JPS61176265A - Picture processing system - Google Patents

Abstract

PURPOSE:To give the highly efficient compression even to a dither processed CONSTITUTION:The dither-processed picture signals are supplied from a reader as shown by 16-1.

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, with a resolution of 400 dpi, an A3 size image requires approximately 4 Mbytes to represent 2 (1 m signal).
image signals are used. Therefore, in order to store this image signal, a memory having a storage capacity of at least the same number of bytes is required.

Therefore, it is conceivable to compress the image by run-length encoding when storing the image. According to this, the data amount of a typical image can be reduced to about 1/10, and a relatively small capacity memory can be used. However, an image signal that has been dithered to simulate the halftones of an image has a small number of consecutive identical image signals, and if this is compressed by run-length encoding, for example, it will be smaller than the original image signal. The compressed signal may have a larger amount of data, and the storage capacity to store it will also be large.

The present invention has been made in view of the above points, and an object of the present invention is to efficiently compress an image signal that has been dithered to express halftones of an image in a pseudo manner. means for storing an image signal read out from the storage means; means for controlling storage and readout of the image signal in the storage means; and means for compressing the image signal read from the storage means; The present invention provides an image processing system that performs storage control and readout control of image signals in the storage means based on the periodicity of the image information and the size of the image information.

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 R and MU) -2, and an image forming device (hereinafter referred to as printer). It is composed 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;
There is a memory input function for storing the image signal read in RMUI1-2 in the memory of RMUI1-2, and a memory printout function for forming an image in the printer 1-3 from the image signal stored in the memory of RMUI1-2.

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

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

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

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

That is, the output from the A/D converter 3-2 is O~2
If it is 0, then vDA-0, vDB-0, and if the output from A/D converter 3-2 is 21 to 41 (il), then 1'j:
V D A ” 0, V D B = l, A/
When the output from D converter 3-2 is 42 to 63, V
DA=1. VDB=1, and the image signal from the original has three states depending on its reflection density: VDA=o, VDB,=
0, VDA=O, VDB=1, VDA=1. VDB=1
It is expressed as Therefore, the image signal is output from the reader in three values for each pixel. Note that it is also possible to make the threshold values from the threshold value generator A and the threshold value generator B equal, thereby outputting a binary image signal. Also, fd
The value comparators 3-5 and 3-6 can also generate a dither matrix threshold using a conventionally known systematic dither method, and thereby it is also possible to express halftones with ternary image signals of VDA and VDB. be.

RMUI-2 in FIG. 1 is an image storage device as described above. Inside, there is a compression circuit 1-2-1 that encodes and compresses the image signal from the reader, and a compressed image memo IJ that stores the encoded image signal.1. -2-2, and an expansion circuit 1-: 2-. which reads the compressed image signal from the compressed image memory 1-2-2, decodes it, and expands it into a bit-serial image signal. It consists of 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, and 4-2 is a laser driver 14- that converts an image signal into ON-OF'F laser light.
3 is a polygon scanner that scans a laser beam emitted from a laser driver 4-2 in the axial direction of the photosensitive drum 4-1, and 4-4 is an electrostatic latent image formed on the photosensitive drum 4-1 by scanning the laser beam. 4-5 is a print paper cassette, 4-6 is a print paper pickup roller that pulls out the print paper one by one from the print paper cassette 4-5, and 4-7 is a photosensitive drum 4-7 that carries the print paper. 4-8 is a transfer unit that transfers the toner image on the photosensitive drum 4-1 onto the print paper, and 4-9 is a transfer unit that transfers the toner image transferred to the print paper onto the print paper. 4-10 is a paper discharge tray from which the print paper with the toner image fixed thereon is discharged.

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

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

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

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

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

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

The video interface is an interface that connects the image output device 6-1 and the image receiving device 6-2, and the above-mentioned reader is a typical example of the image output device, and a printer is the image receiving device. 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. Video input signal (VE), which is a section signal of VSYNC11 line, which is a section signal, 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 white signal, the BD white 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, an image signal VDA of 1247 minutes is obtained.

Outputs VDB and section signal ■E. Signal VB.

The VDA and VDB images are synchronized with the clock VcLK, and in the printer, the VDA and VDB are ternary synthesized as a recorded image VD in synchronization with the clock VCLK.
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 (T) PR, DY) indicating that the control unit of each device is operating normally, a signal (PREQ) indicating that the output paper can be fed from the image receiving device, and an output from the image output device. A paper feed signal (PRINT) and an image request signal (VSREQ) from the image receiving device are transmitted. The control signals also include paper size information of the paper feed stage of the printer, 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 RMU 1-2 will be explained based on the above.

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

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

The format of the run-length code in this embodiment is (9-1) K as shown in 1 byte (8 bits), and the encoded data of the image is 7 in bit 6 to bit Q.
It is expressed in binary form of bits.

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

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

In the run-length method in this embodiment, the first 5 white bits appearing are encoded using a T code as in (9-3). The next 4,672 black bits are 128 or more, so they are composed of an M code and a T code. The M code is a binary representation of 36, such as (9-4), and the T code is (9-5). 64 is expressed in binary form as follows. In other words, M code (128X36) + T code (
64)=4672. As explained above, the above-mentioned 4677-bit one-line image signal is expressed by three bytes (9-3), (9-4), and (9-5).

Furthermore, the EOL:I code (End of Line code) shown in (9-2) is used as a signal to separate one line. This EOL code is like an M code because bit 7 is 1, but in the M code, bit
If 6 to blt □ are all 1, then 16256
This means a series of bit image signals. In this embodiment, the maximum data length of one line is 4677 bits, and bit 5 is always 0 in the M code, so
M where all bits are 1 in normal run-length encoding
No code is generated, and EOL codes and M codes are clearly distinguished.

Add this EOL code to the above white 5 bit black 4672
One line of an image signal of 4,677 bits is often written into memory as 4-byte data, which corresponds to about 17,146 of the original signal. Note that this encoding method does not have data indicating whether it is white or black in the code. Instead, 1
Line data always begins with a white code. The T code is also used as a code indicating data change from white to black and from black to white. If one line starts from black, a T code O representing white O is added in front of the black code. Furthermore, even if the sequence of images is exactly an integer multiple of 128 and can be encoded using only the M code, a T code 0 representing white 0 is added to indicate that the color changes.

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

Figure 10 is a diagram showing the detailed structure of Table 1.
The leader of 10 becomes the leader of 1-1 in Figure 1.
-3 printer is connected to 1-3 printer, lo 4 compression circuit is connected to 1-2-1, and 10-5 compressed image memory is connected to 1-3 printer.
-2-2 and 10-6 expansion circuits correspond to 1-2-3, respectively. 1o-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 the internal state of the RMU.

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

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

The decompression circuit 10-6 is a circuit that decompresses the run length code from the compressed image memo I710-5 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. Further, the EOL detection circuit is a circuit that operates only when the sub-scanning expansion section signal V-DEC from the controller 10-2 is asserted, and when the signal ①/DEC is negated, the output of the BOL detection circuit 10-7 is The buffer change enable signal yv (Buff CHG
ENB ) signal and data enable /l/ (Data
ENB) signal is fixed at high (H) level, and the DR
The P2 signal is fixed at low (L) level.

