JPS61176262A - Picture processing system - Google Patents

Abstract

PURPOSE:To form an accurately an image by supplying the picture signals given from an output CONSTITUTION:In case the picture signal R-VDA given from a reader has a sudden change and.

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 in binary code 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 with a storage capacity of at least the same number of bytes is required, and to store multiple images, of course, a capacity that is twice that number is required. .

Therefore, it is conceivable to compress the image when storing the image. According to this, the amount of data for a typical image is 1/1
It is possible to reduce the number of images to about 0, and it is possible to store images for a plurality of images with a relatively small capacity memory.

However, the amount of information after compression depends on the image content and is uncertain. Therefore, there may be cases where not all images can be stored in the currently storable area, and in this case, it becomes impossible to output complete image information from the storage means.

The present invention has been made in view of the above points, and it is an object of the present invention to make it possible to reliably perform an image forming operation even if a compressed image signal cannot be stored in a storage means. means for compressing the image signal from the output means; storage means capable of storing a plurality of image signals compressed by the compression means; If there is no area in the storage means to store the image signal compressed by the compression means, the image signal from the output means is sent to the formation means without passing through the storage means. The present invention provides an image processing system that supplies images.

Hereinafter, the present invention will be explained in detail using the drawings.

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) 1-2, and an image forming device (hereinafter referred to as printer). It consists of 1-3.

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

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, reading one line by the CCD 3-1 is main scanning reading 2-2, and movement of the main scanning line in a direction substantially perpendicular to the main scanning direction is sub-scanning 2-3.

Figure 3 shows a simple structure and diagram of the reader.
A CCD licensor 3-1 converts reflected light obtained from one original by an illumination system (not shown) into a bit-serial image electrical signal for one main scanning line. CCD3
The analog image electrical signal corresponding to the intensity of reflected light from the original document 1 is digitized by the A/D converter 3-2 into a multi-bit digital image signal for each pixel. The digitized snow image signal is sent to a binarized comparator 3-
3.3-4g is compared with the binarized threshold signals generated from the threshold generators 3-5 and 3-6, respectively, and output as two systems of 1 or 0 binary-valued image signals VDA and VDB. Ru.

Assuming that the analog image signal input to the A/D converter 3-2 is converted into a 6-pit digital image signal, 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
When 0, HVDA=O, VDB=O1 The output from A/D converter 3-2 is 21 to 41 OjlJ Goha V D
A=0, VDB=1, A/D:
If the output from ry meter 3-2 is 42 to 63, V
DA=1. V, DB=1 and fx, from IjK draft (
The Dm image signal has three states VDA= depending on its reflection density.
O, VDB=O1 VDA=O, VDB=1, vDA=1
．． It is represented by vDB=1. Finally, 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.

Further, the threshold comparators 3-5, 3-6 can also generate a dither matrix threshold using a conventionally known systematic dither method, and by this, it is also possible to express halftones with fiVDA and VDB ternary image signals. It is possible.

RMU1-2 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 laser light emitted from a laser driver 4-2 in the axial direction of the photosensitive drum 4-1, and 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. Development unit that develops images with toner)
, 4-5 is a print paper cassette, 4-6 is a print paper pickup roller that pulls out print paper sheets one by one from the print paper cassette 4-5, and 4-7 is a print paper pickup roller that picks up print paper sheets 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); Reference numeral 4-10 denotes 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 the required portion of the charge applied to the photosensitive drum 5-2 is removed using a laser beam, and a developing process is performed using a developer to print the image. This is done by transferring and fixing onto 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-e 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. VSYNC, which is a section signal, video input signal (VE), which is a one-line section signal, and image clock CLK.
A synchronization signal consisting of

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 0, the recorded image VB is ternary-synthesized 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 (DPRDY) indicating that the control unit of each device is operating normally, a signal (PR, EQ) indicating that the image receiving device is ready for output paper feeding, and an output paper feeding from the image output device. A signal (PRINT) and an image request signal (5REQ) from the image receiving device are transmitted. Also,
The control signals include information on the paper size of the paper feed stage of the printer, 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 image encoding in R and MU 1-2 will be explained based on the above.

The image signal from the reader is bit-serial image information, so the image information read at a resolution of 400 dpi (400 dots per inch) is 3 on an A31 page.
．． The memory capacity is 7MB. This is equivalent to 574 pieces of image information in a 64-bit DRAM, and in terms of implementation,
Since it is unrealistic in terms of cost, 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 1 of the image signal.
The result of counting the number of consecutive ``'' states or ``0'' states using a counter is treated as an image signal.
FIG. 9 shows the format of run-length encoding in this embodiment.

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 bits 6 to bitQ.

Furthermore, in the 7-bit binary format, the run length (consecutive number of 110) can only be expressed from 0 pit 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 2'' bytes is a make-up code (hereinafter referred to as M code) that represents a run length that is an integral multiple of 128 bits, and the remaining 1 byte is a termination code (hereinafter referred to as T code) that represents a fraction from O bit to 127 bits. (written as code) Totoru.

In order to distinguish between the makeup code and the termination code, as shown in (9-1) (bit 7 is used as an identification flag, 1 indicates the M code and 0 indicates the T code). An example will be explained in which the image signal of 4677 bits of one line corresponding to the main scanning length of 297 mm of an A3 size original is composed of a black and white pattern consisting of 5 consecutive bits of white signal and 4672 consecutive bits of black signal.

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 black bits are 128 degrees or more, so they are composed of an M code and a T code.
As for the code, 64 is expressed in binary code as (9-5). In other words, it is encoded as M code (128 x 36) + T code (64) - 4672. As explained above, The image signal of one line of 4677 bits mentioned above is (9-3), (9-4), (9-5).
It is expressed in 3 bytes.

In addition, as a signal to separate one line, EOL:r-do (End of Line near) shown in (9-2) is used.
) is used. Since bit 7 of this EOL code is 1, it looks like an M code, but in the M code, 1) i
If bit □ is all 1 from t 6, 1' 6
This means a series of 2'56-bit image signals. In this example, the maximum data length of one line is 467
It is 7 bits, and in M code, bit 6 is always O, so normal run-length encoding does not generate M code where all bits are 1, and EOL code and M code are clearly defined. distinguished.

Add the EOL 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 1/14'6 of the original signal. Note that this encoding method requires that data indicating whether the image is white or black be included in the code. instead,
■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. Also, the number of consecutive images is exactly 128.
Even if it is an integer multiple of , and can be encoded using only the M code, a T code 0 representing white 0 is added because 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 10-1.
The leader of 10 becomes the leader of 1-1 in Figure 1.
-3 printer to 1-3 printer, 10-4 compression circuit to 1-2-1, 10-5 compressed image memory to 1-
The expansion circuits 2-2 and 10-6 correspond to 1-2-3, respectively. 10-2 is a controller, which is composed of a microprocessor and peripheral I10 port devices, 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 internal states of R and MU.

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.

10-5 is a compressed image memory in which the run length code generated by the compression circuit 10-4 is written.

It also supplies the read code to the decompression circuit 10-6.

The decompression circuit 10-6 is a circuit that decompresses the run-length code from the compressed image memo IJ 10-5 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. Still, the EOL detection circuit is a circuit that operates only when the sub-scanning and expansion period signal V-DEC from the controller 10-2 is asserted, and 1, 1: EOL detection is performed when the signal ■・DEC is negated. The buffer change enable (Buff) which is the output signal of the circuit 10-7
CHG ENB ) signal and data enable (Data
BNB ) signal is fixed at high (H) L/bevel, D
The R and P2 signals are 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 the controller 10-2 can set a write/read start address, and furthermore, the counter output can be read by the controller 10-2. The count clock for this counter 10-8 is a compression circuit 10-4, an expansion circuit 10-6, and an E
The DWP signal, DRP1 signal, and DRP2 signal 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. In this embodiment, the dither counter consists 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 that generates section signals H-AR and EA for compression and expansion for each line, and a start signal DC8TART for the dither counter 10-10.
, generates an address (HADR) to the double buffer memory 10-15, and generates a signal (T
RM) 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, respectively, which generate an A=B output when the value of the counter 14-1 is equal to the value respectively set by the controller. 14-10 to 14-12 is 14 with flip-flop
Set by the output of comparators from -2 to 14-7,
will be reset.

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 signal MOVERVc, which is the A≦B output of 0-14, is output from the memory address counter 10-2.
It is detected that 8 has reached the 8 force value of 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 is NOR, gate 1
0-30 inhibited by memory address counter 10-
The count-up operation of 8 is stopped.

