression operation is determined by the fall of the HAR and EA double signals, the fact that the next MR code is EOL, and at that point the decode counter of the decompression circuit 10-6 counts up and generates the DH and PL double signals. We do what we are doing when all three conditions are present. This is because the code may contain an error when writing the MW code signal from the compression circuit to the compressed image memory 10-5 or when reading the MR code from the compressed image memory. If there is, an accurate interval signal HARE from the outside
DRPI which is the end of A and the end of the decompression operation of one code
The generation of the pulse and the line end code EOL tend to coincide. Here, it is determined that the above three conditions match and there is no decompression error, and the EOL detection circuit 10-7
generates DRP2 to read the MR code at the beginning of the next line for the next line.

The line-by-line operation when an expansion error occurs will be explained below with reference to FIG.

In FIG. 18, the line synchronization signal PBD inputted from the printer 10-3 causes the main-scanning address counter/decoder 10-12 to generate a main-scanning expansion period signal regardless of V-DEC. When the sub-scanning expansion section signal V-DEC from the controller 10-2 is at L level, BO
DECENB signal from L detection circuit and Buff CHG
The ENB signal is at H level, and the BuffCHG signal for switching the cedar pull buffer memory is always generated. Further, the Data ENB signal is at L level at this time and is fixed at L level by the image signal RMU-VDI'1 which is output to the printer by AND gates 10-28.

The controller 10-2 uses V-DEC to perform image expansion.
Set the signal to H level, then HAREA1, HAREA
, 2. . . . The line-by-line image expansion operation is performed in the order of HAREA 9. HAR when decompressing images
, the EA area is divided into three states. That is, the X state in which a normal decompression operation is performed, the y state in which a decompression error occurs, and the decompression error recovery state 2 in which DECENB from the EOL detection circuit is at L level.

The next line HARE where the V-DEC signal becomes H level
Image expansion is started in the expansion circuit 10-6 from AI. As shown in FIG. 18, if an expansion error occurs in the first HAREAL (state y), the EOL detection circuit 10-'
7 is Buff CHG ENB at the rear end of HAR, EAL
The signal and the DECENB signal are set to L level, and in the next line HAREA2, the double buffer memory is switched and the expansion operation of the expansion circuit 10-6 is stopped, and EOL detection processing for recovery from expansion errors is performed (state 2). .

The tOL detection circuit 10-7 outputs an EOL code F as an MR code for the section where HAREA is H as decompression error recovery.
The DRP2 signal is repeatedly generated until PH is detected. By detecting the EOL code, the synchronization relationship between the compressed image data and the HAREA signal is restored, and the first MR is used for image decompression in the next HAREA3.

The code is read, DECENB is returned to H level, and the decompression error recovery operation is completed.

When the image decompression operation is normally completed in the next HAREA3 (state of In response to the LNST signal input thereafter, Data BNB is set to H level.

HAREA4. Since the image expansion operation has completed normally on both lines of HAREA5, Buff CHG B
Although the NB signal remains at H level, an expansion error has occurred in HAR and EA6 as in HAREAI. Due to this state, the EOL detection circuit outputs the Buff CHG ENB signal to HA in HAR and EA6 so that the decompressed image data containing decompression errors written in the memo IJY of the double bass sofa memory will not be output to the printer.
It is set to L level at the rear end of REA6, and switching of the double buffer memory is prohibited until image decompression is successfully performed in HAREA8. However, in the section where the error is recovered in HAREA 7 and the section where the next decompression operation is performed in HAREA 8, the image data of the decompression effect decompressed in HAREA 5 is repeatedly output to the printer as an RMU-VD signal.

In this way, after the expansion error occurrence line and the error recovery line, the Buff CHG ENB signal causes the L
Since the Buff CHG signal due to NST is not generated, only the decompressed image data at the decompression success line (state of X) is RMU-V as shown in the RMU-VD signal in FIG.
It is output to the printer 10-3 as a D signal.

Furthermore, as mentioned above, the Data ENB signal is a signal that becomes H level for the first time after the successful extension line is generated.
This signal prevents decompressed image data containing errors from being output to the printer from the time the Vt-DEC signal becomes H level until the decompression success line occurs.

Furthermore, the DataBNB signal is configured to go to the L level one line after the V=DEC signal goes to the L level, so that the decompressed image at the last HAII (and BA9 line) is also correctly output to the printer. Ru.

Controller 1O-2Fi, expansion error counter 10
At -35, the LNST signals generated while the Buff CHG BNB signal is at L level are counted, and the total of lines where an expansion error has occurred and lines where error recovery has been performed are counted. In other words, this count value is
Indicates the number of lines for which decompression was not successful, and if the number of lines for which decompression was not successful exceeds 8 lines, the controller 10-2 immediately displays ■ as a decompression error misprint.
Processes such as setting the DEC signal to L level and stopping the decompression operation are performed. As a result, decompression errors are detected without waiting for one page of images to be decompressed, so that decompression errors can be quickly dealt with.

During expansion, the sub-scanning expansion section signal -DEC outputted by the controller 10-2 is output after counting the same number of lines in the line counter 10-11 as when outputting the V-ENC signal during compression.

Therefore, if no decompression error occurs during image decompression, the controller 10-2 controls the line counter 10-11.
Upon receiving the predetermined sub-scanning line count completion output from the VDE,
At the timing when the C signal is returned to the L level, the address output M-ADR from the memory address counter 10-8 becomes the same as the final M-ADR value when the decompressed image is compressed.

Comparators 10-14 include the final M-ADR during compression.
Since the value is set, controller 10-2 is VD.
The s MOVER signal should be detected when the EC signal is set to L level.

By the way, if a decompression error occurs during the decompression operation as described above, the KEOL detection circuit 1 is activated to recover the decompression error.
0-7 skips the MR code in order to increment the EoL code, so when the MOVER signal is generated, a count remains in the line counter 10-11. Even if you keep outputting the V-DEC signal in order to count all the remaining counts, the memory address counter 10-8 will stop because the MOVER signal has already stopped counting. The image data at the address of the count value at the time when the decompression operation is performed is not repeatedly taken into the decompression circuit 10-6, and all remaining lines become decompression error lines.

Therefore, in order to prevent this situation, controller 10-
2 sets the VDBC signal to H level and the line counter 1
While waiting for the count up from 0-11 s MO
Check the VER signal periodically, and if MOVER is detected when V-DEC is at Hv level, immediately set the V-DEC signal to L level to stop the image expansion operation and avoid counting extra expansion error lines. Make it.

In this way, when the memory address counter matches the maximum address at the time of image compression, the image decompression operation is stopped, thereby preventing unintended extra image signals from being sent to the printer 10.
It is also possible to prevent it from being recorded in 3.

Next, a case will be described in which a portion of the expanded image signal is trimmed and outputted to an arbitrary location on the output paper.

Figure 19 shows a point t with H1 bits in the main scanning direction and ■1 line in the subscanning direction from 81 points of an A4 size expanded image U.
This is an example in which an image T having a main scanning size of H2 bits and a sub-scanning size of ■2 bits is trimmed using 1 as a reference point and outputted on A4 copy paper without changing the positions of Vl and Hl.