A memory address counter 10-8 performs an up-count operation to address the compressed image memory 10-5. This counter is configured such that a write/read start address can be set by the controller 10-2, and further, the counter output can be read by the controller 10-2. The count clock for this counter 10-8 is the compression circuit 10-4. Extension circuit 10-6, E
The DWP signal, DRP1 signal, DR, and P2 signals from the OL detection circuit 10-7 are applied through the NOR gate 10-29.

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

Two down counters, 11-3 and 13-2, totaling 13.
Bit address signal DADR to double buffer memory I
Supply to J 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 a compression/expansion section signal H-A RE A for each line;
Start signal DC8TAR of dither counter 10-10
Generate T or double buffer memo IJIO-'15
1ADR) and a signal (TRM) for trimming the image signal from the double buffer memory 10-15. 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 STA and RT signals. 14-2 to 14-8 are 13-bit comparators, each of which generates an A=B output when the value of the counter 14-1 is equal to the value set by the controller. 14-10 to 1'4-12 is 1 with flip-flop
It is set and reset by the outputs of comparators 4-2 to 14-7.

A comparator 10-14 compares the up-count output M-ADR of the memory address counter 10-8 with the set value from the controller 10-2. Comparator 1
The controller 10-2 controls the memory address counter 10 by the signal MOVER, which is A≦B output of 0-'14.
It is detected that -8 has reached the eight force value of comparator 10-14. In addition, in this state, the MOVER signal becomes logic state 1 (hereinafter referred to as H level), so that the CLK input of the memory address counter 10-8 becomes 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 memory X and memory Y each having one line worth of memory, and the memories X and Y have reverse read and write operations. This buffer switching is performed by inputting the BuffCHG signal, and the read address signal and write address signal are input from the dither counter 10'-10.
ADH and HADR from the main scanning counter decoder 1o-12 are used as appropriate.

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 YNC signal.

Reference numeral 10-1.7 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. BD double copy P-BD specified by the video interface from the printer 10-3
If the IBD signal is not input, selector 5EL
By selecting with 510-22, main scanning synchronization signal H8YNC inside RMU, BD double R-BD to IJ-Goo
used as

10-18 is a φsYs clock selector, which selects the video clock R-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 buffer 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 from the reader. The selection is made according to instructions from the double signal controller 10-2.

10-21 is a selector for pre-7tani line < VE double signal - VE, and the OVE signal corresponding to VE from the main scanning counter decoder and ■E double signal R-VB from the reader are specified by the controller 10-2. Select by.

10-22 is a selector for HSYNC as described above, and is selected according to an instruction from the controller 10-2.

10-23 is an image signal P- output to the printer 10-3.
Controller 10-2 with VDA and P-VDB selectors
controlled by AO of video selector 10-23,
The image signal R-VDA from the reader is connected to the BO large input beam, and by selecting the AO and BO large inputs, the image signal R-VDA and P-VDB from the reader are connected to both the image signals P-VDA and P-VDB to the IJ printer. VDA will be connected,
As is clear from FIG. 7, the recorded image VD output to the printer is a binary image.

Further, when A1 manual power and B1 manual power are selected by the video selector 10-23, the image signal R-VDA from the reader is output as the image signal P-VDA going to the printer, and the image signal R-VDA is outputted as P-VDBK. Image signal R-VDB from reader
(further AND game) 10-34, the signal is output.

The other input signal R- of this AND game) 10-34
HA L F 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- from the reader.
■The recorded image VD output to the reprinter with the same signal as DB is the image signal R- from the reader as shown in Figure 7.
The image is a composite of VDA and R-VDB.

The R-HALF signal is in logic state O (hereinafter referred to as "II L level")
), the image signal P-VDB going 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 A signal is recorded on the output paper. This means that when the R-HALF signal is at L level, the lighting time of the laser beam emitted from the laser unit 5-4 is approximately half that of when it is at H level, and the R-HALF signal is at L level. By doing so, an output image density of approximately 50% of the image signal from the reader can be 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 is passed through 0-27.10-28. Also, the image signal P-VDB going to the printer is the signal RMU.
-VD is further passed through an AND gate 10-32 to become a signal. The other input R of this AND gate 10-23
MU-HALF 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 the same signal as P-VDA. As shown in FIG. 7, VD becomes a binary image based on the image signal RMU-VD. If the RMU and -HALF signals are at L level, the image signal P-VDB going to the printer is fixed at L level.

In other words, the P-VDA has a double buffer memory 10-1.
The image signal RMU-VD from 5 is transmitted, but the image signal RMU-VD from P-V
Since DB remains at the L level, the image signal VD output to the printer is output as an image signal with a duty of approximately 50% for one pixel (one video clock) interval, as shown in Figure 7. recorded in This is RMU-HA
When the LF signal is at L level, the laser light emitted from the laser unit 5-4 is turned on compared to when it is at H level.
This means that the time is about half, and by setting the RMU-HALF signal to L level, an output image density of about 50% can be obtained.

When A3 human power and 83 human power are selected with video selector 10-23, OR game) 10-31. .

The image signal P-V goes to the printer by the function of 10-32.
DA, P-VDB[IJ-Gooka Rano image signal R
-VDA, R-VDB and double buffer memory 10-1
It is a composite of the image signals RMU-VD from 5.

Here, the image signal VD output to the printer by arbitrarily combining the R-HALF signal, RMU-) (ALF signal) described above is as shown in Table 1.

10=25 is the Buff from the EOL detection circuit 10-7
CHG ENB signal (double buffer switching permission)
This is a three-manpower ANT) gate that gates the LN-8T signal to generate a switching signal BuffCHG for the read buffer and write buffer of the double buffer memory 10-15.

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

(2) (Dither compression) An arbitrary part of the image signal R=VDA from the reader 10-1 is subjected to dither compression processing using the dither matrix threshold value to create a compressed image memo! A function to write to JIO-5.

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

(]) Binary compression function The image signal input from the reader is transmitted as an E-times signal synchronizing signal representing one main scanning line as shown in FIG. Then, the sub-scanning section □ for one page is expressed by the V'5YNC signal. The vE 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.

400 dots/1nch (4Q Q dpi) transmitted from the reader as shown in Figure 13 below.
A3 size (main scan 297 mm (4677 mm) of decomposed dust
7 Q mm in the main scanning direction and 100 m in the sub-scanning direction from the image information A of
An example will be explained in which image information B of 140 mm x 210 mm is trimmed and binary compressed from a point where m has elapsed.

Before receiving the above-mentioned image data from the reader 10-1, the controller 10-2 sets the mode of each section inside the R and MU.

Image signal R-VDA sent from reader 10-1
Clock +J used inside RMU to compress
Clock R-V from reader 10-1 as sys
Set 1O-18SBL1 to select CT and K.

Image signal R-VDA1 input from reader 10-1
The data is stored line by line in the d-carrier memory 10-15, and its output is input to the compression circuit 10-4.

Therefore, in order to convert the image data input to the double buffer memory 10-15 into R-VDA, 10-19SEL
Set 2.