Reference numeral 10-15 is a double buffer memory consisting of memories for one line each of memory X and memory Y, and the read and write operations of the memories X and Y are opposite to each other. This buffer switching is performed by inputting the BuffCHG signal, and the read address signal and write address signal are input from the dither counter 10-10 to 0DAD.
R and HAD from main scanning counter decoder 10-12
I use R 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 from 10- and 22, it is used as the main scanning synchronization signal H8YNC inside the RMU and the BD double signal R-BD to the reader.

10-18 is a φsYs clock selector, which selects the video clock B-VCLK from the reader and I-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 backup memory 10-15, which selects the image signals R, -VDA from the reader and the expanded image signal D from the expansion circuit 10-6.
VDO is selected according to instructions from controller-10-2.

10-20 is a selector for the LN-8T signal used as a count start signal for the main scanning counter 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, -VB double signal controller 10-2
Select based on instructions from.

10-21 is a selector for the output line (VB multiplied signal -VB), which selects the OVE signal corresponding to the VE from the main scanning counter decoder and the VE multiplied signal from the reader, -VE according to instructions from the controller 10-2. select.

10-22 is the H8YNC selector as mentioned above,
The selection is made based on instructions from the controller 10-2.

10-23 is an image signal P- output to the printer 10-3.
■Controller 10-2 with DA and P-VDH selectors
controlled by AO of video selector 10-23,
The image signal R-VDA from the BO large input beam is connected, and by selecting these AO and BO large inputs, the image signals P-VDA, P
-V D B c7) R-VDA from the leader on both
As is clear from FIG. 7, the recorded image VD output to the printer becomes a binary image. , the image signal R-vDA from the reader is output as the image signal P-VDA going to the printer;
-VDBllj:, image signal R of the leaders, -VDB
further AND game) The signal passed through 10-34 is output.

The other input signal R- of this AND game) 10-34
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 is combined into an image.

If the R, -HALF signals are in a logic state of 0 (hereinafter referred to as +tL level), the image signal P-VDB goes to the printer.
is fixed at L 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 DA signal is recorded on the output paper. This means that when the R-HALF signal is at the L level, the lighting time of the laser beam emitted from the laser unit 5-4 is approximately half that of when it is at the H level, and the R,-HALF signal is at the L level. Approximately 50% of the image signal from the reader is
% output image density is obtained.

When A2 manual power and B2 manual power are selected by the video selector 10-23, the image signal P-VDA going to the printer is output from the double buffer memory 10-15 by AND gate 1.
(The signal RMU-VD passes through 1-27 and 10-28. Also, the image signal P-VDB going to the printer is the signal RM
It becomes a signal obtained by further passing U-VD through AND gates 10-32. The other input RMU-HALF' of which AND gate 10-23 is a signal from the controller 10-2, and if this RMU-HALF signal is at H level, the image signal P-VDB going to the printer is connected to P-VDA. The recorded image VD that becomes the same signal and is output to the printer is the seventh
As can be seen from the figure, a binary image is created by the image signal RMU-VD. 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, P-vDA has double buffer memory 10
The image signal RMU-VD from -15 is transmitted, but P
-VDB is at L level tt, so the image signal VD output to the printer is 1 pixel (
The image signal is recorded on the output paper as an image signal with a duty of about 50% for one video clock section. This is RMU-
When the HALF signal is at L level, it means that the ON time of the laser beam emitted from the laser unit 5-4 is approximately half that of when it is at H level, and R, MU, -H
By setting the ALF signal to L level, an output image density of about 50% 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 go to the printer by the action of the OR gates 10-31°10 and -32.
is the image signal R-VDA, R-V from the reader
D B (!: Tough' Luhatsu 7 Amori 10-1
It is a composite of five image signals RMU-VI). Here, the image signal VD output to the printer by combining the above-mentioned R-HA becomes as shown in Table 1.

10-25 is a Buff from the EOL detection circuit 10-7
CH() END signal (double buffer switching permission)
Accordingly, a three-person power A N gates the 9LN-8T signal to generate a switching signal BuffCHG for the read buffer and sheet buffer of the double buffer memory 10715.
This is the D gate.

10-35 is an expansion error counter that counts the number of lines in which the expansion circuit 10-6 has an expansion error.

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

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

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

(3) (Binary decompression) A function of reading out the binary compressed image stored in the compressed image memory 10-5, subjecting it to binary decompression processing, and outputting it to the printer 10-3.

(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 VB double signal synchronization signal representing one main scanning line as shown in FIG. Then, the sub-scanning section for one page is represented by the V8YNC 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, we will extract the image information A of 400 dots/1 nch (400 dpi) of the decomposed dust from the A3 size (main scan 297 mm (corresponding to 4677 bits), sub scan 420 mm) transmitted from the reader as shown in Figure 13. 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 lQQ 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
11(, 10-18SEL1 is set to select the clock R-VCLK from the reader 10-1 as the clock ('jsys) used inside the MU.

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

Next, the synchronization signal LN-8T for each line is set, but this is done by setting 1O-20SEL3 to use the R-■E times signal from the reader 10-1. As mentioned in the explanation of the video interface, an R-BD double signal is required as a synchronization signal to generate 10-1 fdR, -VE. 10-22SEL5 is set to output the IBD signal from the signal generator 10-17.

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

Comparator 1 sets the main scanning direction of area B in Figure 13.
Perform on 4-4.14-5. That is, the H-AREA signal from the flip-flop 14-11, which is set and reset by the outputs of these two comparators, is sent to the compression circuit 10-
4, and the compression circuit 10-4 performs run-length encoding processing on the image data during the main scanning period where this signal is at H level, and writes it into the compressed image memo I710-5.

Therefore, the comparator 14-4 is set to a value 3575, which is obtained by subtracting 1102 bits corresponding to the main scanning direction margin of 7Qmm up to the area B in FIG. 13 from 4677. In addition, the comparator 14-5 has 14Qmm during main scanning of area B.
The value 1371 is set by further subtracting 2204 pits corresponding to minutes from 3575.

The dither counters 10-1 and 0 start to operate due to the output DC8TART from the comparator 14-8.
14-1 down counter and dither counter 10-10
In order to operate simultaneously, the comparator 14-8 has four
Set 677.

The following constants are set for the dither counter 10-10. That is, a count start value of 4677 is set in the counters 13-1 and 13-2, and p is set in order to perform binary compression.
Set the ifhe 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 DADR.

HADR, both R-VB times signal rise 467
We will be counting down from 7.

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

Expansion circuit 10-6. Since the expansion start signal V-D E Cij given to the BOL detection circuit 10-7 is at the L level, the DRPI signal doubler P2 signal is at the L level, and the BOL detection circuit 10-7 is at the L level.
uff CHG ENB signal and DataENB signal are at H level.Expansion circuit 10-6°EOL detection circuit 10
-7 is configured so as not to affect the compression operation.

Furthermore, there is a compressed image memo on memory address counter 1o-8! Set the write start address to J10-5.

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 'lQQmm 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 111-11 goes down by the LN-8T signal, that is, when the main scanning section signal R-VE from the reader is 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-ENC 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-VB multiplied signal of 3307 lines for the B area is input from the reader, the line counter 10-11 counts up again, and the controller 10-2 detects this and converts the V-ENC signal to H level/L/ to L level,
The image data compression operation of the compression circuit 10-4 is stopped.

In this way, the image signals R and -VDA that are continuously input from the reader 10-1 are input in the main scanning direction at any section where H-AREA emitted from the main scanning counter decoder 10-12 is at H level, and in the sub-scanning direction. In the scanning direction, the V-BNC generated by the controller 10-2 is trimmed to an arbitrary section of H level, encoded by the compression circuit 10-4, and written to the compressed image memo IJIO-5. Shown below. R, -V in Figure 14
DA is an example of inputting an image signal of one line.
This shows the case where 2204 bits for black and 5 bits for white are input. By this R-VDA input, the compression circuit 1
A 5-byte run length code is generated at 0-4. In other words, the first white 2 produces a 2H T code, then the black 2204 produces an M code 91H, and a T code 15H2.
The last white 5 creates a 5H T code, and then GH-ARE.
An EOL code is generated due to the end of A, and the compression circuit 10
The data is written into the compressed image memory 10-5 by the write request DWP pulse from -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 signals R, -VDA from the reader change rapidly and a large amount of compressed code MW code is generated, the pressure -
A situation arises in which all compressed codes MW codes cannot be written in the image memory 10-5. Furthermore, when writing multiple pages of compressed image data to the compressed image memory 10-5 as shown in FIG. 15, the previously written compressed image data T
A situation arises in which a part of the data is damaged by the newly written compressed image data U. 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, a compressed image s (end address SE) and a compressed image T (start address TS) are stored in the compressed image memory.
) is stored, address SE and address TS
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.
, and the start address TS of the compressed image T is set in the comparator 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 DWP is generated at the gate 10-30. is gated, the memory address counter is stopped, and further write operations are prohibited. In this way, the compressed image T is protected. In addition, the controller 10-2 receives the A from the comparator 10-1.4.
≦ 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, and the memory area where the image data was completely written is set as an empty area and the image is stored. Output from memory 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 rapidly, and the main scanning as used in this embodiment Image compression methods that encode image continuity in a direction have difficulty in effectively compressing 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 embodiment, an 8x8 dither (IJ) is used for each block, the details of which are shown in block (16-2) in Figure a. If the image signal read from the reader is uniformly at 32 levels, a black signal will be output where the IJ threshold value is 32 or higher.
An image as schematically shown in (16-1) is obtained using the dither matrix (16-2).