As mentioned above, the expansion operation of one line is performed using the PB from the printer.
The operation is started using the LN-8T signal caused by the D signal as a synchronizing signal, and in FIG. 19, the expansion operation of one line starts when the HA D R from the main scanning address counter/decoder 10-12 is equal to 4677. . That is, H.A.
The comparator 14-4 is set to 4677 so that DR, is 4677 and H-AR,EA is at I] level. Also, when the expansion is finished at 4677 bits of A4 width, the comparator 14-5 is set to 0, and the H
Let the length of AREA be 4677 bits. I) AD writes the expanded image signal DVD expanded by the expansion circuit 10-6 to the double buffer memory IJ 10-15.
R, read HA D DC so that R performs the same operation
Comparator 1 that creates the timing of the 5TART signal
Set 4677 to 4-8 and dither counter 10-
The LD value of 10 counter 13-1.13-2 is also 4677
Set. As a result, the image signal compressed by U as described above is expanded as is.

As shown in FIG. 20, the controller 10-2 sends an A4 copy paper registration paper feed signal VSY to the printer 10-3.
At the same time as outputting NC, a sub-scanning expansion section signal V-DEC is outputted. As a result, the image expansion output starts at the same time as the printer feeds the paper.If there is no need to perform trimming here, by outputting V-DEC over the same time span as PvSYNc, you can output the expanded A4 image of U. All of these are output as is on A4 copy paper. Here, in order to perform the trimming as described above, the controller 10-2
In order to erase the image signal of the Vl line, the V-D
After outputting the EC signal, the TRM signal is fixed at the L level for one line, and the image signal read from the double buffer memory is fixed at the L level at 10-27. For this purpose, the comparator 14-6 that outputs the TRM signal that is counting the Vl line is set to IFFFH, and the comparator 14-7 is set to 4677 (1245H), and the flip-flop i4-12 is reset. Make sure it doesn't get too heavy.

Vl line count is line counter 10" -
After counting at 11, V during sub-scanning from the tl position.
2 lines, H2 bit T area is trimmed during main scanning. To that end, set the V2 line in the line counter 10-11, calculate the sub-scanning V2 line, and use the comparator to generate the TRM signal representing the H2 pit width from one point in the main-scanning trimming area between them. 14-6 is set to (4677-Hl), and comparator 14-7 is set to (4677-(H1+H2)). As a result, the TRM (V2.) shown in FIG. 19 is obtained.

Trimming of the T area between the tl point and the v2 line is realized by the constant set as described above.

When all the image signals in the T area are output to the printer,
The line counter 10-11 outputs a 2-line count end signal to the controller 10-2. At this point, the compressed image code of the shaded portion in FIG. 19 remains unread in the compressed image memory 10-5, but the image output of the desired T area has already been completed. The controller 10-2 needs to decompress the compressed image code in the shaded area, so it sets the VDEC signal to L level and stops the decompression operation. Since the VDEC signal has become L level, the data from the EOL detection circuit
The ENB signal is set to L level, and the subsequent vR line sends the image signal to the printer as a white signal (L level).
Region trimming output is completed. In this way, by not decompressing extra compressed image code, the number of decompression errors is reduced, which reduces the incidence of misprints caused by errors in the decompressed image, and improves copy operations. reliability is improved.

Next, the case where the image signal T trimmed as described above in FIG. 19 is moved to a position H3 pixels from the paper edge in the main scanning direction and output to the printer 10-3 will be described with reference to FIG.

In this case, when writing the expanded image into the double buffer memory, the expanded image is moved by one line, and when the moved image is read out from the double buffer memory, the desired T portion is trimmed. All movement and trimming of this expanded image is performed using HADR as a reference. That is, in FIG. 21(a), HA D R (4677-Hl)
The part of T expanded by the expansion circuit 10-6 in the address range from HADR (4678-(I-(1+H2)) is
is written to the double buffer memory by DADR, and in FIG. 21(b), the HA
DRK) When read, H3-H1 bits are moved and HADR.

(4677-H3) to HADR(4678,-(H2
It will be read in the range of 10H3)). This image movement is executed by DADR address control, and the second
When the T part of the decompressed image is written to the double buffer memory in Figure 1 (a) (when HADR is 4677-Hl)
4677-
All you have to do is write to the address of H3 using DADR. As is clear from FIG. 21(a), )rADI%=4
Set the DADR count start value in 677 to the main scanning movement bit number H3-H1.
And it is sufficient. This H3 takes a positive value when the image movement direction moves away from the main scanning reference point (I-(ADH=4677)), and takes a negative value when it approaches.

The image signal read out from the double buffer memory is T
The TRM signal is also trimmed by the RM signal, but as shown in FIG. 21(b), the HADR is changed from 4677-H3 to 4678-(H2+
N2), the comparator 14
-6 is set to 4677-H3, comparator 14
Set 4677- (H2+N2) to -7.

Next, a case in which the expanded image signal is moved in the sub-scanning direction (paper feeding direction) on the output paper will be explained with reference to FIG.

The part T in the expanded image U as shown in Fig. 22(a) is trimmed and output to an arbitrary position in the sub-scanning direction of the output paper. The movement of the image has been described above, so here we will discuss the timing of registration feeding of the copy paper and the timing of the start of expansion of the expanded image U in the sub-scanning direction.

In FIG. 22(b), the expanded image U is moved backward in the sub-scanning direction (paper feeding direction) of the copy paper and trimmed, and the tl point of the trimmed image is recorded at line V3 from the edge of the paper. This is an example.

The deviation in the sub-scanning direction between the copy paper and the expanded image U is V2
-V1 line, so the controller 10-2 is
After outputting the copy paper registration paper feed signal P-VSYNC to the printer 10-3, the line counter 10-
After counting V3-V1 lines in step 11, the sub-scanning expansion section signal VDEC is set to H level, and the expansion operation of the expanded image U is started. Here, to output the T-area image using the TRM signal, first set the V-DEC signal to H level, and then
This is when one line has passed. Then, when the line counter counts the 2 lines outside the sub-scanning of the T area, V-
The DEC signal is set to L level and the decompression operation is completed.

Figure 22 (C) is an example in which the expanded image U is expanded before registration feeding of copy paper, and point P of the trimmed image is output at line ■3 from the edge of the paper. V3 takes a positive value when it is on the copy paper, and a negative value when it goes outside the copy paper.

In FIG. 22(C), before outputting the registration paper feed signal PVSYNC to the printer, it is necessary to perform image expansion for three lines vl-■ in advance. Therefore, the controller 10-2 at the line counter 10=1 i,
After expanding the image for Vl-V3 lines, -VDE
Set the C signal to L level, interrupt the image expansion operation, and perform PVS.
Wait for the timing to output YNC. At the timing of outputting PVSYNC, the V-DEC signal is set to H level again to continue the interrupted image expansion operation, and -■3
The image is moved by a line.

Trimming of the T area is as described above, but if point P protrudes beyond the V3 line from the edge of the paper, the T area output on the copy paper will be trimmed accordingly. Before outputting the PVSYNC signal, the image is expanded for lines 1 to 3, and the DEC signal is returned to the L level. This is done in consideration of the case where RvSYNC from the reader is used as PvSYNC. There is. That is, when an image decompressed by the RMU and an image from the reader are overlaid and output to a printer, a common VSYNC signal must be used in order to accurately match the overlay position of the two images. However, VS from R, MU to leader
Since there is no way to notify YNC, PVSYNC is!
From J-Goo (7) VSYNC (RVSYNC) must be used. For the controller 10-2, which is asynchronous with the reader, it is difficult to determine the exact timing when RVSYNC is input. Therefore, the controller 10-2 receives the VSYNC (
Sufficiently before inputting RVSYNC, the MR and code of the decompressed image to be output on copy paper after decompression of the vl-v3 line image are cued from the compressed image memory, and decompressed again in accordance with RVSYNC. must be started. While waiting for RVSYNC, the decompression operation is interrupted by setting v-DEC to L level.