Next, a synchronization signal Ll'1-8T for each line is set, and 1O-20SEL3 is set to use the R-vE multiplied signal from the reader 10-1. In addition, the reader 10-1 uses as a synchronization signal to generate R-VE.
As mentioned in the explanation of the video interface that the R-BD double signal is required, 10-22SEL5 is set to output the IBD signal from the horizontal synchronization signal generator 10-17 as the R, -BD double signal. do.

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

Comparator 1 sets the main scanning direction of area B in Figure 13.
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 in which this signal is at H level, and writes it into the compressed image memo IJiO-5.

Therefore, the comparator 14-4 is set to a value 3575, which is obtained by subtracting 1102 bits, which corresponds to a margin of 70 mm in the main scanning direction up to the area B in FIG. 13, from 4677. In addition, the comparator 14-5 has 140mm during main scanning of area B.
The value 1371 is set by subtracting 2204 bits corresponding to the minute from 3575.

The dither counter 10-10 starts to operate based on the output DC8TART from the comparator 14-8.
In order to operate the down counter 4-1 and the dither counter 10-10 at the same time, the comparator 14-8 is
I set 77.

The following constants are set for dither counters 1.0-10. That is, a count start value of 4677 is set in the counters 13-1 and 13-2, and the Difhe signal is set to L level in order to perform binary compression. As a result, 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 is both 11%-VB times 4 due to signal rise
It often counts down from 677.

That is, the compression circuit 10 from the double buffer 10-15
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 -DEC given to the EOL detection circuit 10-7 is at L level, D
'RPI signal D double signal 2 signal has L level, Buff
The CHG BNB signal and the DataENB signal go to H level, and the expansion circuit 10-6°EOL detection circuit 10-7 is configured so as not to affect the compression operation.

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

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

Line counter 1. n-11 counts down by the LN-8'l'' signal, that is, when the main scanning section signals R, -VB from the reader are input 1574 times, the line counter 10-11 sends the count up signal to the controller 10-2. The controller detects that the image signal from the reader has entered area B.Therefore, the controller changes V-ENC from L level to H level in order to cause the compression circuit 10-4 to start image compression. In order to measure the sub-scan length of 210 mm in area B, set 21 in the line counter 10-11 and 3307, which corresponds to 0 mm.

When the R-VE multiplied signal of the 3307th line outside the B area is input from the reader, the line counter 10-11 counts up again, and the controller 10-2 detects this and changes the V-ENC signal from the H level to the L level. to stop the image data compression operation of the compression circuit 10-4.

In this way, the image signal R-VDA continuously inputted from the reader 10-1 is output from the main scanning counter decoder 10-12 in the main scanning direction.
V-ENC generated by the controller 10-2 in the sub-scanning direction is trimmed to an arbitrary section of H level and encoded by the compression circuit 10-4, and the compressed image memo IJIO -5 is written.

This situation is shown in FIG. R-VD in Figure 14
A shows an example of inputting an image signal of one line, in which 2 bits of white, 2204 pits of black, and 5 bits of white are input as image signals in the trimming area of a certain line. A 5-byte run length code is generated in this R-VDA input compression circuit 1-4. That is, the first white 2 creates a 2H T code, then the black 22o4 creates an M code 91H, the T code 15H1, the last white 5 creates a 5H T code, and then G H-A R
An EOL code at the end of EA is generated and written into the compressed image memory 10-5 according to the write request DWP pulse from the compression circuit 10-4.

A memory address counter 1o-8 is used to address the compressed image memory 10-5, and is incremented by the signal passed through the DWP pulse counter 10-29, 10-30.

If the image signal R-VDA from the reader changes rapidly and a large amount of compressed codes MW codes are generated, a situation arises in which all the compressed codes MW codes cannot be written in the compressed image memo IJIO-5. Furthermore, when writing multiple pages of compressed image data to the compressed image memory 1-5 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, compressed image S (end address SE) and compressed image T (start address TS) are stored in 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 SB of the compressed image S.
, and the start address TS of the compressed image T is set in the comparators 10-14 as an address limiter. When the write progresses and the count output of the address counter 10-8 reaches the TS value of the comparator 10-14, the comparator outputs A≦B, and a new write request pulse is generated at 10-30. DWP is gated, the memory address counter is stopped, and further write operations are inhibited. This protects the compressed image T. The controller 10-2 has A≦ from the comparator 10-14.
Upon receiving the MOVER signal which is the B output, it is detected that the compressed image could not be completely written to the memory 10-5, an image compression error is detected, and the memory area where the image data was completely written is set as an empty area and the image is stored in the memory. output is prohibited, and a message to that effect is displayed on the reader display section.

The controller 10-2 moves the MOver at the end of image compression.
If the 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, and the address output MADR from the memory address counter 10-8 is read, and the end address of the compressed image written this time is determined. It is stored in the controller's internal memory as a file name and used to set the start address for writing the next compressed image.

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

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

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

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

In FIG. 16, the dithered image signal is (1,6
-1) is input from the leader 10-1). In this embodiment, one block has 8×8 dithers) IJ
The details are shown in block a of Figure 1 (16-2). If the image signal read from the reader is uniformly of 32 levels, a black signal will be output where the threshold value of the dither matrix is 32 or more.
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)
Eight state changes occur between four blocks of the VDA signal. The number of state changes is proportional to the number of blocks, and for A4 size 297 mm, 1168 state changes occur, resulting in an encoded data amount of 1170 bytes due to silan length encoding. This 1170 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 -4) As shown in EVDO, two state changes occur. As shown in (16-3), signals based on the same threshold for each block have little variation in black or white status, so by arranging them consecutively, the continuity of the image can be maintained. It will be extended.

In this embodiment, the arrangement of the image signal is changed according to the dither matrix by controlling the reading of the double buffer memory 10-15 using the dither counter 10-10.

The dithered image signal FLVDA from the readers is 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 10-15. This 8
Reading of the bit interval is done by the ])i ther signal from controller 10-2 shown in FIG. Controller 10-2 is still (16-1)
The comparator 13-20 calculates the value obtained by subtracting N-1 from the 13-20 counter setting value based on the main scanning compression block number N shown in
Set to 3. This number of compressed blocks N is the compression circuit 10-
H-AREA indicating the main scanning compressed data length given to 4.
It corresponds to the length of the signal (H-AR, EA signal bit length)=N×8.

In FIG. 11, when the i ther signal reaches the H level, the 3-bit counter 13-1 and the 10-bit counter 1
3-2 is separated, and the counter 13-2 counts down to the number N of blocks set in the comparator 13-3.
, the A=B output of the comparator 13-3 is generated, the counter 13-2 is reloaded to the initial set value, and the 1:3-1 counter counts down by one.

That is, the counter 3-2 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 N by the comparator 13-3, and can correspond to dither compression of an image signal having an arbitrary length in the main scanning direction.

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

First, in order to explain basic binary image decompression, we will assume that no trimming or movement processing is performed, and the compressed image signal from area B in Figure 13 is converted into a compressed image memo! by binary image compression. For example, assume that the compressed image is stored in J10-5 and that the compressed image is to be output to a location in area B of an A3 output sheet having the size of area A.