(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)
The signal becomes a VDA signal, and state changes occur eight times in four blocks. The number of state changes is proportional to the number of blocks, and for an A4 sheet with a width of 297 mm, 1168 state changes occur, so by run-length encoding,! 1l11
The amount of encoded data is 170 bytes. This one
The 170 bytes is about twice the amount of data of the original image, which is 4677 bits, and the amount of image information increases.

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 it in the order of the blocks, (16 As shown in EVDO -4), the state changes twice. In other words, as shown in (16-3), since the signals based on the same threshold value for each block have a little variation in the black or white state, it is possible to increase the continuity of the image by arranging them consecutively. become.

In this embodiment, the rearrangement of the image signals according to the dithering (IJ) is performed by controlling the readout of the double buffer memory 10-15 using a dither counter 10-10.

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 10-10 counts down to 8-bit intervals when reading image data from the double buffer memory 1f)-15.

This 8-bit interval reading is removed by the l)i ther signal from controller 10-2 shown in FIG. In addition, the controller 10-2 is (16
-1) According to the number N of main scanning compressed blocks, 13-2
A value obtained by subtracting N-1 from the counter setting value is set in the comparator 13-3. This number of compressed blocks N indicates the main scanning compressed data length given to the compression circuit 10-4.
-A RE Corresponds to the length of the A signal (H-AR
EA signal bit length)=Nx8.

l) In Fig. 11, when the ither signal reaches the 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 sets it 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 dither compression of an image signal having an arbitrary length in the main scanning direction can be supported.

(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 the trimming and movement processes are not performed, and the compressed image signal from area B in FIG. 13 is converted into a compressed image memo IJ 10- For example, let us assume that the compressed image is stored in area B of A3 size output paper 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. In other words, in FIG. 4, the printer is constructed so that the distance from the transfer position of the photosensitive drum to the laser-exposed point a-4 is equal to the distance from b to the registration paper feeding point C. Therefore, the A3 output paper is sent out using the registration roller 4-7, and after the sub-scanning paper is fed by 100 mm, the expansion operation is started, and the three images shown in FIG. 13 are output. Therefore, after outputting the registration paper feed signal VSYNC to the printer, the controller 10-2 outputs the registration paper feed signal VSYNC to the line counter 10.
-11 is set to the number of lines corresponding to lQQmm.

This value is 1574 lines at a resolution of 400 dpi.

The line synchronization signal LN-8T during image expansion is 10-20 8Bj3. ．． 10. =j2. ．． BDC signal -BD from the printer is selected by No. 2 8EL5. Further, the internal clock yIsys is generated by the internal clock generator 10 in synchronization with H8YNC selected by 5EL5 of 10-22.
-16 I-CLK generated at 10-18 5EL1
Select with .

Now, with the line counter 10-11 mentioned above, the sub-scanning margin is 1.
When the controller finishes counting 1574 lines equivalent to 0.00 mm, the controller outputs the image expansion signal V-DEC and starts the expansion operation of the B area. The address value is set to the comparator 10-14, and the final MADR value at the time of compression is set.

The decompression circuit 10-6 decompresses the image line by line according to the VDB'C signal from the controller 10-2, and the decompressed image signal DVDO is sent to the double buffer memory 10-2.
15 and output to the printer one line later. At this time, the dither counter 10-101d 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 HADR value is A, the down counter 14-1 of the main scanning colorant decoder 10-11 has a value corresponding to the left margin amount described above. A0LMG considering the value LMG (17'3 bits)
.

A is set in the comparator 14-2. A-4676 for comparator 14-3, A for comparator 14-4, 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 the dither counters 13-1' and 13-2 start operating when the 2203° counter 14-1 reaches A'. 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] -
HA D R of 0-1,2 counts down from A + L M G, counts the clock L M G,
When T-TADR reaches AK1, an OVB signal, HAR, and EA multiplied signal DC8TART signal are generated.

This L M G is the number of clocks corresponding to the main scanning length from the BD sensor of the printer to the image effective portion of the photosensitive drum, and the image signal output to the printer while the OVE signal is at H level is printed on the output paper be done.

After HA D R reaches A, when HA D R reaches 75 KB by counting 1102 clocks corresponding to the margin of 7'Qmm to area B in Fig. 13, the TRM signal goes to H level and data is transferred from the double buffer memory. The output image signal of HA is enabled by game) 10-27, and
When D R reaches B-22,03, 2204 pixels corresponding to 140 mm during main scanning of area B are output to the printer, and the TRM signal goes to L level.The image signals going to the printer after that are output to the printer. )10-27. The decompressed image signal stored in the double buffer memory in this way is output to the printer, and writing of the decompressed image DVD to the double buffer memory 10-15 is as follows.

At the same time as OVE rises, the H-A REA signal applied to the expansion circuit 10-6°EOL detection circuit 10-7 goes high.
level, and the decompression circuit 10-6 starts decompressing the compressed image MR and the code.

The expansion circuit 10-6 reads the compressed image MR code from the section compressed image memo IJ 10-5 in which the sub-scanning expansion section signal V-DEC and the main-scanning expansion section signal H-AREA are at H level, and takes the code into a decoding counter (not shown). %
It counts down by the I'SYS clock and generates an expanded image DVD. That is, as shown in FIG. 17, M'll.

It takes in the T code 2H of the code and outputs the DVD with the osYs 2-clock white signal. The decode counter counts up by the 5sys2 clock, generates a compressed image request signal DRP1, and stores the compressed image memory 1.
Read the next MR code from 0-5 and invert the DVD output.

Since the next input MR code is 91H, which is an M code, 2176 clocks of the sy's clock are counted to generate the DRPI. However, since the M code and T code are a pair, the DVD is not inverted at this point, but is inverted by the count up of the next T code 15H. In this way, the image is expanded during the period in which HAREA is at H level, and the dither counter 10-10 (DAI)
The decompressed image DVDO is written to the double buffer memory IJIO-15 by R. Then, the count start value of the dither counter is set to B so that this DVD'0 signal is read out from 8 addresses of HADR in the next line. Also, the dither counter in Fig. 11 is 2
The Dither signal is set to L level for value expansion.

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-AREA signal used when compressing the image in area B, and the number of locks is output. When the HAREA signal falls, the EOL detection circuit 10-7 detects the success or failure of the extension operation of the current line.
Judgment will be made.

The success of the decompression operation is determined by the falling edge of the HAREA signal, the fact that the next MFL code is BOL, and at that point the decode counter of the decompression circuit 10-6 counts up and the DRPI signal is generated. This is done when three conditions are met. This is because there is a possibility that an error may be included in the code when writing the MW code signal from the compression circuit to the compressed image memo U10-5 or when reading the Mlt code from the compressed image memory, and the MR code may contain an error. Accurate section signal HA from the outside if there is
D, which is the end of R, EA and the end of the decompression operation of one code.
The generation of the RPI pulse does not match the line end code EOL. Now, the above three conditions match,
EOL detection circuit 1 determines that there is no decompression error.
0-7 generates DR, P2 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, a main scanning expansion period signal is generated by the main scanning address counter/decoder 10-12 in response to the line synchronization signal PBD inputted from the printer 1o-3, regardless of V-DEC. EO when the sub-scanning expansion section signal V-DEC from the controller 10-2 is at L level.
DECENB signal from L detection circuit and BuffCHGE
The NB signal is at H level, and the Buff CHG signal for switching the double buffer memory is always generated. ]) ata ENB signal is at L level at this time, and the image signal RMU-VD output to the printer is AND game)1
0-28 is fixed at the seat level.