Note that when overlay operation is not performed, there is no need to synchronize reader C, and the output control of the PVSYNC signal is controlled by V.
-Line counter 10 as well as output control of DEC signal-
It can also be done with 11. Therefore, ■DECDEC-H
PVSYNC is immediately output without dropping to L level, and the decompression operation can be executed without interruption.

(4) Function of dithered image expansion If the compressed image by dither compression in (2) is simply expanded, the dither counter 10-1 at the time of dither compression
If the main scanning image is rearranged by 0 and expanded as it is, the copy output will be different from the original image. Therefore, in the dither image expansion process, the dither rearranged expanded image signal DVDO obtained from the expansion circuit 10-6 is processed in the same process as the binary expansion process in (3).
When writing to double buffer memory 1O-151C,
Reorder the dithered images from the original reader.

This rearrangement is realized by changing the order in which the write address counters DADR are generated when the double buffer memories 10-15 are expanded.

In other words, the images that have been rearranged as shown in 20-3 in Figure 16 are rearranged at 8-bit intervals so that they are in the order (16-2), but this is done using the dither counter shown in Figure 11. l) The i ther signal is set to H level, and the counters 13-1 and 13-2 are operated in the same way as in dither compression.

In this case, the counter load value set by the controller 10'-2 in the counter 13-1. The load value of the counter must be the same as the value used during dither compression. Otherwise, the arrangement of pixels within one block of the dither pattern of the image signal read out from the double backer memory will be out of order. Further, the comparator 13-3 is set to a value obtained by subtracting (N-1) from the load value of the counter 13-2 using the number N of blocks used during dither compression processing.

League/RM in the configuration of this system explained above
The detailed procedures of serial communication between the U and between the RMU and the printer and the image processing operation will be explained below. The programs shown in the flowcharts used in the following explanation are stored in advance in the memory ROM of the microcomputer that constitutes the control section of the league, printer, and RMU, and are controlled by reading the programs as appropriate.

The serial communication shown in Figure 6 is the DEVICE in Figure 8.
Connect+DEvIaEPOWERReady.

When all units including the RMU become capable of serial communication due to the Controller Power Ready signal, the league side unit sends a message to the printer side unit)
It is started by outputting an instruction (hereinafter referred to as a command) to (including the RMU). When the command reaches the printer, the printer outputs a response to the command (hereinafter referred to as status) to the league side units (including the RMU). Basically, if the RMU receives a command from the league, it outputs the same command to the printer, and if it receives a status from the printer, it outputs the same status to the league.

Serial communication between the league side unit and the printer side unit is performed by exchanging 8-bit commands and statuses, and at this time, one status is always returned in response to one command, and the status is returned before the command. Never.

FIG. 23 shows processing for RMU commands.

The RMU receives commands from the league. This command is the RMU mode instruction command 100-7 to 100-12 in Table 1, R, MU memory instruction command, RM
U) Rimming instruction 1 command, RM, U) Rimming instruction 2 command.

RMU) Rimming instruction 3 commands F, RMU) IJ rimming instruction 4 commands, RMU) Rimming instructions 5 commands F
, RMU) If any of the 6 rimming instruction commands (these 8 commands are collectively referred to as RMU instruction commands) is (S-100-1), check the metal body status in Section 10 below for 1 byte of each command. Return to league (S-100-5). If the input command is not one of the RMU instruction commands, the RMU determines whether the input command is a printer start command shown in Table 1 100-1 (described later) (S-100-2).

If the RMU is connected to the system, the printer start command is output from the league after the RMU instruction command described above is output from the league, so at this point, the RMU command described later is output.
, MU mode has already been determined. When this RMU mode is the "input mode" described later, the printer does not perform a copy operation, so this printer start command is not output to the printer, and the 10th league
Output the overall status of the table (S-100-3, S-
100-5). In addition, for commands that include information necessary for the operation of the RMU, such as the paper size instruction command, the contents of the command are memorized and then output to the printer (S-100-
4).

Next, processing for the RMU status will be explained using FIG. 24. When the printer manually inputs the commands output from the league through the R and MU, it outputs the status to the RMU for the commands input within a certain period of time.

When the RMU inputs the status from the printer, it determines which command this status corresponds to, and
Check whether the application status is in Table 15 for the application status request command in Table 108-7 (S-101'-1,)
. If the input status is an application status, after adding R and MU connection information (S-1'
012), output to the league as an application status.

Similarly, it is determined whether the status from the printer is the error occurrence unit status in Table 11 (
S-1'o1 aL If the compression failure flag described below is set, return the error unit status with compression failure information (RMU memory overflow) added, and if the compression failure flag is reset, return the error unit status to the league. The error unit status from the printer is returned to the league as is. It is also determined whether the status from the printer is the overall status in Table 10 or the misprint detailed status in Table 16 (S-101
-6, S-101-9), if the decompression error flag described below is set, add decompression error information to the overall status or misprint detailed status.S-1
01-8, S-1, 01-11), if the decompression error flag is reset, the overall status or misprint detailed status from the printer is returned to the league as is.

In response to command input from the league, the RMU transfers the command to the printer or returns the overall status to the league, and in response to status input from the printer, it transfers the status to the league or adds information to the status and processes it before forwarding it. Repeat what you do alternately.

In a system where R and MU are connected in this way, R
The MU communicates by capturing only necessary information and passing other information through.

This will shorten the time it takes to exchange information and allow the league to monitor communications, making it possible to simplify communication protocols.

The league and RMU shown in Figures 23 and 24 below.

This section provides a detailed explanation of the command statuses used for serial communication between printers.

Table 1 shows execution commands that prompt the RMU or printer to execute. When this execution command is output from the league, the RMU or printer returns the overall status shown in Table 10. 100-1 in Table 1 is a printer start command that requests the printer to start copying.

1'00-2 is a printer stop command that requests the printer to stop copying 1'OO-3, 100-4 is a paper feed instruction command that specifies the paper cassette 1'00-5 is a paper size that specifies the paper size This is an instruction command, and the second byte of this command (Table 2) contains bits 1 to 6.
A4. A3゜B4, B5, A4-R2B5
The paper size such as -R is encoded and stored. 100-
6 is the number of sheets instruction command, and the second byte of this command uses 6 bits from bit 1 to bit 6 to specify a maximum of 6 sheets.
You can set the number of copies per 4 sheets. 100-7 is RMU
The RMU mode instruction command, which is one of the instruction commands, stores RMU mode information in the second byte as shown in Table 5. 100-8 is an RMU memory instruction command that specifies the memory area of the RMU, and the contents of the specified memory area are stored in the second byte (Table 6), and only one bit of the corresponding memory area is set (“ 1”°). 1
00-9, 100-10, 100-11.

100-1'2.100-1'3,100-14 is RM
U) 2nd byte of rimming instruction command (Table 7).

The trimming amount can be expressed in millimeters from 0 mm to 512 mm in the third byte (Table 8).

Table 9 shows status request commands that request RMU or printer information. When the printer receives this command, it returns the statuses shown in Tables 10 to 16 to the league via the RMU. At this time, the RMU may add information about memory overflow or decompression error, which will be described later, and send it back to the league.