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 edge in the sub-scanning direction prior to outputting the expanded image of area B. That is, in FIG. 4, the printer is configured so that the distance from the transfer position of the photosensitive drum to the laser-exposed point ai is equal to the distance from b to the registration paper feeding point ci. The A3 output paper is sent out using the registration rollers, and after the sub-scanning paper is fed by 100 mm, the expansion operation is started, and the 8 images shown in FIG. 13 are output. Instead, the controller 10-2 outputs the registration paper feed signal VSYNC to the printer, and then outputs the line counter 10-11.
Set the number of lines corresponding to lQQmm to . This value is 1574 lines at a resolution of 400 dpi.

For the line synchronization signal LN-8T during image expansion, the BD double P-BD from the printer is selected by 5EL3 of 10-20 and 5EL5 of 10-22. Also, internal clock 0
8YS is the internal clock generator 1 in synchronization with HSYNC selected by SEL5 of 10-22.
I-CL K generated at 0-16 is 5 at 10-18
Select with ELI.

Now, with the line counter 10-11 mentioned above, the sub-scanning margin is 1.
After counting 1574 lines equivalent to 00mm, the controller outputs the image expansion signal V-DEC,
Before starting the decompression operation of area B, the address value set in the memory address counter 10-8 at the time of compressing and storing the image is set, and the final MADR value at the time of compression is set in the comparator 10-14.

The expansion circuit 10-6 expands the image line by line according to the DEC signal from the controller 10-2, and the expanded image signal DVDO is written into the double buffer memory 10-15, and after one line, is output to the printer. be done. At this time, dither counter 10-10 is double buffer memory 1.
It works as a write address counter for 0-15, and the main scanning counter decoder works 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 HA D R value is A, the above-mentioned left margin amount is applied to the grand counter 14-1 of the main scanning counter encoder-1, 0-11. Considering the value LMG (1,73 bits) corresponding to A+LM
G.

A is set in the comparator 14-2. A, -4676 for comparator 14-3, comparator 14-4
A to the comparator 14-5, A-2203 to the comparator 14-5, B to the comparator 14-6, and B to the 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 AK. 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
-8T signal is generated and the main scanning counter decoder 10-1
2 HADT%il: Count down from A+LMG, count the clock LMG, and when HADR becomes A, OVE signal, HAR, EA double signal DC8TA
An RT signal is generated.

This L M G is the number of clocks corresponding to the main scanning length from the printer's BD sensor to the image effective area 1 of the photosensitive drum. printed on top.

7 from HADR to A to area B in Figure 13
When HADR reaches B after counting 1102 clocks corresponding to the margin of Qmm, the TRM signal becomes I (level and the output image signal from the double buffer memory becomes G).
10-27, and HA D R becomes B
-22,03, the printer outputs 2204 pixels corresponding to 140mm during main scanning of area B, and TR
The M signal becomes L level, and the subsequent image signals sent to the printer are invalidated by game) 10-27. The expanded image signal stored in the double buffer memory in this way is output to the printer, and the double buffer memory 10-1
Writing an expanded image DVD to DVD 5 is as follows.

Simultaneously with the rising edge of 0■E, the H-AREA signal applied to the decompression circuit 10-6°EOL detection circuit 10-7 becomes H level, and the decompression circuit 10-6 starts decompression of the compressed image MR code.

The decompression circuit 10-6 reads the compressed image MR and the code from the compressed image memo IJ 10-5 in which the sub-scanning decompression period signal V-DEC and the main-scanning decompression period signal H-AREA are at H level, and sends the code to a decoding counter (not shown). Intake,
A decompressed image DVD is generated by counting down with the yIsYs clock. That is, as shown in FIG. 17, the T code 2H of the MR code is taken in and 5sys 2
Outputs a DVD of the clock white signal. osys
Every 2 clocks, the digital code counter counts up, generates the compressed image request signal DRP1, reads the next MR code from the compressed image memory 10-5, and outputs the DVD.
inverts the output of

The next MR code to be input is 91■ (because it is an M code, count the sYs clocks by 2176 clocks and then write the DR code.
Generate PI. However, since the M code and T code are a pair, the DVD is inverted at this point, and the DVD is inverted when the next T code 15H is counted up.

In this way, the image is expanded during the period in which HAREA is at H level, and the expanded image DVD is stored in the double buffer memory 10-15 by DADR from the dither counter 10-10.
O is written. Then, the count start value of the dither counter is set to B so that this DVD signal is read out from the eight points of the HADR in the next line. However, the dither counter in FIG. 11 is not capable of binary expansion. 1) The ither signal is set to L level.

The comparators 14-4 and 14-5 are set so that the HAREAAREA signal during image expansion and the same number of locks as the H-AREA used when compressing the B area image are output, but this HAR, EA multiplication signal When descending, the success or failure of the extension operation of the current line is detected by the E O'L detection circuit 1o-7.
Judgment will be made.

The success of the decompression operation is determined by the falling edge of the I-I A and REA signals, the fact that the next MR code is EOL, and the decode counter of the decompression circuit 10-6 counting up at that point. 3. DRPI signal is generated
This is done when two conditions are in place. Tore is a compressed image memo of the MW code signal from the compression circuit! This is because there is a possibility that an error may be included in the code when writing it to J10-5 or reading the MR code from the compressed image memory.If there is an error in the MR code, an accurate interval signal HA R, The end of EA and the generation of the DRPI pulse, which is the end of the expansion operation of one code, do not coincide with the line i completion code EOL. At this point, it is determined that the above three conditions match and there was no decompression error, and E
The OL detection circuit 10-7 generates DR, P2 so as to read out the first MR code of the next line for the next line.

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

In FIG. 18, the line synchronization signal PBD input from the printer 10-3 causes the main scanning address counter/decoder 10-12 to generate a main scanning expansion period signal regardless of V-DEC. 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 BuffCHG signal for switching the double buffer memory is always generated. It's a trench D
The ata ENB signal is at L level at this time, and the image signal RMU-VD output to the printer is output from the AND gate 10-.
28, it is fixed at L level.

Controller 10 = 21d V-DE to perform image expansion
Set the C signal to H level, and then HAREA1, HAR, E
A2. . . . The line-by-line image expansion operation is performed in the order of HA RE A 9 . During image expansion, the HAREA area is divided into three states. That is,
The state of the
This is level decompression error recovery state 2.

The next line HARE where the V-DEC signal becomes H level
Image expansion is started in the expansion circuit 10-6 from A1. As shown in FIG. 18, if an expansion error occurs in the first HAREAI (state y), the EOL detection circuit 10-7
is the rear end of HAREAL Bu'f CHG ENB
The signal and the DECENBi signal are set to L level, and in the next line HA REA2, the double buffer memory is switched and the expansion operation of the i-length circuit 10-6 is stopped, and EOL detection processing for expansion error recovery is performed (2 condition)
.

The EOL detection circuit 10-7 outputs an EOL code F as an MR code for the section where HAREA is H for decompression error recovery.
The DRP2 signal is repeatedly generated until FH is detected. By detecting the EOL code, the synchronization between the compressed image data and the Hl (and EA double signal) is restored, and the first MR code for image decompression in the next HAREA3 is read, DECEND is returned to H level, and decompression is performed. Terminates error recovery operation.