The controller 910-2 is a V-DEC controller for image decompression.
Set the signal to H level, and then HAREA■, HAREA
2; . . . HAREA 9 The image expansion operation is performed line by line in this order. HAR when decompressing images
The EA area is divided into three states. That is, the X state performs a normal decompression operation, the y state where a decompression error occurs, and the decompression error recovery state 2 in which DBCENB from the BOL detection circuit is at L level.

The next line H''AR where the V-DEC signal became H level
Image expansion is started in the expansion circuit 10-6 from the EAI. As shown in FIG. 18, if an expansion error occurs in the first HAREAI (state y), the EOL detection circuit 10-
7 sets the Buff CHG ENB signal and DECENB signal to L level at the rear end of HAREAL, and then the next line H
In AREA2, the switching of the double buffer memory and the decompression operation of the decompression circuit 10-6 are stopped, and BOL detection processing for decompression error recovery is performed (state 2).

The EOL detection circuit 10-7 repeatedly generates the DRP2 signal until it detects the EOL code F'FH as an MR code in the section where H and l't'EA are H as decompression error recovery. By detecting the BOL code, the synchronization between the compressed image data and the HAREA signal is restored, and the first M of the next image decompression block in HAREA3 is restored.
The R 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 Data ENB is set to H level by the LNST signal inputted thereafter.

Since the image expansion operation has completed normally on the two lines HAREA4', MAR, and EA5, Buff CHG
Although the ENB signal remains at H level, HARFiA
6, a decompression error occurs as in HAREAL. In this state, the fi BOL detection circuit
, the Buff CHG ENB signal is set to H to prevent the decompressed image data containing decompression errors written to memory Y of the double bath sofa memory from being output to the printer.
AR, EA set to L level at the rear end of 6, then HAfEA
In step 8, double buffer memory switching is prohibited at the point where image decompression is successful. 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 sent to the printer by RMU--
It is output as a VD signal.

In this way, the Buff CHG BNB signal causes the LN after the expansion error occurrence line and the error recovery line.
Since the 13uff CHG signal by ST is not generated, only the decompressed image data on the decompression success line (state of X) is RMTJ as shown in the R and MU-VD signals in Fig.
-It is output to the printer 10-3 as a VD signal.

Furthermore, as mentioned above, the Data END 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 when the V-DEC signal becomes H level until the decompression success line occurs.

Furthermore, the DataENB signal is configured to go to the L level one line after the V-DEC signal goes to the L level, and the expanded image in the last 9 lines of HAREA is also normally output to the printer.

The controller 10-2 has an expansion error counter 10-2.
At step 35, the LNST signals generated while the Buff CHG ENB signal is at L level are counted, and the total number of lines in which an expansion error has occurred and lines in which error recovery has been performed is counted. In other words, this count value represents the number of lines that have been successfully extended, and
0-2: If the number of lines for which decompression was not successful exceeds 8 lines, the VD will be immediately notified as a decompression error misprint.
Perform processing such as setting the ECDEC signal to a bell and stopping the expansion operation. As a result, decompression errors are detected without waiting for one page of images to be decompressed, so that decompression errors can be quickly processed.

During expansion, the sub-scanning expansion section signal V-DEC outputted by the controller 10-2 is output by 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.
VDBC upon receiving the predetermined sub-scanning line count completion output from
At the timing of returning to the DEC signal bell, 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 was compressed.

The comparators 10-14 include the final M-A D at the time of compression.
Since the R value is set, the controller 10-2 should detect the % MOVER signal when the VDECDEC signal is set to bell.

By the way, when an expansion error occurs as described above during the expansion operation, the EOL detection circuit 10-7 skips the MR code in order to invert the BOL code due to the expansion error error, so a MOVER signal is generated. At times, line counters 0-11 have a count remaining.

Even if you keep outputting the 7-DEC signal in order to count all that remains, the memory address counters 0-8 have already stopped counting due to the MOVER signal, so the memory address counters 0-8 will stop. The image data at the address of the count value at the point in time is repeatedly fetched into the decompression circuit 10-6, and all remaining lines become decompression error lines.

Therefore, in order to prevent this situation, the controller 10'
-214, % while waiting for count up from line counter 0-11 with vDECDEC signal bell
Check the MOVER signal periodically, and if MOVER is detected when V-DEC is at H level, immediately set the V-DEC signal to L level to stop the image expansion operation and avoid unnecessary expansion error line Ω counting. Do it like this.

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 transmitted to the printer 1o.
3 can also be prevented from being recorded.

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 of H1 bit in the main scanning direction and ■1 line in the sub-scanning direction from point S1 of an expanded image U of A4 size.
This is an example in which an image T having a main scanning size of H2 bits and a sub-scanning size of V2 bits is trimmed using □ as a reference point, and outputted on 84 copy paper without changing the positions of ■□ and H.

As mentioned above, the expansion operation of one line is performed using the PB from the printer.
It is started using the LN-8T signal by the D signal as a synchronizing signal, but in Fig. 19, the expansion operation of one line starts when the HA D R from the main scanning address counter decoder 10-12 becomes 4677. . That is, H.A.
, 4677 is set in the comparator 14-4 so that when DR is 4677, H-AR and EA are at H level.

Please make sure to finish decompression at A4 width 4677 bits.
Comparator 14-5171J: Set O, HA
Let the length of REA be 4677 bits. In addition, DC5TART is used to write the expanded image signal DVD expanded by the expansion circuit 1 (1-6 into the double buffer memory jO-15) so that the DADJ reading HADR performs the same operation.
4677 is set in the comparator 14-8 that creates the timing of outputting the signal, and 4677 is also set in the LD value of the counter 13-1.13-2 of the dither counter 10-10. 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, sub-scanning expansion section signal V-I), EC
to focus on. . With this, the image expansion output starts at the same time as the printer feeds the paper, so if you need to trim at this point, use the lever V-DBC4-PV8. By outputting over the same time span as YNC, the entire A4 expanded image of U is output as is on A4 copy paper. Therefore, in order to perform the above-mentioned trimming, the controller 10-2 fixes the TRM signal at the L level during the V1 line after outputting the -DEC signal to erase the image signal of the 1st line. Then read the image signal from the double buffer memory and set it to L level at 10-27.
Fixed to. For this reason, the comparator 14-6 that outputs the TR and M signals that are counting the Vl line has i,
F F FH, 4677 (
1245H), the flip-flops 14-12 are only reset.

``After counting the V1 line with the line counters 10-11, trimming of the T area with a sub-scanning width of 2 lines and a main-scanning width of H2 bits is performed from the position t□.For this purpose, the line counters 10-11 The comparator 14-6 calculates the sub-scanning v2 line and generates the TRM signal representing the H2 bit width from the t point of the main-scanning trimming area between them.
(4677-Hi) and comparator 14-
7 is set to (4677-(Hs,+,H2)). As a result, TRM (v2) in Figure 19 is obtained.

By setting the constants as described above, trimming of the T area between the point tl and the line 2 is realized.

When all the image signals in the T area are output to the printer,
Line counter 1.0-11 to controller 10-2
Then, a count end signal on the V2 line is output. At this point, the compressed image code of the shaded portion in FIG. 19 remains in the compressed image memory 10-5 without being read out, but since the image output of the desired T area has already been completed, The controller 10-2 does not need to decompress the compressed image code in the shaded area, and sets the VDEC signal to the L level here to stop the decompression operation. Since the VDEC signal became L level, the data from the EOL detection circuit
The E'NB signal goes to L level, and the image signal to the printer for the following ■R line becomes a white signal (L level).

The trimming output of the T area is completed. In this way, by not decompressing the extra compressed image code,
The amount of decompression errors that occur is reduced, thereby reducing the incidence of misprints caused by errors included in decompressed images, and improving the reliability of copying operations.

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 with HAT)R as a reference. That is,
In FIG. 21(a), HA D R (4677-Hl
) to HADR (4678-(H, 10H2)), the part of T expanded by the expansion circuit 10-6 is D.
ADR writes to the double buffer memory and the second
In Figure 1 (b), HAD
When read by
78-(J10H3)). This image movement is executed by the address control of DADR, and when the portion T of the decompressed image is written to the double buffer memory in FIG. 21(a) (HADR is 4677-
The pixel generated at the time of Hl) may be written to the address of 4677-H3, which is moved by H3-Hl, using DADR. That is, as is clear from FIG. 21(a), HAD
The DADR count start value at R=4677 is 4677-(H3
-H engineering). This H3 takes a positive value when the image movement direction moves away from the main scanning reference point (1-TADR=4677), and takes a negative value when it approaches.