Tables 10 to 16 will be explained below. 1st
The 0 table is the overall status and mainly stores information about the general status of the printer and RMU. Bit 5 is set (``1'') if the printer is transporting paper. Similarly, bit 4 is set when there is a misprint, bit 3 is set when there is a wait, and bit 1 is set when there is an operator call error or serviceman call error. The error occurrence unit status in Table 11 stores information on which unit an error has occurred,
Operator call error status in Table 12, 13th
The service call error status in the table is information about the specific content of the error, and similarly, the cassette paper size status in Table 14 is A4. B5. Information on the paper size such as B4, application status in Table 15 stores information on what kind of unit is connected to the system, and misprint detailed status in Table 16 stores information on misprints.

By collecting these statuses, the league can learn the cause of errors in the overall system status, making system management easier.

Serial communication when the copy sequence is not being executed according to the command and status described above will be explained using chart 70 in FIG. 25.

The reader obtains RMU connection information from the application status in Table 15, which is output from the application status request command in 108-7 in Table 9 (S-10
2-1). In addition, the paper in the upper and lower cassettes of the printer is determined by the output of the lower cassette paper size request command in 108-5 in Table 9 and the upper cassette paper size request command in 1'08-6 in Table 9. Obtain size information (S-1, 02-2). After this, the overall status request command 108-1 in Table 9
Information on whether there is an error in the printer or RMU is obtained from the overall status in Table 10 and the error unit status in Table 11 by outputting the error unit status request command in 08-2 (S-102-3, S-
102-4). After this, it is checked whether there is an error (s-102-5). If there is an error at this time, Table 108-3 Operator call error status request command, Table 10
8-4 Output the service call error status request command and obtain detailed error information by inputting each status (S-102-6, S-102-7)
, necessary information such as paper fish can inform the operator that there is an RMU memory overflow.

If there is no error, it is checked whether the copy start key has been pressed (S-102-8), and if it has been pressed, serial communication is performed during copy execution (Table 116). If the copy start key is not pressed, the described operation is repeated until the copy key is pressed.

Serial communication during copy operation, operation of each unit, and signals will be explained using Table 17.

In the reader, RMU usage conditions (8-■) such as paper size selection (8-■), number of copies per copy setting (8-■), image reading mode (A-■), RMU mode, trimming data, and RMU memory instruction are set. When the operator inputs an input from the reader's operation panel and presses the copy key (8-■), the league sends an RMU instruction command (RM
U mote instruction command, RMU memory instruction command R,
MU) Rimming instruction command) (B-■) is output.

RMU is R, and when the MU instruction command is input, the selector 1 in FIG. Selector 2. Selector 3. Selector 4. Selector 5° Configure selectors such as video selector (C-
■). Following the RMU instruction command, the reader outputs a number of sheets instruction command (B-■), a top/bottom paper feed command (B-■), and a paper size instruction command (B-■). When the RMU inputs a paper size instruction command (C-■), the comparator shown in FIG.

Setting the dither counter, main scanning counter, etc. (C-■
). If the RMU mode is “memory input mode °°,” RM the printer start command to the printer.
Since U is not flowing, the printer does not output an output paper ready signal (hereinafter abbreviated as PREQ) to RMU, so R
The MU outputs PREQ to the reader instead of the printer (
B-■). When the RMU usage mode is not memory input mode, the printer start command reaches the printer, and the printer returns PREQ when it becomes ready to feed paper.
should be output to the RMU (D-■), and the RMU should output PR, E
Output Q to the reader (B-■). The leader is RM
When the PREQ of U (from the printer) is input, the output paper feed signal (hereinafter abbreviated as PRINT) is output from RMU.
Output to. (B-■).

When R, MU mode is "memory input mode", PRINT is not output to the printer (D-■) It is as if the printer inputs PRINT and outputs an image request signal (hereinafter referred to as VSREQ) in response. to RMU
outputs VSREQ to the reader (B-■)
. When the reader inputs VSREQ from RMU, it outputs ■5YNC (B-■) in order to output an image. The reader outputs the overall status request command and error unit request command at regular intervals during the copy operation.
It constantly checks for errors and RMU memory overflow (B-[phase]). Since the number of sheets is managed by the reader, when a printer stop command is input from the reader, the RMU will reset the mode (C-■
) and copying is completed.

The RMU is classified into four image input/output modes by RMU instruction commands from the reader 10-2.

The first is a mode called "memory pass mode", in which 'RMU outputs two image signals 1' (VDA and RVDB representing three values input from reader 10-1) to printer 10-3 as they are. The reader 10-1 and the printer 10-3 operate as if they were directly connected. Therefore, in this mode, the RMU outputs the signal input from the reader 10-1 through the video interface to the printer 10-3 as is. , the signals input from the printer 10-3 are output as they are to the reader 10-1.

The second mode is called "memory high speed mode", and the RMU receives the image signal RVD from the reader 10-1.
A is compressed and stored in a compressed image memory, and then the compressed image data is continuously read out and output to a printer.

That is, the reader 10-1 requires mechanical reciprocating motion.
Copying by scanning the original is only required once, and the second and subsequent copies do not require mechanical reciprocating movement, but the compressed image data stored in the compressed image memory of the RMU is repeatedly decompressed and output to the printer 10-3. This enables high-speed processing of large-volume copies.

The third mode is called "memory input mode", and the RM input mode is called "memory input mode".
U compresses the image signal input from the reader 10-1 and stores it in a compressed image memory.

The fourth mode is called "memory overlay mode," in which the RMU decompresses the compressed image data stored in the compressed image memory, combines it with the image signal input from the reader, and outputs it to the printer 10-2. do.

With this function, the original read by reader 10-1 and the RM
An overlaid copy of the image stored in U's memory is obtained.

“Memory high-speed mode” has three modes inside the RMU: “’retention mode,” “output mode,”
It is distinguished into ``Through Out Mode''. ``Retention Mode'' is ``Memory High Speed'' which compresses the image information (signal) from the original in the memory and passes it through to the printer. Retention mode°
Successful compression into memory by running .

Failure (RMU memory overflow) can be determined.

The reader successfully compressed the memory into memory due to the error unit request command during the copy operation.

If it is possible to obtain the information on FJ & IG (RMU memory overflow) and the compression to the memory is successful, image formation (copy) can be performed from the next copy (from the second copy onward) using the decompressed image from the memory. stops document scanning. The RMU resets the selector so that the memory can be expanded from the next copy. For example, the video selector 10-23 in FIG. 10 is reset to output the decompressed image from the RMU's memory to the printer.

The mode in which the selector is reset in this way is called "output mode 1." Conversely, if compression to memory fails, "retention mode will pass the image through while compressing it to memory." Therefore, it is necessary to perform an operation that does not compress the data into memory. This mode is called "through-out mode.""Through out mode" has the same selector settings in RMU as memory bus mode, but the image information from the league is a binary image with the same threshold generator A and H values in the former. On the other hand, the latter is a ternary image with VDA and VDB independent, so the name has been changed.
MU outputs a binary image at "memory high speed" regardless of the success or failure of image compression to memory, and
It becomes possible to eliminate the difference between the first image and the second and subsequent images. Table 18 shows the correspondence between RMU mode and RMU internal mode.

The league operation will be explained using the flowchart of FIG. 26.