When the image decompression operation is normally completed in the next HAR, EA3 (state of X)', the EOL detection circuit qHAREA4
To read the first MR code of Nodame, I) Generate one clock of RP2, set the Buff CHG ENB signal to H level, and then output the LNST input after that.
The signal sets Data ENB to H level.

HAREA4. Since the image expansion operation has completed normally on both lines of HAREA5, Buff CHG E
Although the NB signal remains at the H level, an expansion error has occurred in HAREA6 as in HAREA1. In this state, the EOL detection circuit sends the Buff CHG ENB signal in HARE'A6 so that the decompressed image data containing the decompression error written in the memo IJY of the double bass sofa memory is not output to the printer. I-
Set to L level at the rear end of I AREA6, then HA11
．． In EA8, double buffer memory switching is prohibited when image decompression is successful. For this reason, HARE
In the section where the error is recovered in A7 and in HAREA8,
The section where the next expansion operation is performed is HA RE A 5
The image data with the expansion effect expanded in is repeatedly output to the printer as an RMU-VD signal.

In this way, the Buff CHG ENB signal causes the LN to be output after the expansion error occurrence line and the error recovery line.
If the Buff CHG signal is not generated by ST, the second
As shown in the RMU-VD signal in Figure 2, the extension success line (
Only the expanded image data in
It is output as a signal to the printer 10-3.

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

Further, the DataENB signal is configured to reach the L level one line later than the V-DEC signal becomes L level, and the expanded image in the last 9 lines of HAFtEA 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 BNB 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 for which decompression was not successful, and controller 1
For 0-2, if the number of lines for which decompression was not successful exceeds 8 lines, it will be immediately marked as a decompression error misprint.■D
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 signals V-D and EC output by the controller 10-2 are set to the same number of lines as when outputting the V-ENC signal during compression to the line counter 10-2.
11, it is counted and output.

Therefore, if no decompression error occurs during image decompression, the controller 10-2 controls the line counter 10-11.
■DEC upon receiving the specified sub-scanning line count completion output from
At the timing when the DEC signal returns to bell, the address output M-ADH from the memory address counter 10-8 becomes the same as the final value of M-ADR when the decompressed image is compressed.

Comparator 1o-i4 contains the final M-4L during compression.
Since the R value is set, the controller 10-2 is set to V.
The MOVER signal should be detected when the DECDEC signal is set to bell.

By the way, if a decompression error occurs during the decompression operation as described above, the EOL detection circuit 1 is activated to recover the decompression error.
0-7 should increment the EOL code (to skip the MR code, when the MOVER signal is generated, a remaining count is generated in the line counters 10-11. In order to count all the remaining counts, V- Even if the DEC signal continues to be output, the memory address counter 10-8 has already stopped counting due to the failure of the MOVER signal, so the image data at the address corresponding to the count value at the time when the memory address counter 10-8 stopped is repeatedly stored in the decompression circuit. 10-6, all remaining lines become decompression error lines.

Therefore, in order to prevent this situation, controller 10-
2 is ■DECDEC signal bell and line counter 1
% MO while waiting for count up from 0-11
Check the VER signal periodically, and if MOVER is detected when V-DEC is at H level, immediately set the V-DEC signal to L level, stop the image expansion operation, and count the extra expansion error lines. Try not to.

In this way, when the memory address counter matches the maximum address at the time of image compression, the image decompression operation is stopped, and unintentional extra image signals are sent to the printer 1o.
It is also possible to prevent it from being recorded in 3.

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

FIG. 19 shows a point t from point S1 of an expanded image U of A4 size, H1 bit in the main scanning direction and V1 line in the sub-scanning direction.
This is an example in which an image T having a main scanning size F1 of 2 bits and a sub-scanning size V2 bits is trimmed using 1 as a reference point and outputted on A4 copy paper without changing the positions of Vl and Hl.

As mentioned above, the expansion operation of one line is performed using the PB from the printer.
The operation is started using the LN-8T signal by the D signal as a synchronizing signal, and in FIG. 19, the expansion operation of one line starts when the HA D R from the main scanning address counter/decoder 104-12 becomes 4677. That is, I-
(ADR is 4677 and I-J-ARE A is H
14467 to comparator 14-4 so that the level is
Set 7. In order to finish the expansion at the A4 width of 4677 bits, comparator 14-5 is set to 0, and the length of 14 A RE A is set to 4677 bits. In addition, 4677 is installed in the comparator 14-8 that sets the output timing of the DC5TART signal so that the DADR that writes the expanded image signal DVD expanded by the expansion circuit 10-6 to the double buffer memory 10-15 and the HADR that reads it operate in the same manner. The LD value of counter 13-1.13-2 of dither counter 10-10 is also 4.
Set 677. As a result, the image signal compressed by U as described above is directly expanded.

As shown in FIG. 20, the controller 10-2 sends an A4 copy paper registration paper feed signal VSY to the printer 10-3.
At the same time as outputting NC, a sub-scanning expansion section signal V-DEC is outputted. As a result, the image expansion output starts at the same time as the printer feeds the paper, and if there is no need to perform trimming, by outputting ■-DEC for the same time as PvsYNc, the A4 size of U can be expanded. All images are output as is on A4 copy paper. Here, in order to perform the trimming as described above, the controller 10-
2 is %V1 In order to erase the image signal of the line, V
The TRM signal is fixed at the L level during the v1 line after outputting the -DEC signal, and the image signal read from the double buffer memory is fixed at the L level at 10-27. For this purpose, by setting IFFFH to the comparator 14-6 that outputs the TRM signal during one line count and 4677 (1245I()) to the comparator 14-7, , it takes only a reset.

(2) After counting one line using life counters 10-11, trimming of the T area of the V2 line during sub-scanning and the H2 bit during main scanning is performed from the tl position. For this purpose, the line counter IO-11 is set to the v2 line, the sub-scanning V2 line is calculated, and the comparator 14-1 is set to the line counter IO-11 to calculate the sub-scanning V2 line.
(4677-Hl) to 6, comparator 14
-7 is set to (4677-(H1+H2)).

As a result, TRM (V2) in FIG. 19 is obtained.

By setting the constants as described above, trimming of the T area between the iz point and the V2 line is realized.

When all the image signals in the T area are output to the printer,
A count end signal for the %V2 line is output from the line counter to-ii to the controller 10-2. 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 often needs to decompress the compressed image code in the shaded area, so it sets the VDECDEC signal to L level and stops the decompression operation. VDECDEC
Data from the EOL detection circuit is
The END signal becomes L level, and the image signal for the subsequent ■R line becomes a white signal (L level) to the printer, and T
Region trimming output is completed. In this way, by not expanding the compressed image code excessively, the number of decompression errors is reduced, which reduces the incidence of misprints caused by errors in the decompressed image, and improves copy operation. reliability is improved.