The image signal read out from the double buffer memory is T
Although this '14M signal is trimmed by the RM signal, as shown in FIG. 21(b), the HADR is changed from 4677-H3 to 4678-(H2
Comparator 1 so that the H level is between +H3)
Set 4677-H3 to 4-6 and comparator 1.
Set 4677- (H2+H3) to 4-7.

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 ■3 from the edge of the paper. This is an example.

The misalignment between the copy paper and the expanded image U in the sub-scanning direction is ■2
-V1 line, so controller 10-. 2 outputs the copy paper registration paper feed signal P-■5YNC to the printer 10-3, and then outputs the line counter 10.
After counting V3.--1 line at -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, the image in the T area is output using the TR and M signals when one line (■) has further elapsed after the (2) to DEC signals were set to the H level. Then, when the line counter counts the V2 line outside the sub-scanning of the T area, the V-DEC signal is set to L level, and the expansion operation is completed.

FIG. 22(C) is an example in which the expanded image U is expanded before register feeding the copy paper, and point P of the trimmed image is output at line V3 from the edge of the paper, and 11 points are on the copy paper. v3 takes a positive value if it is above the copy paper, and a negative value if it goes outside the copy paper.

In FIG. 22(C), it is necessary to perform image expansion for lines 1-V3 in advance before outputting the registration paper feed signal PVSYNC to the printer. Therefore, the controller 10-2 uses the line counter 10-11 to
, -73247 minutes of image decompression, -VDBC
The signal is set to L level, the image expansion operation is interrupted, and the PVSY
Wait for the timing to output NC. At the timing of outputting PVSYNC, the V-DEC signal is set to H level again, the interrupted image expansion operation is continued, and the image is moved by three lines of V and -V.

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 not be trimmed by that amount. Before outputting the PVSYNC signal, the image of the V and -V3 lines is expanded and the -V-DEC signal is returned to the L level, but (7) RVSYNC from the reader as PVSYNC
We are considering the case where . That is, when an image expanded by R, MU and an image from a 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, from RMU to leader V
Since there is no way to signal SYNC, PVSYNC
The VSYNC (RVSYNC) of Rietaka et al. must be m-. Reader and asynchronous controller 10
-2, it is difficult to determine the detailed timing of when VSYNC is input. Controller 10-2 then receives VSYNC (RV) from the reader.
Sufficiently before inputting the SYNC), the MR and code of the expanded image to be output on the copy paper after the expansion of the Vl-■3 line image are located at the beginning of the compressed image memory.
The decompression operation must be started again in time with RVSYNC. That is, while waiting for RvSYNc, V
-DEC is set to L level to interrupt the decompression operation.

Note that when overlay operation is not performed, there is no need to synchronize the breaker C (the output control of the PVSYNC signal is
-Line counter 10 as well as output control of DEC signal-
It can also be done with 11. Therefore, without once lowering the VDEC signal to the L level, PVSYNC is immediately output, 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 the images into the double buffer memory 10-15, the images are rearranged in the order of 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 to 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. ])i ther signal is set to H level, and the counters 13-1 and 13-2 are operated in the same way as in the case of 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 value 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 buffer 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 the dither compression processing.

In the configuration of this system explained above, the league, RM
Detailed procedures for serial communication between U and between R, MU, and printer, and image processing operations will be described 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 unit of the league, printer, and RMU, and are read out as appropriate to perform control operations. .

The serial communication shown in Figure 6 is DEVIOE in Figure 8.
Connect+DgvxcEPOWERReady.

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 corresponds to 1.0' O-7 to 10100-12 in Table 1 below.
0R mode instruction command, RMU memory instruction command,
RMU) Rimming instruction 1 command, RMU) Rimming instruction 2 command.

RMU) Rimming instruction 3 commands, RMU) Rimming instructions 4 commands, RMU) Rimming instructions 5 commands)'
, RMU) If it is any of the 6 rimming commands (these 8 commands are collectively referred to as RMU commands) (S-100-1), each command 1 bye) The status is sent back to the league (S-100-5). If the input command is not one of the RMU instruction commands, the RMU determines whether it is a printer start command as shown in Table 1 100-1, which will be described later (S-100-2).

If an 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.
The MU mode has already been determined. If this RMU mode is the "input mode" described later, the printer does not perform a copy operation, so the RMU does not output this printer start command to the printer and outputs the overall status shown in Table 10 to the league (S-100 -3, S-100
-5). For commands that still contain information necessary for the operation of the RMU, such as a paper size instruction command, the contents of the command are stored and then output to the printer (S-100-4).

Next, processing for the RMU status will be explained using FIG. 24. The printer is 11. When the MU inputs a command output from the reader, the status of the command input within a certain period of time is output to the RMU.

When the RMU inputs the status from the printer, it determines which command this status corresponds to, and
It is checked whether the application status in Table 15 corresponds to the application status request command in Table 108-7 (S=101-1). If the input status is an application status, after adding RMU connection information (S-101-2
), output to the reader as application status.

Similarly, it is determined whether the status from the printer is the error occurrence unit status in Table 11 (
S-101-3), if the compression failure flag described below is set, return the error unit death status with compression failure information (RMU memory overflow) to the league, and if the compression failure flag is reset. In this case, 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-101-11), 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.

Provides a detailed explanation of the commands or statuses used for serial communication between printers.

Table 1 shows execution commands that prompt R, MU, or the 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.

100-2 is a printer stop command that requests the printer to stop copying operation) '100-3, 100-4 is a paper feed instruction command that specifies a paper feed cassette 100-5 is a paper size instruction command that specifies paper and size , the second byte of this command (Table 2) contains bits 1 to 6.
A4. A3゜B4, B5, A4-R9B5
The paper size such as -R is coded and stored. 100-
Reference numeral 6 is a number of copies instruction command, and in the second byte of this command, six bits from bit 1 to bit 6 can be used to set the number of copies of up to 64 copies. 100-7 is R,
The RMU mode instruction command, which is one of the MU instruction commands, stores RMU mode information in the second byte as shown in Table 5. 10゛〇-8 is the RMU memory instruction command that specifies the RMU memory area, and the second byte (sixth
Stores the contents of the memory area specified in the table), and stores the contents of the memory area specified in
Only the bits in these memory areas are set (“111”): 1oo-c+, too-to, too-tt.

100-12, 100-13, 100-14 are RMU
) 2nd byte of rimming instruction command (Table 7).

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

Table 9 shows commands for requesting status of R, MU 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.

Below, Tables 10 to 16 will be explained in order. 1st
The 0 table is the overall status and mainly stores information about the general status of the printer, R, and MU. 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 during wait, and bit 1 is set when there is an operator fool error or a serviceman call error. The error occurrence unit status in Table 11 stores information on which unit an error has occurred, and the operator call error status in Table 12 and the service call error status in Table 13 contain information on the specific content of the error. The cassette paper V is status in Table 14 is A.
4. 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 the flowchart of FIG. 25.

The league obtains R, M'U connection information from the application status in Table 15, which is output from the application status request command 108-7 in Table 9 (S-
1'02-1). In addition, the paper in the upper and lower cassettes of the printer is determined by the cassette paper size status in Table 14 based on the output of the lower cassette paper size request command in 1.08-5 in Table 9 and the upper cassette paper size request command in 108-6 in Table 9. Obtain size information (S-102-2). After this, there is an error in the printer JMU according to the overall status in Table 10 based on the output of the overall status request command in 108-1 in Table 9 and the error generated unit status in Table 11, and the error generated unit status in Table 11. Obtain information about what (S-102-3, S
-102-4). After this, it is checked whether there is an error (S-102-5). 108-38 to obtain more detailed information if there is an error at this time.
．． tPerator call error status request command, 1
108-4 Table service call error status request command is output, and detailed error information is obtained from each status input (5-1o 2-6, s-t
02-7), it is possible to notify the operator of necessary information such as out of paper, R, MU memory overflow.

If there is no error, it is checked whether the copy start key has been pressed (S-1, 02-8), 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 reader issues an RMU instruction command (RM
U mode instruction command, R, MU memory instruction command R
, MU) rimming instruction command) (B-■) is output. When the RMU inputs the RMU instruction command, the RMU 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 two paper size instruction commands (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 0", the RMU sends a printer start command to the printer.
Since the printer is not flowing, the printer does not output the output paper enable signal (hereinafter abbreviated as PR, EQ) to the RMU.
, MU outputs PRBQ to the reader instead of the printer (B-■). When the R, MU usage mode is not memory input mode, the printer start command reaches the printer and the printer outputs PR when it is ready to feed paper.
Output EQ to RMU (D-〇), R, MU are P
Output R and EQ to the reader (B-■). When the reader inputs PRBQ (from the printer) from R and MU, it outputs a corresponding output paper feed signal (hereinafter abbreviated as PRINT).
is output to the RMU. (B-■).