First, when the copy key is pressed by the operator, the reader issues an RMU instruction command (S-
103-1), number of sheets instruction command (S-1'03-2)
, upper and lower paper feed command (S-103-3), 2 paper size instruction command (S-103-'4).

Outputs the printer start command (S-103-4), performs the initial settings necessary for the copy operation, and then the reader
After inputting PREQ from (S-103-10), P
Output R, IN, T to RMU (S-1'03
-1'O). Furthermore, start the timer (S-103
-11) Please wait for a certain period of time until this timer expires.
103-12), the optical system is not started when the RMU internal mode is "output mode" (S-103
-1'4), count down the number of sheets, and the number of sheets is 0.
(S-103-20), and if it is 0, output a printer stop command (S-1'0
3-21).

When the RMU internal mode is other than “Output Mode II, scan the optical system (S-103-1
5) Start reading the original (S-103-16)
Output the image to RMU. After checking the completion of reading (S-103-17), if it is in memory input mode, the number of sheets is not checked (reading of only one original is accepted). A printer stop command is output to the RMU (S-103-21).

“Memory input mode”, “output mode”
In other cases, count down the number of sheets and press (S-103
=19) When the number of sheets is 0, a printer stop command is output, and when it is not 0, the PREQ input is set to an input state and the above operation is repeated until the number of sheets reaches O.

The printer operation will be explained using chart 70 in FIG.

When the printer receives a printer start command (8-104-1) from the reader side (including MU), the printer starts various operations such as drum charging (S-104-2).

Once the printer is ready to feed paper (8-1'0
4-3), output PREQ to the league side (S-1
04-4), PR from the league side.

If PRIN'r is input corresponding to EQ (S-1
04-5) and paper feeding (8-105-6).

When paper is fed and images can be received (S-104-'7)
, VSREQ is output to the league (S-104-8).

The reader outputs VSYNC in response to VSREQ and outputs an image signal (S-104-9).

The printer performs copy processing (S-104-10).

Check if there are any errors, (S-1,'04-
11) If there is an error, the error is posted on the serial communication (s-1o4-12). If the above operation is repeated for one copy, the league will output a printer stop message, so check whether the printer stop message has been received.S-1'
04-13) Upon receiving this, the printer stops each part of the printer (S-104-14).

Before explaining the operation of the RMU, memory address management of the RMU will be explained using FIG. 28.

When storing compressed image information in the memory, the RMU can set arbitrary addresses on the memory as a compressed image write start address (hereinafter abbreviated as MS) and a maximum compressed image write address (hereinafter abbreviated as ME). RMU is MS and ME
Depending on the settings, it is possible to determine the success or failure of writing a compressed image to memory, and it is also possible to protect previously written image information.

Since the memory is limited, the maximum values are set as M T and M T . FIG. 28(1) shows a state in which no image is written to the RMU. At this time, MS←0
．． Set MB4-MLMT in advance. This also indicates the maximum free space available in memory. Fl,
When memory A is selected by the MU memory instruction command and A4 size copy is performed in dither memory high speed mode, R and MU are compressed in which mode of RMU is the image stored in memory A as shown in (2)? information on the size of the compressed image (MA-VIDEO), the original size of the compressed image (
MA-PSZ), league reading mode (MA-ME
THOD), memory A image write start address (MAS), memory A image write end address (
MAE). These pieces of information are written in the same way when writing to memory B and memory C is performed, and if no image has been written, it is assumed that information corresponding thereto has been written.

The state (3) is the state in which memory B and memory C are written in the state (2). Memo IJ in state (2)
When instructed to write to B or Memo IJC,
The area ■ in state (2), which is the maximum empty area, is MS←MAE
+i, set as MB4-MLMT. At this time, if memory A is specified again, the area including the upper and lower empty areas of memo IJA is set to a new MS←0, ME(-MLM'
l”. By setting like this (
This is the same as when memo IJ A is specified in state 1), and the memory can be used effectively.If memory A is specified in state (3), memo IJ A is specified in state (3).
J There is no continuous empty area in A, and the memory amount of memory A is compared with the memory amount of empty area ■ in state (3),
The one with the larger memory amount is set as the new memory A area. (3
), the empty area ■ is larger, so MS(
-MBE+1', ME←MLM'l'', and the old memory A area is set as an empty area.

The state (4) is the state in which image information has been written in the empty area (3) in the state (3). If there is a write instruction to memory B in this state, there is no continuous free space in the memory B area in state (4), and the memo IJ has the largest amount of memory among the B area, empty area ■, and empty area ■. The area is set as the new memory B area. At this time, if the empty area ■ has the largest amount of memory, MS, -0, ME, -
MC8-1 is set, and the old memo IJB area is set as an empty area. If the image is successfully written to the new memory B area after this setting, the state is (5), if the image writing fails, the state is (6), and if the compression to the memory fails, the state is (5). The written memory area becomes an empty area.

In states (5) and (6), memory A respectively.

Table 118 shows a comparison of memory amounts for determining MS and ME when memory B and memory C are specified.

In this way, the maximum number of empty areas generated is the same as the number of areas that can be specified by memory. MAS the amount of memory for this empty space
,MB8,MCS,MAE,.

Rational memory management can be performed by calculating from MBE and MCE. Even if MS.

MA-VIDEO even if writing an image to the new area set in ME fails (image compression error).

Images of the contents of MB-VIDEQ and MC-VIDEO
'? ? By setting N to no value and recognizing it as an empty area, rational memory management can be performed. In this example, the number of memory specified areas is 3゛°
However, it can also be realized by changing the number of memory designated areas 'N' depending on the amount of memory.

The "retention mode'1" of the RMU mode will be explained below as shown in FIG. 13, with reference to the flowchart in FIG.
, 140mmX from the point after 100mm in the sub-scanning direction
An example will be explained in which the image information B of 210 mm is trimmed and output. The RMU inputs Table 20 as the second byte of the RMU mode instruction command. bit 6,
Bit 5 is a bit to make the output density of the league image and RMU expanded image approximately 50%, and both are “
1'' is set and 104 in Table 5 is set as the RMU mode.
-2 like bit 4. Bit 3. Bit 2. Bit 1
is set. Memory A is specified as the memory instruction, and Table 21 is input as the R, MU memory instruction command. Tt, MU) Main scanning compression start position Hp (70mm) as trimming data of rimming instruction command 1
, RMU) Sub-scanning compression start position Vp (100 mm), RM as trimming data of rimming instruction command 2
U)! Hw (140mm), R, MU) during main scanning compression as trimming data for J Mig instruction command 3
The trimming data of the rimming instruction command 4 with Vw (210 mm) set during sub-scanning compression is output from the league in millimeter units (S-106-A-
1).

The controller 10-2 converts the above position information from the league into bit units/line units, and converts it into I(p=1102 bits, Vp=1574 lines, Hw==2204 bits, Vw=3307 lines as shown in FIG. 13). Obtain compressed image position/size information.

Depending on the designated RMU mode, selector 5 in FIG.
ELL (10-18), 5EL2 (10-19),
5EL3 (10-20), 8EL4 (10-21).

8EL5 (10-22), video selector (10-23)
) are -IL respectively R-VCLK, R-VDA, R, -VE
.

Select R-VB, P-BD, AO, and BO inputs.