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

In this case, when writing the expanded image into the double buffer memory, the expanded image is moved by one line, and when the moved image is read out from the double buffer memory, the desired T portion is trimmed. The movement and trimming of this expanded image are all performed using 1, (ADR) as a reference. That is, in FIG.
-H,) to HA D R (4678 (II+ + H
2) The part of T expanded by the expansion circuit 10-6 in the address range of ) is written to the double buffer memory by DADR, and in (1)) of FIG. H when read
3-H, bits moved and HADR (4677-
The data will be read in the range from HA) to HADR (4678-(H2 + H3)). This image movement is DA,
It is executed by the address control of DR, and is executed as shown in FIG.
4677-H, which moves the pixels generated when the T part of the expanded image is written to the double buffer memory in a) (when HADR is 4677-IT) by Ha-Hl.
All you have to do is write to address a using DADR. That is, as is clear from FIG. 21(a), HADR=46
The count start value of DADR in 77 may be set to 4677-(Ha-Hz) by the number of main scanning movement bits I]3-H1. This Ha takes a positive value when the image movement direction moves away from the main scanning reference point (HADR=4677), and takes a negative value when it approaches.

The image signal read out from the double buffer memory is T
This TRM signal is also trimmed by the RM signal, but as shown in FIG. 21(b), considering the movement amount H3-H
2+N2), 4677 to H3 are set in the comparator 14-6, and 4677-(H2+N2) is set in the comparator 14-7.

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
-■ Since it is one line, the controller 10-2 is
After outputting the copy paper registration paper feed signal P-VSYNC to the printer 10-3, the line counter 10-
After counting V3-1 line in step 11, the sub-scanning expansion section signal VDEC is set to H level, and the expansion operation of the expanded image U is started. Here, the image of the T area is outputted using the TRM signal when one additional line has elapsed after the V-DEC signal is set to the I] level. Then, when the line counter counts 2 lines corresponding to the sub-scanning of the T area, the V-DEC signal is set to L level, and the expansion operation is completed.

Figure 22 (At the pick-up point, before register-feeding the copy paper, the expanded image U is expanded, and at line ■3 from the edge of the paper,
This is an example of outputting point P of a trimmed image, and when point ti is on the copy paper, ■3 takes a positive value, and when it goes outside the copy paper, it takes a negative value.

In FIG. 22(C), it is necessary to perform image expansion for vl-73247 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
After decompressing the image for 1-v3 lines, -VDEC
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 to continue the interrupted image expansion operation, and V, -732
47 minutes of image movement is performed.

Trimming of the T area is as described above, but if point P protrudes from the edge of the paper by 3 lines, the T area to be output on the copy paper will not be produced accordingly. Before outputting the PVSYNC signal, the image of the Vl-V3 line is expanded and the -carrier V-DEC signal is returned to the L level, but this is done in consideration of the case where RvSYNC from the reader is used as the PVSYNC. In other words, when overlaying an image decompressed by RMU with an image from a reader and outputting it to a printer, a common VSYNC signal must be used in order to accurately align the overlay position of the two images. do not have. However, VSYN from RMU to leader
Since there is no way to notify C, PVSYNCfd, IJ
- It is necessary to use VsYNc (R, VSYNC) from Goo. Reader and asynchronous controller 1
For 0-2, it is difficult to determine the detailed timing of when RvsyNC is input. Therefore, the controller 10-2 controls IJ-Guru et al. (7) VSYN
Sufficiently before inputting C (RVSYNC), V, -V
After the three-line image has been expanded, the MR code of the expanded image to be output on copy paper must be located at the beginning of the compressed image memory, and the expansion operation must be restarted in time with RvSYNC. That is, while waiting for RvSYNC, v-DEC is set to L level and the decompression operation is interrupted.

Note that when overlay operation is not performed, it is necessary to synchronize the breaker C, so 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, PVSYNC is immediately output without lowering the VDECDEC signal to the L level, and the decompression operation can be executed without interruption.

(4) Function of dithered image expansion If the compressed image by dither compression in (2) is simply expanded, the dither counter 10-1 at the time of dither compression
If the main scanning image is rearranged by 0 and expanded as it is, the copy output will be different from the original image. Therefore, in the dither image expansion process, the dither rearranged expanded image signal DVDO obtained from the expansion circuit 10-6 is processed in the same process as the binary expansion process in (3).
When writing 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 10-15 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. The Dither signal is set to H level, and the counters 1.3-1.13-2 are operated in the same way as during dither compression.

In this case, the counter load value set by the controller 10-2 in the counter 13-1. The load value of the counter must be the same as the value used during dither compression. Otherwise, the arrangement of pixels within one block of the dither pattern of the image signal read out from the double 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 reader, RM
The detailed procedures of serial communication between the U and between the RMU and the printer and the image processing operation will be explained below. Note that 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 reader, printer, n, and MU, and are controlled by reading the programs as appropriate. It is.

The serial communication shown in Figure 6 is 1) HvIOE in Figure 8.
Connect+DgvIcE, POWERR+e
ady.

When all units including the RMU become capable of serial communication due to the Controller Power Ready signal, the printer side unit (from the reader 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 reader side unit (including the RMU). Basically, when a command is input from the reader, the RMU outputs the same command to the printer, and when a status is input from the printer, the same status is output to the reader.

Serial communication between the reader side unit and 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 reader. This command is the RMU mode instruction command, RMU memory instruction command, and RMU
) Rimming instruction 1 command, RMU) Rimming instruction 2
command.

RMU) Rimming instruction 3 commands, R,MU) Rimming instruction 4 commands, RMU) Rimming instruction 5 commands)
, RMU) If it is any of the 6 rimming instruction commands (these 8 commands are collectively referred to as RMU instruction commands) (S-1, 00-1,), the 10th table below for 1 byte of each command. The body status is returned to the reader (S-1, 0O-5). If the input command is not one of the RMU instruction commands, R, MU determines whether it is a printer start command as shown in Table 1 100-1 (described later) (S-100-2).

The printer start command is issued by the system [If RMU is connected, the reader outputs the above-mentioned RMU instruction command after the reader outputs it, so at this point,
The MU mode has already been determined. If this RMU mode is "input mode II" described later, the printer does not perform a copy operation, so the RMU does not output this printer start command to the printer, but outputs the overall status shown in Table 10 to the reader (S-100 -3, S-10
0-5). In addition, for commands that include information necessary for RMU operation, such as paper size instruction commands, the contents of the commands are memorized and then output to the printer (S-100-4)
.

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

When the RMU inputs the status from the printer, it determines which command this status corresponds to, and
Check whether the application status is in Table 15 for the application status request command in Table 1.08-7 (S-1, 0l-1)
. If the input status is an application status, after adding RMU connection information (S-101
-2) Output to the reader as an 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, the error unit status with compression failure information (RMU memory overflow) is returned to the reader, and if the compression failure flag is reset, returns the error unit status from the printer to the reader 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, 5-101-9), if the decompression error flag described below is set, decompression error information should be added 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 as is to the reader.

In response to a command input from the reader, the RMU transfers the command to the printer or returns the overall status to the reader, and in response to the status input from the printer, it transfers the status to the reader or adds information to the status and then transfers 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 allows the leader to shorten the time for exchanging information and monitor communication, making it possible to simplify the communication protocol.

The reader and RMU are shown in FIGS. 23 and 24 below.