When the R, MU mode is "Memory input mode 1", 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 VSRBQ) in response. to R,M
U outputs VSR and EQ to the reader (B-
■). When the reader inputs VSRBQ from RMU, it outputs VSYNC (B-■) to output an image.

The reader issues an overall status request command during the copy operation,
It outputs an error unit request command at regular intervals and constantly checks for errors, RMU memory overflow, etc. (B-[phase]). The number of sheets is managed by the reader, so when a printer stop command is input from the reader, R and MU reset the mode (
C-■) and the 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 R, MU input two image signals R, VDA and R, VDB representing three values input from the reader 10-1 to the printer 10-3 as they are. Output, reader 10-1 and printer 1
It operates as if 0-3 were directly connected. Therefore, in this mode, the RMU outputs signals input from the reader 10-1 through the video interface to the printer 10-3 as they are, and outputs signals input from the printer 10-3 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.
+p Copying by scanning the original is only required once, and subsequent copies are made by RMU without mechanical reciprocating movement.
Since the compressed image data stored in the compressed image memory of the printer 10-3 is repeatedly expanded and outputted to the printer 10-3, high-speed processing of large-volume copies is possible.

The third mode is called "memory input mode," which allows the RM to be input without operating the printer 10-3.
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 R,
An overlaid copy of the image stored in the MU's memory is obtained.

“Memory high speed mode 0 has three modes inside the RMU: “retention mode” and “output mode”.
, ``Through-out mode''. ``Retention mode'' is a mode in which the image information (signal) from the first sheet of ``Memory High Speed'' original is compressed into memory and passed through to the printer. ′ Successful compression into memory by running retention mode.

Failure (RMU memory overflow) can be determined. League was successfully compressed into memory due to an error unit request command during copy operation.

If you can get the failure information (RMU memory overflow) and the compression to memory is successful, then the next copy (
Image formation (from the second image onward) is performed using the expanded image from the memory.
The league will stop scanning manuscripts because they can be copied (copied). 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 images from the R and MU memories to the printer.

The mode in which the selector is reset in this way is called "output mode." Conversely, if compression to memory fails, "retention mode" will compress the image to memory and pass through the image. 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 pass mode", but the image information from the league is a binary image with the same threshold generators A and H. On the other hand, the latter is a ternary image with VDA and VDB independent, so the name has been changed. This change in RMU internal mode causes RM
U outputs a binary image regardless of the success or failure of image compression to memory at “Memory High Speed 0, and 1
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 reader operation will be explained using chart 70 in FIG.

First, when the copy key is pressed by the operator, the reader issues an RMU instruction command (8-
103-1), number of sheets instruction command (8-103-2),
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 RINT to RMU (S-103-1'
O). Furthermore, start the timer (S-103-11
), S-103 should wait for a certain period of time until this timer out.
-1'2), the optical system is not started when the RMU internal mode is "output mode" (S-103-1
4) Count down the number of sheets, check whether the number is 0 (S-103-20), and if it is 0, output a printer stop command (S-103-21).

When the RMU internal mode is other than "output mode ll," scan the optical system (S-103-1
5) Start reading the original (S-103-16)
Output the image to R and MU. 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 (8-103-21).

In cases other than “Memory input mode” and “Output mode”, count down the number of sheets (S-103-
19) If the number of sheets is 0, a printer stop command is output, and if 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 from the league side (including the RMU) (8-104-1), the printer starts various operations such as drum charging (S-104-2). When the printer is ready to feed paper (S-104-3)
, output PREQ to the reader side (S-104-4),
If the league side inputs PRINT in response to PREQ (S-104-5), paper feed (S-105-6)
I do.

When paper is fed and images can be received (S-104-7),
Output VSRBQ to the reader (S-104-8). V
Corresponding to SRBQ, the VSYNC reader outputs an image signal (8-104=9).

The printer performs copy processing (S-104-710).

Check if there are any errors and (S-104-11
), if there is an error, the error is transferred to the serial communication (s-1o4=12). If you repeat the above operation for one copy, the league will output a printer stop message, so check whether the printer stop message has been received.5-ro4-
ta) Upon receiving this, the printer stops each part of the printer (S-104-14).

Before explaining the operation of the RMTJ, the memory address management of the 3MU will be explained using FIG. 28. When storing compressed image information in the memory, the RMTJ can set an arbitrary address on the memory as a compressed image write start address (hereinafter referred to as MS) and a maximum compressed image write address (hereinafter referred to as ME). RMU is M
The success or failure of writing a compressed image to memory can be determined by setting S and ME, and it is also possible to protect previously written image information.

Since memory is limited, this maximum value is set as MLMT.

FIG. 28(1) shows a state in which no image is written to the RMU. At this time, MS←0. M.E.
4-Set MLMT. This also indicates the maximum free space available in memory. When memory A is selected by the R, MU memory instruction command and an A4 size copy is made in dither memory high speed mode, R, MU is as shown in (2). Information on whether the mode was compressed (
MA-VIDEO), compressed image original size (MA-VIDEO)
-PSZ), reader reading mode (MA-METH)
OD), memory A image writing start address (M
AS), image write end address of memory A (MA
E). These pieces of information are written in the same way when writing to memory B and memory C, and if no image has been written, it is assumed that the corresponding information has been written.

The state (3) is the state in which memory B and memory C are written in the state (2). Memory B in state (2)
Or, when writing to the memo IJC is instructed, the area ■ in state (2), which is the maximum empty area, is written to the MS4-MAE+
Configure as 12ME4-MLMT. At this time, if memo IJA is designated again, the area including the upper and lower empty areas of memory A is set as new MS←O, ME, MLMT. By setting in this way, it is the same as when memory A is specified in state (1), and the memory can be used effectively.If memory A is specified in state (3), the memory in state (3) is There is no continuous empty area in IJ A, and the memory amount of memory A is compared with the empty area ■Ω memory in the state (3) by 1, and the one with the larger memory amount is set as the new memory A area.・In state (3), the empty area ■ is larger, so MS4MBB+1
, ME 4-MLMT, and the old memo IJ, A area is set to be empty.

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, M8←O, ME 4-
M'CB-1 is set, and the old memory B 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 the states of (5) and (6), the memo IJA
.

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. The amount of memory for this empty space is MA8
, M.B.S., MC8, MAR.

Reasonable memory management can be performed by calculating from MBE, -MCE. Even if MS.

MA-V:IDEO even if writing the image to the new area set in ME fails (image compression error).

By setting the contents of MB-VIDEO and MC-VIDEO to mean no image information and recognizing them as empty areas, rational memory management can also be performed. In this embodiment, the number of designated memory areas is set to "3", but it can be realized by changing the number of designated memory areas to "N"" depending on the amount of memory.

The following will explain the retention mode of the RMU mode as shown in FIG. 13, with reference to the flowchart in FIG. 7 Q
mm, sub-scanning direction 1. 1 from the point after 00mm
An example will be explained in which the image information B of 40 mm x 210 mm is trimmed and output. The RMU inputs Table 20 as the second byte of the RMU mode instruction command. Bit 6 and bit 5 are used to make the output density of the league image and RMU expanded image approximately 50%, respectively, and both are set to "1", and the RMU mode is set as shown in 104-2 in Table 5. Bit 4. Bit 3. Bit 2. Bit 1 is set.Memory A is specified as the memory instruction, and the 21st bit is specified as the RMU memory instruction command.
Enter the table. RMU) Main scanning compression start position Hp (70m
m), RMU) 'J M>G instruction command 2 trimming data is the sub-scanning compression start position Vp (100m
m), RMU) During main scanning compression I(w (140mm), RM
U) The trimming data of the rimming instruction command 4 in which Vw (210 mm) during sub-scanning compression is set is output from the league in millimeter units (S-106-
A-1).

Controller 1'0-2 converts the above position information from the league into bit units/line units, and converts it into Figure 13 where Hp=1102 bits, Vp=1.574 lines, Hw=2204 bits, and Vw-=3307 lines. Obtain the corresponding compressed image position/size information.

Directed 11. Depending on the MU mode, selectors 5ELL (10-18) and 5EL2 (10-19) in Figure 10
), 5EL3(i, o-2o), 5EL4(10-21
).