In order to binary-compress the league image signal and store it in the compressed image memory, the dither signal shown in FIG. 11 is L-level varnished. R.M.U.
Since the mode is "memory high speed beat mode" (RMU internal mode is "retention mode"), the printer start command outputted by the league is received and passed directly to the printer (S-106-A-3). The RMU should input the PREQ signal indicating that the printer is ready to feed paper.S
-106-A-5), output this signal to the league (
S-106-A-6). At this point, the first frame of "Memory High Speed Mode" is being executed (S-, 1
06-A-7), input the paper size instruction command to specify the output paper size from the league S-106-A-8
), are stored and held in the MA-PSZ mentioned above. Based on the specified output paper size, settings for various counters described below are performed. First, set the MS (compressed image write start address) and ME (maximum compressed image write address) mentioned above using the memory address counter 10-8 and the comparator 1.
Performed on 0-14. The upper 10 bits 248H (584) of 1245H (4677) are set in the down counter 13-1 of the dither counter shown in FIG. 11, and the lower 3 bits 5H (5) are set in the down counter 13-2. Similarly, in the main scanning counter decoder shown in FIG. 12, 1245H (4677) is set in the down counter 14-1. Note that comparators 14-2 and 14-3 are used only during decompression, so no settings are made, and 14-4.1
The comparator 4-5 is D F 7 H which corresponds to Hp.
(3575) and Hp, Hw corresponds to 55 B
In order to set H (1371) and operate DADR at the same time as HADR, comparator 14-8 has 1245
Configure H (4677).

When the RMU inputs P, R, INT signals from the league (
8-106-A-10), output to printer (S-1
06-A-12). ■When the 5REQ signal is input from the printer (S-106-A-13), it is output to the league (
S-103-A-14).

At this point, the RMU mode is "memory high speed mode", but since it is the first memory, it branches to "RMU internal mode parity mode" (8-1.06-A-
18). And in Figure 30, VSY from the league
If you input NC ON (S-106-F-1),
and turn on VSYNC to the printer (S-106
-F-2), do. Figure 13 vp To generate 1574 lines, 626H (1
, 574), and when the line counter counts up (8-106-F-4), turn on the sub-scanning compression section signal V-ENC (S-106-F-5').
.

During sub-scanning of area B in FIG. 13, set the VW3307 to the line counter (S-106-F-6). According to the settings of the selector mentioned above, the compressed image code from the compression circuit 10-4 is written into the compressed image memo IJ 10-5 until the end of the 10-11 line counter while passing the image from the league through the printer (S-106 -F-7, S-1
06-F-8). At the end of image compression for a predetermined number of sub-scanning lines,
When the count-up of the line counter 10-11 is detected, which means the completion of the process, the V-ENC signal is turned off and the S-10
6-F-9), if the VSYNC off state from the league is input (S-106-F-10), VSYNC to the printer is turned off (S-106-F-11').

After this, in order to determine whether writing to the compressed image memory has succeeded or failed, move the image using the procedure shown in FIG.
Check the R signal S-106-C-1), MOVE
If the R signal is at H level, writing to the memory is determined to be a failure and the compression failure flag is set (S-106-C
-2) L. Information about compression failure (RMU memory overflow) can be conveyed to the league through serial communication during the aforementioned copy operation. Based on this information, the league determines that the retention operation using the compressed memory is at its last stage, and repeats the image output by scanning the original for the second and subsequent sheets, and ends the copying operation. With this function, even if the image signal from the league cannot fit into the compressed image memory, several copies of the film will be output from the printer. R.M.
At this time, U makes the memory area where the compressed image was being written an empty area, and with the compression failure flag, R
Change the MU internal mode to “through-out mode”.

"Through out mode" is the same as "memory pass mode", and the V-BNC signal is turned on (from L level to H level) and off (from H level to L level) in accordance with the league's VSYNC.
Since the RMU does not perform any compression operation, the selector and counter set the "retention mode", and when VSYNC from the league is input, it outputs VSYNC to the printer. Figure 33, S-106- D
-1, S-106-D-2), pass the image from the league directly to the printer S-106-D-3), V from the league
You can wait for SYNC. (S-106-D-4),
If VSYNC is input, VSYNC to print
When the league completes outputting image information for the set number of sheets, it outputs a printer stop command to stop the printer. The RMU ends the copy sequence by inputting this printer stop command (8-106-C-6).

On the other hand, if the MOVER signal is at the L level, the writing to the memory has been successful, so the league is notified of this via serial communication, the league stops scanning the second and subsequent documents, and compresses the RMU. A copy operation is performed using the decompressed image from the image memory. To output the decompressed image,
Selectors and counters must be reset,
Reset the “output mode” as shown below (
S-106-C-4, S-106-C-5). Fig. 10 8EL1', 5EL2.8EI, 3°5EL4.5EL
5. Video selectors are I-CLK and DVDO, respectively.
, P-BD, OVE.

H8YNC, A2. B2. It can be determined from the contents of MA-METHOD that the input of MA-METHOD is selected, and the compressed image data that has been subjected to binary image compression is stored in the compressed image memory. Therefore, in order to expand the compressed image data into a binary image, the Dither signal in FIG. 11 is set to L level.

The MA-PS mentioned above is used to set the counter and comparator.
The original size of the image information that is compressed and stored by extracting data from the memory areas specified by Z, MB-PSZ, and MC-'PSZ is 2204 in area B in Figure 13.
12F4H (4852), 14-2.
．． 14-4.14-5.14-6.14-7.14-8
1247H (4679),
2H (2).

1247H (4679), 9ABH (2475), dF
9I-((3577), 55dH(1373), 124
Set 7H (4679) and enter “output mode”.
sets the decompression error counter 10-35 to 0 in order to perform decompression from the compressed image memory. Set down counters 13-1 and 13-2 of the dither counter shown in FIG. 11 to LH (1) and 1BFH (447), respectively (
S-106-C-5).

The league uses the error unit status request command to recognize that there is no RMU memory overflow, and stops document scanning. The league is VSY
Since it does not output NC, RMU is VSYNC from the league.
VSYNC to the printer is turned on without waiting (S-106-D-1). In addition, the sub-scanning direction margin Vp1
In order to count 574 lines, the line counter is entered 7 times (S-106-D-2), and the line counter is up f, ruit-! (S-106-D-4), V
-Turn on the DEC signal and the number of sub-scanning lines for VW is 330
Set the 7th line to the line counter S-106-D
-5) Check image expansion and expansion errors until the line counter ends (8-106-B-22, S-106-
B-23). In this embodiment, if eight or more decompression errors occur, the decompression error flag is set and the copy operation is stopped. The RMU notifies the league through serial communication that the decompression error has occurred a predetermined number of times (eight times), and the league does not output paper feeding commands (PR, INT) after determining that the decompression error has occurred more than the predetermined number of times. Stop the copy operation. 11. In order for the MU to stop the expansion operation, first turn off the V-DEC signal (S-106-D-8), V
After setting the number of sub-scanning lines for R and incrementing the line counter, VSYNC to the printer is then turned off.

The league outputs a printer stop command to notify the printer that the copying operation has stopped, and the printer receives this command and stops the copying operation.

If the decompression error does not occur more than 8 times, the RMU repeats the decompression operation (set number of sheets - 1) times, and then stops with the printer stop command from the league (S
-1'06-C-6).

Next, the memory path mode will be explained using FIG. 33. As described above, the memory pass mode is a mode in which the two image signals RVDA and RVDB representing the three values from the league are directly transmitted to the printer without being stored in the compression memory.

That is, in the memory path mode, AI and Bl of the selector 10-23 in FIG. 10 are selected.