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

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

1'00-2 is a printer stop command 100-3 that requests the printer to stop copying, 100-4 is a paper feed instruction command that specifies a paper feed cassette, and 100-5 is a paper size instruction command that specifies the paper size. The second byte of this command (Table 2) uses bits 1 to 6 to A4. A3゜B4, B5, A4-R5B5-
Paper sizes such as R are encoded and stored. 100-6
is a number of sheets instruction command, and the second byte of this command uses 6 bits from bit 1 to bit 6 to specify a maximum of 64 sheets.
You can set the number of copies per sheet. 100-7 is the RMU mode instruction command, which is one of the RMU instruction commands.
Information on the RMU mode is stored in the byte as shown in Table 5. 100-8 is an RMU memory instruction command that specifies the memory area of the RMU, and stores the contents of the specified memory area in the second byte (Table 6), and sets only one bit of the corresponding memory area (" 1”).

1.00-9, 100-10, 100-11.

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

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

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

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 and RMU. Bit 5 is set when the printer is transporting paper ("1°゛). Similarly, bit 4 is set when there is a misprint, bit 3 is set to wait, bit 1 is set to operator call error,
Each is set when there is 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 size status in Table 14 is A4. B5. Information on the paper size such as B4, application status in Table 15 stores information on what kind of unit is connected to the system, and misprint detailed status in Table 16 stores information on misprints.

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

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

The league obtains RMU connection information from the application status in Table 15, which is output from the application status request command 108-7 in Table 9 (S-10
2-1). In addition, the paper size of the upper and lower cassettes of the printer can be determined by the cassette paper size status in Table 14, which is based on the output of the lower cassette paper size request command in 108-5 in Table 9 and the upper cassette paper size request command in 108-6 in Table 9. Obtain information (S-102-2). After this, 1 of Table 9
08-1 overall status request command 108 in Table 9
Obtain information on whether there is an error in the printer or RMU by outputting the error occurrence unit status request command in Table 10 and the error occurrence unit status in Table 11 (S-102-3, S-40
2-4). After this, it is checked whether there is an error (S-102-5). If there is an error at this time, please refer to Table 108-3, t Bellator Call Error Status Request Command Y, and Chapter 108 to obtain more detailed information.
- Output the service call error status request command in table 4, obtain detailed error information by inputting each status (S-102-6, S-102-7), and obtain necessary information such as paper out, RMU memory overflow. It is possible to notify the operator that there is a

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

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

In the league, RMU usage conditions (8-■) such as paper size selection (A-■), copy number setting (8-■), 9 image reading mode (A-■), RMU mode, trimming data, and RMU memory instruction are When the operator inputs an input from the league's operation panel and presses the copy key (8-■), the league sends an RMU instruction command (R,
MUMO t' instruction command, RMU memory instruction command (RMU) 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° Perform selector settings such as the video selector (C-■). Following the RMU instruction command, the league
Number of sheets command (B-■), upper/lower paper feed command 1' (
B7■) Outputs the 2 paper size instruction command (B-■). RMU manually edits the paper size instruction command (C-■
) and Figure 10 comparator.

Setting the dither counter, main scanning counter, etc. (C-■
). If the RMU mode is “memory input mode”, the RMU sends a printer start command to the printer.
RM is not flowing, so the printer does not output an output paper ready signal (hereinafter abbreviated as PREQ) to the RMU.
U sends PREQ to the reader instead of the printer (B
−■). When the RMU usage mode is not memory input mode, the printer start command reaches the printer, and the printer outputs PREQ to the RMU when it becomes ready to feed paper (D-■), and the RMU sends PREQ to the reader. and output it (B-■). When the reader receives PREQ from the RMU (from the printer), it outputs an output paper feed signal (hereinafter abbreviated as PRINT) to the RMU. (B-■).

When the RMU mode is "memory input mode°", PRINT is not output to the printer (D-■), as if the printer had input PR and INT and outputted an image request signal (hereinafter referred to as VSREQ) in response. The RMU outputs VSREQ to the reader (B-■).

When the reader inputs VSREQ from RMU, it outputs VSYNC (B-■) to output an image. The reader outputs an overall status request command and an error occurrence unit request command at regular intervals during the copy operation, 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, the RMU resets the mode (C-■)
and copying is completed.

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

The first is a mode called "memory path mode", in which the RMU outputs two image signals RVDA, 11 and VDB representing three values input from the reader 10-1 as they are to the printer 10-3, and the reader 10-1 and printer 10
-3 operates as if it 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 RV' from the reader 10-1.
The DA is compressed and stored in a compressed image memory, and then the compressed image data is continuously read out and output to a printer.

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

The third mode is called "memory input mode," 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 the RM
An overlaid copy of the image stored in U's memory is obtained.

``Memory high speed mode'' is set to 3 inside RMU.
There are three modes: ``retention mode'', ``output mode'', and ``through-out mode''. The data can be passed through to the printer while the data is being compressed into memory successfully by executing the ``retention mode''.

Failure (R, MU memory overflow) can be determined.

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

If 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.
copy), the reader stops scanning the document. The RMU resets the selector so that the memory can be expanded from the next copy. For example, the video selector 10-23 in FIG. 10 is reset to output the decompressed image from the RMU's memory to the printer.

The mode in which the selector is reset in this way is called "output mode." Conversely, if compression to memory fails, if you remain in "retention mode," the image will be passed through while being compressed to memory. Therefore, an operation that does not compress data into memory is required. This mode is called "through-out mode.""Through-outmode" has the same selector settings in the RMU as "memory pass mode," but the image information from the reader is a binary image with the same values for threshold generators A and H in the former. 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", 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, l'l, and MU internal mode.

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

First, when the copy key is pressed by the operator, the reader issues an RMU instruction command (S
-103-1), number of sheets command (S-103-2)
, upper and lower paper feed commands (S-103-3), 2 paper size instruction commands (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 to RINTt14LMU (S-103-1
'0). Furthermore, start the timer (S-103-1
1,), wait for a certain period of time until this timer runs out.
103-12), the optical system is not started when the RMU internal mode is "output mode" (S-103
-14), counts down the number of sheets, checks whether the number is 0 (S-103-20), and if it is O, issues a printer stop command (S-103-21)
.

When the RMU internal mode is other than "output mode", scan the optical system (S-103-15
), starts reading the original, (S-103-16,)
Send the image to RMU. After checking the completion of reading (, 9-103-17), if it is in memory input mode, the number of sheets is not checked (reading of one original is not accepted). A printer stop command is output to the RMU (S-103-21).

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

The printer operation will be explained using the flowchart of FIG. 27.

When a printer start command is input from the reader side (including the RMU) (S-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 pH'tEQ to the reader side (S-104-4
), if PR, I NT are input in response to PREQ from the reader side (s-1o4-5), paper feed (8-105
-6).

When paper is fed and images can be received (S-104-7),
Output vSREQ to reader (S-1048) o
V S RE Q K Corresponding L Te V S Y N C
Wo! J-da outputs and outputs an image signal (S-1,0
4-9).

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

Check if there are any errors and (S-104-11
), and if there is an error, the error is posted on the serial communication (S-104-1, 2). If the above operation is repeated for one copy, the reader will output a printer stop signal, so check whether the printer stop signal has been received.S-1o4
-13. ) The printer receives this and stops each part of the printer (S-1, 04-14).