5EL5 (10-22), video selector (10-23)
) are respectively Tt, -VCLK, R, -VDA,
R'-VE.

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

In order to binary-compress and store the league image signal in the compressed image memory, the dither signal in FIG. 11 is set to L level. R.M.U.
Since the mode is "1 memory high speed mode" (R, MU internal mode is "retention mode"), the printer start command output 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 paper5.
-106-A-5), output this signal to the league (
S-106-A-6). At this point, the first frame of "Memory High Speed Beat Mode" is being executed (S-10
6-A-7), input a paper size instruction command from the league to specify the output paper size S-106-A-8);
It is 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 to the memory address counter 10-8 and the converter 10-.
It will be held on the 14th. The down counter 13-1 of the dither counter shown in FIG. 11 has the top 10 of 1245H (4677).
Bit 248H (584) is still down counter 1.
The lower three bits 5H (5) are set in 3-2. Similarly, in the main scanning counter and decoder shown in FIG. 12, 1'245H (4677) is set in the down counter 14-1. Note that comparator 1'4-2.14-3 is used only during decompression, so no settings are made, and comparator 14-4.1'
The comparator 4-5 is DF 7 H (
3575) and Hp, Hw, 5 sBH
(1371) and operate DADR at the same time as HADR, comparator 14-8 has 1245
Configure H (4677).

When the RMU receives the PRINT signal from the league (S-
106-A-10), output to printer (S-106
-A-12). When the VSREQ signal is input from the printer (S-106-A-13), it is output to the reader (8
-103-A-14).

At this point, the RMU mode is "Memory high speed mode".Since this is the first memory, the RMU mode is "Memory high speed mode".
Retention mode “Bifurcate (S-106-A-
18). Then, in Fig. 30, VSY from the leader
If you input NC ON (S-106-F-1),
Turn on and select Yellow > Evening (DV8YNC1tt > (S-1
06-F-2), do. Figure 13 vp 626H to 10-11 line counter to generate 1574 lines
(1574) and when the line counter counts up (5-106-F-4), the sub-scanning compression section signal V-ENC is turned on (8-106-F-5).

During sub-scanning of area B in FIG. 13, set the VW3307 to the line counter (S-106-F-6). By setting the selector described above, while passing the image from the reader through the printer, 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 (S-106 -F-7, S-1
06-F-8). When a count-up of the line counter 10-11 is detected, which means the end of image compression for a predetermined number of sub-scanning lines, the V-ENC signal is turned off (S-106).
-F-9), if the VSYNC off state from the reader is input (S-106-F-10), the VSYNC to the printer is
Turn off SYNC (8-106-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 transmitted to the reader through serial communication during the aforementioned copy operation. Based on this information, the reader determines that the retention operation using the compression memory is at the lower end, and repeats the image output by scanning the second and subsequent documents, and ends the copying operation. With this function, even if the image signal from the reader does not fit into the compressed image memory, copies of the number of stages can 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 bus mode', and does not turn the V-ENC signal on (from L level to H level) or off (from H level to L level) in response to the reader's VSYNC. Therefore, the RMU does not perform compression operation, the selector and counter are set to "retention mode", and when VSYNC from the reader is input, VSYNC is output to the printer. Figure 33, S-106-
D-1, S-106-D-2), passing the image from the reader directly to the printer S-106-D-3), and waiting for VSYNC from the reader. (S-106-D-4)
, VSYN to the printer if VSYNC is input
8-106-D-5), and when the reader has completed outputting image information for the set number of sheets, it issues a printer stop command and stops the link. The RMU ends the copy sequence by inputting this printer stop command (S-106-C-6).

Conversely, if the MOVER signal is at the L level, the writing to the memory was successful, so this is notified to the reader via serial communication, the reader 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,
7, the counter must be reset,
Reset the “output mode” as shown below (
S-106-C-4, S-106-C-5). Figure 10 5BLI, 5EL2.5EL3゜5EL4.8EL5
, video selectors are I-CLK, DVDO,
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 was extracted from the memory areas specified by Z, MB-PSZ, and MC-PSZ and compressed and stored is 2204
3307, the down counter 1 shown in Figure 12
4-1, 12F4H (4852), 14-2, 14-3.
1247H (4679) and 2
H(2).

1247H (4679), 9ABH (2475), dF
9H (3577), 55dH (1373), 1247H
(4679), and the "output mode" sets the decompression error counter 10-35 to 0 in order to perform decompression from the compressed image memory. Set IH (1) and IBFH (447) in the down counters 13-1' and 13-2 of the dither counter shown in Figure 11, respectively (S
-106-C-5).

The reader recognizes that there is no RMU memory overflow by the error unit status request command, and stops document scanning. The leader is VSY
Since it does not output NC, RMU receives VSYNC from the reader.
VSYNC to the printer is turned on without waiting (S-106-D-1). In addition, the sub-scanning direction margin Vp1
Set the line counter to count 574 lines (8-106-D-2), and if the line counter is up (S-106-D-4), V-DEC
Turn on the signal and set the number of sub-scanning lines for ■W, 3307 lines, in the line counter.S-106-D-5) Expand the image and check for expansion errors until the line counter ends (S-(o6-B- 22,8-106-B-23
). In this embodiment, if eight or more decompression errors occur, the decompression error flag is set to - and the copying operation is stopped. The RMU notifies the reader via serial communication that the decompression error has occurred a predetermined number of times (8 times), and the reader does not output any paper feed commands (PRINT) after determining that the decompression error has occurred more than the predetermined number of times, and stops the copy operation. stop.

In order for the RMU to stop the expansion operation, first turn off the V-DEC signal (5-106-D-s), set the number of sub-scanning lines for VR, and after incrementing the line counter, send VSYNC to the printer. I'll turn it off. The reader outputs a printer stop command to notify the printer of stopping the copying operation, 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 reader (S
-106-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 three values from the reader are directly transmitted to the printer without being stored in the compression memory.

That is, in the memory path mode, A1- and B1 of the selector 10-23 in FIG. 10 are selected.

In addition, the selector 10-18 is selectively operated to set the R-VCLK from the reader to 08YS, and the selector 10-22 is also operated to set the P-BD from the printer to H8YNC (S-106-A-2 ).

After this, the control signal coming from the beamer goes to the printer.
Furthermore, control signals coming from the printer are output as they are to the reader, and the RMU operates as if it were not present. In other words, when VSYNC from the reader turns on (
S-106-D-1), turn on VSYNC to the printer, and pass the image from the reader to the printer through the selector 10-23 (8-106-D-2゜S
-106-D-, 3). And VS from the leader
If YNC is turned off (8-106-D-4),
Turn off VSYNC to printer S-106-D-5
), and if a printer stop command is 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, we will explain an example in which an image written to compressed image memory in "memory input mode" is combined with an image from a reader in "memory overlay mode" and output to a printer. - As the first step in performing memory overlay operation. Image information must be written to the memory.The RMU mode for writing image information to this memory is "memory input mode".Trim area B in Figure 13 to create a memo IJC. RM when compressing and storing in area
The U instruction is the second byte of the RMU mode instruction command shown in Table 20, the second byte of the R,MU memory instruction command shown in Tables 21, and the reader operation by the operator as shown in Table 24. Based on the trimming area designation data of <R, MU,) Rimming instruction 1 command to R, MU) Rimming instruction 6 commands' trimming data contents are input from the reader. In the "memory input mode", 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, so the 5ELL shown in Figure 10 does not need to be output to the printer.
, 5EL2, 5EL3, 5EL4゜5EL5, video selector selection is R-CLK, I(,-VDA
, R-VE, R-VB, H8YNC.

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 R and MU, but R and MU output the PREQ signal to the reader instead of the printer (8-106-A-
4, S-106-A-6). By serial communication from the reader.

If the paper size instruction command is received, ・Memo IJ
Since C is specified, M is stored in the memory of the control unit of the RMU.
The paper size is stored and held in C-PSZ (paper size of memory C), and the fact that it is a binary image is also stored and held in MC-METHOD (reading mode of image information stored in memory C area).

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 (14-4) has 3575 from Hp.
14-5), 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) has the aforementioned MS (compressed image writing start address), and the comparator (10-14) has the ME (
Compressed image maximum write address) (8-
106-A-9).