In addition, selector 10-18 is operated to select R, -VCLK from the league as osys, and selector 10-22 is operated to select P-BD from the printer as H8YNC (S-106-A- 2).

After this, the control signals coming from the league go to the printer.
Furthermore, control signals coming from the printer are output as they are to the league, and the RMU operates as if it did not exist. In other words, if VSYNC from the league is turned on (
8-106-Dl), turn on VSYNC to the printer, and further pass the image from the league through the selector 10-23 to the printer (S-106-D-2゜S-1
06-D-3). And V SYNC from the league
is turned off (s-i 06-D-4), VSYNC to the printer is turned off (s-106-D-5), and if a printer stop command has been input, the printing operation is stopped. On the other hand, if the printer stop command is not input, the same process is repeated for the set number of times.

Next, an example will be described in which an image written in the compressed image memory in the "memory input mode" is combined with an image from the reader in the "memory overlay mode" and output to the printer.

As a first step to perform a memory overlay operation, image information must be written to the memory. The RMU mode in which image information is written to this memory is the "memory input mode".
The instructions are 2 of the RMU mode instruction commands shown in Table 20.
<11'tMU) lJ trimming instruction based on the 2nd byte of the RMU memory instruction command shown in Table 21, and the trimming area specification data from the operator's operation section of the reader as shown in Table 24. 1 command to R
Input the contents of the trimming data of the MU trimming instruction 6 command from the reader. 'Memory input mode 1
In this case, the printer start command 100-2 in Table 1 does not need to be output to the printer, and the printer does not perform a copy operation.
, 5EL2.5EL3.5EL4.

5EL5, select the video selector respectively
, -CLK, R-VDA, R-VE, R-VE, H8Y
N.C.

Set AO and BO (S-106-A-2). Also, since the printer does not perform a copy operation, it does not output the PREQ signal to the RMU, but the R,MU outputs the PREQ signal to the reader instead of the printer (8=106-A-
4, S-106-A-6). By serial communication from the reader.

When the paper size instruction command is received, the memo IJC
is specified, the paper size is stored in MC-PSZ (paper size of memory C) in the memory of the control unit of II and MU, and the image information stored in MC-METHOD (memo IJ C area) is stored. The fact that the image is a binary image is also stored in the read mode (reading mode).

Paper size and trimming data entered from the reader HP (
main scanning reference position), Vp (sub-scanning reference position), H
w (during main scanning), Vw (during sub-scanning)', HM
(main scanning movement position) and VM (sub-scanning movement position),
The down counter (14-1) has 4677, the comparator (14-4) has 3575 from HP, and the comparator 1 (
1'4"-5), 1371 from Hw, comparator (
14-8) is 4677 from the paper size, and the dither counter (
14-1') is set to 4677. The memory address counter (10-8) includes the aforementioned MS (compressed image writing start address), comparator L, -ta (10-1'4).
ME (compressed image maximum write address) is set in (S-106-A-9).

Even if RM'U receives a PRINT signal from the reader (
S-106-A-10), the printer does not perform a copy operation, so it does not output to the printer, and instead of the printer, V
Outputs the SREQ signal to the reader (S-106-A-1
'l', S-1'06-A-1"4'). When you input vSYNC on from the reader (8-106-B-1
), Vp up to area B in Figure 17 (157 in this example)
4) Line counter (
Set Vp to 1'0-11) (8-1o 6-
B-2). Detecting that the line counter has counted up ('8-106-B-a), turn on the V-ENC signal to start the compression operation (S-106-B-4
). Also, during sub-scanning to compress Vw (in this example, 33
07) on the line counter (S-i 06
-B-5). Then, the compression operation is repeated in the compressed image memory until the line counter counts up (S-1
06-B-6, S-106-B-7). To detect that the line counter has counted up and stop the compression operation, turn off the V-ENC signal (S-106-B-
8). After that, to detect that the VSYNC signal from the league has turned off (S-106-B-9), and to check whether there is a memory over (the memory address counter has exceeded the maximum address for writing compressed images). ,
Detects the MOVER signal (Fig. 31, S-106,
-C-1).

If the MOVER signal is at H level, it means that writing to the memory has failed, and a compression failure flag is set to notify the league of the compression failure (S-106-
C-2). Due to this, information about RMU compression failure is added to the error unit status mentioned above, and the league
Recognize MU compression failure. Also, in case of compression failure, M
C-PSZ (paper size of memory C), MC-METOD
(reading mode), MC8 (memory C start address), MCE (memory C end address), MC-VIDE
The same settings are made for the O (compression mode) information as if nothing had been written in memory C. This allows the specified memory area when compression fails to be recognized as an empty area and to be effectively used for the next compression operation. On the other hand, when compression is successful,
MC8, MCE, MC-METHOD.

Stores information necessary for MC-VIDEO and MC-PSZ. These are used when decompressing from the memory C area.

If a printer stop command is input from the league (S-106-C-6), the RMU ends the sequence processing.

Now, with the input mode mentioned above, for example memo! JB
Assume that image information of KAJ size is compressed and stored.

Then, consider decompressing this image information in "memory overlay mode", combining it with the image information from the league, and outputting it to the printer. “′O”
By doing so, the output is output to the printer at approximately 50% density. In addition, the decompressed image is converted into Hp bits in the main scanning direction.
RMU mode instruction for trimming an image area of main scanning size Hw bits and sub-scanning size Vw bits using the VP bit point as a reference point in the sub-scanning direction and outputting it to A4 size.

The second byte of the command is the one in Table 25, and the RMU
Assuming that the data in Table 26 is used as the second byte of the memory instruction command, and that the trimming data 1 to 6 of the RMU trimming instruction command 1 to RMU) trimming instruction command 6 are converted into bits or lines, Hp and Vp, respectively. , Hw, Vw, HM, V
A value M is set and output from the league to the RMU. The RMU is selected by selector 1 in Figure 10. Selector 2. Selector 3. Selector 4. Selector 5° Video selector selection R-VCLK.

DVDO, LN-8T, R-VB, P-BD.

A3 and B3 are selected, and the Dither signal is set to L level.

Now, in FIG. 34, the sub-scanning movement direction of the expanded image T is determined (S-106-G-1). As a result, if the moving direction of T is the same as the sub-scanning direction, the process proceeds to FIG. 35.

Then, if you input the paper size instruction command from the league, it will be stored separately from the paper size of the compressed image.
The processing for the PREQ signal, PRINT signal, and VSREQ signal is the same as in the "memory pass mode 0°" or the "through-out mode, and will therefore be omitted. H that converted the memorized paper size and trimming data to bits and lines
Counters are set as follows using P, Vp, Hw, Vw, HM, and VM. 4677 for converter 14-4, 01 for comparator 14-5, 4677 for comparator 14-8, down counter 13-1.1
4677- (Hp -MM) to the counter 14-2, 4677 to the counter 14-1 When the moving direction of the image is the same as the sub-scanning direction, at the same time as inputting VSYNC ON from the league (S-106-H-1 ), turn on the VSYNC to the printer (s-106-H-2), set the line counter to make the V-DEC signal to H level by (VM-Vp) lines later than the VSYNC that outputs the V-DEC signal to the printer. (S-106-H-3). After the line counter is up (S-106-H-4), the comparator 14-6
IFFFH is set to IFFFH, and 4677 is set to comparator 14-7.

4677.4G77-(
HM-Hp) S-106-H-5), V-
Turn on the DEC signal (S-106-H-6).