Even if the R and MU input the PRINT signal from the reader (s
-t'o 6-A-10), since the printer does not perform a copy operation, it does not output to the printer, and instead of the printer, outputs the ■5RIEQ signal to the reader (8-106-A
-11, S-106-A-14). V8YN from the leader
When C on is input (8-106-B-1), the line counter (1'0-11
) to set Vp (8-106-B-2). S- to detect that the line count has increased.
106-B-3), V -E to start the compression operation
Turn on the #C signal (S-106-B-4). Also,
During sub-scanning to be compressed, Vw (3307 in this example) is set in the line counter (S-106-B-5). Then, the compression operation is repeated in the compressed image memory until the line counter counts up (8-1, 06-B-6
, S-106-B-7). To detect that the line counter has counted up and stop the compression operation, V-
ENC signal ttt7f (S-106-B-8). After that, in order to detect that the V8YNC signal from the reader has turned off (S-106-B-9), check whether there is a memory overflow (the memory address counter has exceeded the maximum address for writing compressed images). MOVER,
Signal detection is performed (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 compression failure information (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. If compression still fails, M
C-PSZ (paper size of memory C), MC-METOD
(reading mode), MC8 (memory C start address), MCE (memory C end address), MC-VI D
'EO (ffl contraction mode)'') (7) Memo information 'J
Make the same settings as if nothing had been written to C. This allows the specified memory area when compression fails to be recognized as an empty area and to be used effectively for the next compression operation. On the other hand, when compression is successful, MC8, MCE, MC-ME
THOD.

Stores information necessary for MC-VIDEO, 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 JtMU ends the sequence processing.

Now, with the input mode mentioned above, for example, the memo IJ
Assume that A4 size image information is compressed and stored in B. Then, consider decompressing this image information in "memory overlay mode", combining it with the image information of the league, and outputting it to the printer. By setting the parameter to 0'', the printer outputs the density at about 50%.Also, the main scanning size of the expanded image is Hw bits, using the point of Hp bits in the main scanning direction and Vp bits in the sub-scanning direction as a reference point. , the second byte of the RMU mode instruction command when trimming the image area of the sub-scanning size VW bits and outputting it to A4 size is the one in Table 25, and the E
t, MU memory instruction command 2nd byte of Table 26, RMU) Rimming instruction command 1 to RMU
) Assuming that trimming data 1 to trimming data 6 of rimming instruction command 6 are converted into bits or lines, Hp, V'p, HW,
The values Vw, HM, and 7M are 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-VE, P-BD.

A3. B3. , and set the Dither signal 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 PR, EQ multiplied signals PRINT signal and VSREQ signal are processed in memory pass mode. Or, it is omitted as it is the same as “Through Out Mode”. Convert the stored paper size and trimming data to bits and lines. Set the counter using LJcHp, VP, HW, VW, HM, and VM as follows. Comparator 14
4677 for -4, comparator! 01 for 4-5, 4677 for comparator 14-8, down counter 13
-1, 13-2 has 4677-(Hp -MM),
If the moving direction of the 4677 image is the same as the sub-scanning direction, the counter 14-1 inputs VSYNC ON from the league (S-106-H-1), and at the same time inputs the VSYNC to the printer.
Turn on YNC, (S-106-H-2), V-DEC
From VSYNC that outputs the signal to the printer (VM-Vp
) When the line is late, set the line counter to set it to H level (S-1o 6-I-(-3). After the line counter is up (S-1'06-H-4), the sub-scanning Vp line In order to bring the molecular R and M signals to L level,
Set IF'F11i'H in the comparator 14-6 and 4677 in the comparator 14-7.

4677.4677-( for HADR and DADR respectively)
HM-Hp) S-106-H-5), V
- CB-106-H-6) that turns on the DEC signal.

Set TR and M signals for trimming (S-106
-H-7) After setting the counters for the L and Vp lines and counting up (S-106-H-s, s 10
6 H9), set the TMR signal so that image expansion is performed S-106-H-10), set the Vw line to the line counter 8-106-H-11), IJ-
After compositing the image and the expanded image and performing the compositing operation for Vw lines (S-106-H-12), turn off the V-DEC signal to stop the expansion operation (S-10
6-H-14).

Next, in order to trim the T area, comparators that generate TRM signals are set, and as shown in FIG. S-
106-I-10).

As a result, the T area is outputted onto the copy paper from the location 11 in FIG. 22(C).

Next, the controller 10-2 controls the VW during sub-scanning of the T area.
The line is counted by the line counter 10-11.
106-I-11), the VD detects that the image signal of the T area is output to the printer and stops the decompression operation.
ECDEC signal f (S-106-I-12).

Now that the controller 10-2 has finished decompressing and outputting the compressed image data, it waits until all the images from the reader 1o-1 are output to the printer 10-3 (S-106-I-1
3) o! J-ta (D When it is detected that PVSYNC is turned off, VsYNc (
PVSYNC) to finish outputting one page of images to the printer 10-3 (S-106-I-14), and to check whether the set number of copies has been completed,
Proceed to FIG. 31 (S-106-C-6), which has already been described.

On the other hand, if the sub-scanning movement direction of the decompressed image T is opposite 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 V,=Vp from an A4 size image signal obtained by expanding compressed image data from memory.

When trimming the area T in the sub-scanning image where V2 = VW and moving it to a location at a distance v, = vM from the starting edge of the sub-scanning paper to t8, and combining the image signals from the reader and outputting it to the printer. corresponds to the controller 10-2
The following control operation is executed according to 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 11 by moving the T area in the main scanning direction H8 = HM, then the second
1, the load value of the counter 14-1 (HADR) is set to 4677° HAR, the comparator 14-4 which generates the EA multiplied signal is set to 4677°, and the comparator 14-5 is set to 0. The comparator 14-8 that starts the dither counter is set to 4677, and the dither counter 13
-1.Set 4677- (HM-HP) in 13-2 (S-106-I-1). Here, set O8YS to ICLK and Spe<5ELI (10-18), further set the start address of the compressed image data of U in the memory address counter 10-8, and
The signal is turned on, and U starts to decompress the image. Here, the line counter 10-11 counts the line length (Vp - VM) lines that protrude from the copy paper in the sub-scanning direction of the tJ side image (S-106-I-3), and -V-DEC
Turn off the signal and interrupt the expansion operation (8-106-I
-4).

Image decompression after this is performed using vSYNC(P) of reader 10-1.
O sys is R due to 5RCI (10-18) because it is performed using the clock of reader 10-1 in synchronization with VSYNC).
Select VCK. This can prevent pixels from being misaligned in the main scanning direction when the reader image and the U 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 IFFFH to the comparator 14-6 and 4677 to the comparator 14-7 (S-106-I-7). After this, in order to start the interrupted image expansion, the memory address counter 10-
Leave the value 8 as is and turn on the v-DEC signal. 1Q 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.

Although run-length encoding was used as the compression method in this embodiment, the image may be compressed by other encoding methods such as MH or MR encoding, and the storage capacity of the storage means is 3 It is not limited to one piece.

As explained above, according to the present invention, even if a compressed image cannot be stored in the storage means, image forming operation is possible, and inconveniences such as destruction of images already stored in the storage means are prevented as much as possible. It is possible.

Table 2 Table 3 Table 4 Table 5 Table 6 Table 7 Table 8 ′ Table 9 Table 10 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 drawings]

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 diagram showing the operation at the time of elongation error.
Fig. 9 is a diagram showing the trimming operation related to the main scanning direction and the image movement □ operation related to the main scanning direction, Fig. 22 (a),
(b) and (C) are diagrams showing the image movement operation in the sub-scanning direction, FIG. 23 is a flowchart diagram showing the procedure of serial communication of commands, and FIG. 24 is a flowchart diagram showing the procedure of serial communication of status, FIG. 25 is a flowchart showing the communication procedure before the copy operation, FIG. 26 is a flowchart showing the league operation, FIG. 27 is a flowchart showing the printer operation, and FIG. 28 is a diagram showing the state of the memory area. , FIGS. 29 to 36 are flowcharts showing the operating procedure of the RMU: 1-1 is the league, l-2 is the RMU, 1-3 is the printer, and 10-2
1 is a controller, 10-4 is a compression circuit, and 10-5 is a compressed image memory. 10-6 is an expansion circuit, 10-15 is a double buffer memory, 10-23 is a video selector, and 10-8 is a memory address counter. 70ri-U:tC toto

Claims (1)

[Scope of Claims] Means for outputting an image signal; means for compressing the image signal from the output means; storage means capable of storing a plurality of images of the image signal compressed by the compression means; and the output means. and means for forming an image based on the image signal from the storage means, and when there is no area in the storage means to store the image signal compressed by the compression means, the image signal from the output means is An image processing system characterized in that the image is supplied to the forming means without going through a storage means.