Setting TRM signal for trimming (S-106-
H-7) After setting the counter for L and VP lines and counting up (,5-tO6-H-8,8-10
6-H-9), set the TMR signal so that image expansion is performed S-1'06-H-10), set the Vw line to the line counter S-1'06-H-11), I
After compositing the J-da image and the expanded image, and performing the compositing operation for the Vw line (S-106->H-12), turn off the V-DEC signal to stop the expansion operation (
S-106-H-1'4).

Next, in order to trim the T area, comparators that generate TRM signals are set, and as shown in Figure 25, comparator 14-6 is set to 4677-HM, and comparator 14-7 is set to 4677-, (HW+HM) (S-106-I-10).

As a result, the T area is outputted onto the copy paper from the location t in FIG. 22(C).

Next, the controller 10-2 controls Vw during sub-scanning of the T area.
8-106-I-11'), detects that the image signal of the T area is output to the printer, and turns off the VDEC signal to stop the expansion operation (8-106-I-11'). S-106-I-12).

Now that the controller 10-2 has finished decompressing and outputting the compressed image data, it waits for all images of the reader 10-1 to be output to the printer 10-3 (S-106-I-1
3). When it is detected that the PVSYNC of the reader is turned off, the VSYNC to the printer 10-3 (PVSYNC
) to end the output of one image to the printer 10-3 (S-106-I-14), and in order to check whether the set number of copies has been completed, the process shown in FIG. Proceed to S-106-C-6).

On the other hand, if the sub-scanning movement direction of the decompressed image T is the opposite direction to the sub-scanning direction, the process advances from (S-106-G-1) in Fig. 34 to Fig. 36, and the compressed image in Fig. 22 (C) Sub-scanning image position V1=VP from A4 size image signal expanded from compressed image data from memory.

When trimming the area T in the sub-scanning image where V2 = -VW and moving it to a location where the distance from the starting edge of the sub-scanning paper to tl is V3 = VM, and combining the image signals from the reader and outputting it to the printer. corresponds to the controller 10-
2 or less control operations are executed as shown in FIG.

Main scanning image position H of T area, = Hp, main scanning image width H2
= Hw and the distance from the starting edge of the main scanning paper to tl by moving the T area in the main scanning direction is Hs "" HM,
According to FIG. 21, the load value of the counter 14-1 (HADR) is 4677°.
Set. The comparator 14-8 that starts the dither counter is set to 4677, and the dither counter 1 is set to 4677.
Set 4677- (HM-Hp) in 3-1.13-2 (S-106-I-1). Here) O8YS
Set SEL 1 (10-18) to set it as ICLK, set the start address of the compressed image data of U in the memory address counter 10-8, and set V-
Turn on the DB(:' signal and start expanding the 0 image. Here, the line counter i o-i 1 determines the line length (VP-V
M) Count the lines (s-106-I-3), -carry V
-Turn off the DEC signal and interrupt the expansion operation (8-
106-I-4).

Image decompression from this point on is performed using the reader 10-1's VSYNC (P
08YS is RV due to 5EC1 (10-18) because it is performed using the clock of reader 10-1 in synchronization with VSYNC).
Select CK. This can prevent pixels from being misaligned in the main scanning direction when the reader image and the 0 image are combined.

In this state, when VSYNC is detected from the reader, the controller 10-2 sends the registration paper feed signal PVS to the printer.
In addition to outputting YNC (S-106-I-6), set T to not output the expanded image during the VM line in sub-scanning.
Set the RM signal to L level.

This is achieved by setting IFFF'H in the comparator 14-6 and 4677 in the comparator 14-7 (S-106-I-7). After this, in order to start the interrupted image expansion, the memory address counter 1 is
Leave the values 0-8 as they are, and turn on the ■-DEC signal.
Make it. Here, the line counter 10-11 counts the VM lines until 7 images are output (S-106-I
-9).

In this way, the RMU operates according to the four mode specifications described above.

(19) In this embodiment, run-length encoding is used as the compression method, but other encoding methods such as MH and MR may be used.

Furthermore, it goes without saying that the number of times an abnormality in expansion occurs, which is used to determine whether to stop the expansion operation or output, is not limited to eight. Further, the compressed image signal may be one transmitted over a telephone line or the like.

As explained above, according to the present invention, even if there is an abnormality in the decompression operation of a compressed image signal, a normal image signal is output instead, thereby preventing image distortion, and even if the abnormality occurs repeatedly. In such cases, the extension operation or output should be stopped to prevent unnecessary extension operations and to take prompt measures against abnormal recovery.Table 2Table 3Table 4Table 5Table 6Table 7Table 7 Table 8 Table 9 Table 1O Table 11 Table 12 Table 13 Table 14 Table 15 Table 16 Table 18 Table 19 Table 20 Table 21 Table 22 Table 23 Table 24 Table 25 Table 26

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a configuration example of an image processing system to which the present invention is applied, FIG. 2 is a diagram explaining image reading operation by league, FIG. 3 is a block diagram showing a schematic circuit configuration of league, and FIG. 5 is a block diagram showing the schematic circuit configuration of the printer, FIG. 6 is a diagram showing the contents of the video interface, FIG. 7 is a diagram showing the image signal transmission method, and FIG. 8 is a diagram showing the schematic configuration of the printer. The figure shows various signals of the video interface. Figure 9 is an explanatory diagram of the encoding operation.
FIG. 0 is a block diagram showing the detailed configuration of the RMU, FIG. 11 is a configuration diagram of a dither counter, FIG. 12 is a configuration diagram of a main scanning counter decoder, FIG. 13 is a diagram showing a trimming state of an original image, and FIG. 15 is a timing chart showing the image signal compression operation, FIG. 15 is a diagram showing the storage state of the memory, FIG. 16 is an explanatory diagram of dither compression, and FIG. 17 is a timing chart showing the image signal expansion operation, FIG. 18 is a timing chart showing the operation during a temporary elongation error. Fig. 19 is a diagram showing the trimming operation related to the main scanning direction and the image movement operation related to the main scanning direction, and Fig. 22 (a)
, (b), and (C) are diagrams showing image movement operations in the sub-scanning direction, FIG. 23 is a flowchart diagram showing the procedure for serial communication of commands, and FIG. 24 is a flowchart diagram showing the procedure for serial communication of statuses. , FIG. 25 is a flowchart showing the communication procedure before the copy operation, and FIG.
Figure 27 is a flowchart showing the operation of the league, Figure 27 is a flowchart showing the operation of the printer, Figure 28 is a diagram showing the state of the memory area, and Figures 29 to 36 are RMU.
1-1 is a league, 1-2 is an RMU, 1-3 is a printer, 1O-2 is a controller, 10-4 is a compression circuit, 1O-5 is a compressed image memory, 10 -6 is an expansion circuit, to-15 is a double buffer memory, 10-23 is a video selector, 10-8
is a memory address counter.

Claims (1)

[Scope of Claims] Input means for inputting a compressed image; decompression means for decompressing and outputting the compressed image input from the input means; means for detecting an abnormality in the decompression operation in the decompression means; If the means detects an abnormality in the expansion operation of the expansion means, the means outputs a previously expanded decompressed image signal with no abnormality in place of the decompressed image with the abnormality, and counts the number of occurrences of the abnormality in the decompression operation. An image processing system comprising means for: stopping the decompression operation of the decompression means or the output operation of the decompressed image when the count value of the count means exceeds a predetermined number.