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

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

Since memory is limited, this maximum value is set as M L MT. FIG. 28(1) shows a state in which no image is written to the RMU. At this time, MS←O
, ME4-MLMT are set in advance. This also indicates the maximum free space available in memory. R.M.U.
When memory A is selected by the memory instruction command and A4 size copy is performed in dither memory high speed mode, 11. As shown in (2), the MU contains information on which mode the RMU compressed the image stored in memory A (MA-VIDEO), and the document size of the compressed image (
MA-PSZ), reader read mode (MA-ME
THOD), memory A image write start address (MAS), memory A image write end address (
MAE). These pieces of information are written in the same way when writing to memory B and memory C, and if no image has been written, it is assumed that the corresponding information has been written.

The state (3) is when the memo IJ B and the memory C are written in the state (2). When writing to the memo IJB or memo IJC is instructed in the state (2), the area in the state (2), which is the maximum empty area, is stored in the MS.
Set as 4-MA, E +1, ME4-MLMT. At this time, if memo IJ A is specified again, the area including the upper and lower empty areas of memory A is set to a new MS, ←O, ME.
4-Set as MLMT. With this setting, it is the same as when memo IJ A is specified in state (1), and the memory can be used effectively.If memory A is specified in state (3), Since there is no continuous empty area in memo IJ A, the memory amount of memory A is compared with the memory amount of empty area (2) in state (3), and the one with the larger memory amount is set as the new memory A area. In the state (3), the empty area ■ is larger, so MS4-MBE+1. , ME←MLMT, and the old memo IJA area is set as an empty area.

The state (4) is the state in which image information has been written in the empty area (3) in the state (3). If there is a write instruction to memory B in this state, there is no continuous free space in the memory B area in state (4), and the memo IJ has the largest amount of memory among the B area, empty area ■, and empty area ■. The area is set as the new memory B area. At this time, if the empty area ■ has the largest amount of memory, then MS←O, ME←MC
8-1, and the old memo IJB area is set as an empty area. After this setting, if the image writing to the new memo IJ B area is successful, the state is (5), if the image writing fails, the state is (6), and if the compression to the memory fails, The written memory area becomes an empty area. .

In the states of (5) and (6), the memo IJA
.

Table 118 shows a comparison of the 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. yt moIJ amount t- for this empty area
MAs, MBS, MC8, MAR.

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

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

MB-VIDEO, MC-VIDEO (7) Contents:
By setting this to no image information and recognizing it as an empty area, rational memory management can also be performed. In this example, the number of memory specified areas is
However, the number of memory specified areas according to the amount of memory is ``'N°
It can also be achieved in °.

[An explanation of the "retention mode" of the 14MU mode is shown in FIG. 13, while referring to the flowchart in FIG. 29.
0 mm) from image information A in the main scanning direction,
140mm x 2 from the point after 100mm in the sub-scanning direction
An example will be explained in which a 10 mm image information B is trimmed and output. R, MU input Table 20 as the second byte of the RMU mode instruction command. Bit 6
, bit 5 are bits used to make the output density of the league image, R, and MU expanded image approximately 50%, respectively, and both are set to 1'', and 1 in Table 5 is set as the RMU mode.
Bit 4.04-2. Bit 3. Bit 2. Bit 1 is set. Memory A is specified as the memory instruction, and Table 21 is input as the RMU memory instruction command. RMU) As trimming data for rimming instruction command 1, main scanning compression start position Hp (70mm),
As the trimming data of the RM U l/rimming instruction command 2, the sub-scanning compression start position Vp (100 mm),
RMU) Hw (140mm) during main scanning compression as trimming data for rimming instruction command 3, RMU) Rimming instruction ml? The trimming data of command 4 with Vw (2], Omm) set during sub-scanning compression is output from the reader in millimeter units (S-106-A
-1).

The controller 10-2 converts the above position information from the league into bit units/line units, and creates a compressed image corresponding to FIG. 13 with Hp=1102 bits, Vp=1574 lines, Hw=2204 bits, and Vw=3307 lines. Get position/size information.

Depending on the designated R and MU modes, selectors 5ELL (1, 0-, 18) and 5EL2 (10-19) in Fig. 10 are selected.
, 5EL3 (10-20), 5EL4 (10-21).

5BL5 (,1O-22), video selector (10-2
3) are R-VCLK, R-VDA, and R-VE, respectively.

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 an L level Nissl signal. R.M.U.
Since the mode is memory high speed mode (RMU internal mode is 1' retention mode), it receives the printer start command output by the reader and passes it through to the printer (S-106-A-3). The RMU should input the PREQ signal that indicates the printer's paper feeding status.
106-A-5), output this signal to the reader (s
-1,06-A-6). At this point, the first image of “Memory High Speed Beat Mode” is being executed (,9-
106-A-7), input the paper size instruction command to specify the output paper size from the league. S-106-A-
8), 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, the aforementioned MS (compressed image write start address) and ME (maximum compressed image write address) are set in the memory address counter 10-8 and the humpator 10-1.4. The upper 10 bits 248H, (584) of 1245H (4677) are set in the down counter 13-1 of the dither counter shown in Figure 11, and the lower 3 bits) 5H (5) are set in the down counter 13-2. . Similarly, in the main scanning counter decoder shown in FIG. 12, the down counter 14-1 has 1245H (4677
) is set. In addition, comparators 14-2, 14
-3 is used only for decompression, so no settings are made, and 14-
4.14-5 comparator is DF7H which corresponds to Hp
(3575) and Hp, Hw corresponds to 55BH
(1371) and operate DADFL at the same time as HADR, comparator 14-8 has 1245
Configure H (4677).

When the RMU receives the PRINT signal from the reader (S-
106-A-10), output to printer (S-1,0
6-A-12). When the VSREQ signal is input from the printer (S-1,06-A-1,3), it is output to the league (S-103-A-1,4).

At this point, the RMU mode is "memory high speed mode".Since the number of memory is 1, the RMU mode branches to "retention mode" (S-106-A-1).
8). And in Figure 30, VSYN from the league
If you input C ON, turn on (S-106-F-1) and turn on VSYNC to the printer (S-106-F-1).
F-2). Figure 13 vp In order to generate 1574 lines, 626H (15
74) and when the line counter counts up (5-106-F-4), the sub-scanning compression section signal V-ENC is turned on (S-106-F'-5).

During sub-scanning of area B in FIG. 13, Vw 3307 is set in the line counter (S-106-F'-6). According to the settings of the selector mentioned above, while passing the image from the reader through the printer, the compressed image code from the compression circuit 10-4 is written to O-5 until the 10-11 line counter ends (S -106-F-7,S
-106-F-8). When the count-up of the line counter 10-11, which means the end of image compression of a predetermined number of sub-scanning lines, is detected, the V-ENC signal is turned off and S-1
06-F-9), if the off state of VSYNC from the league is input (S-106-F-10), VSYNC to the printer is turned off (S-106-Fll).

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,), MOV
If the IIR signal is at H level, writing to the memory is determined to be a failure, and a compression failure flag is set (S-106
-C-2) L. Information about compression failure (R, MU 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 its last stage, and repeats the image output by scanning the original for the second and subsequent sheets, and ends the copying operation. With this function, even if the image signal from the reader cannot fit into the compressed image memory, copies of several films can be output from the printer. At this time, the RMU makes the memory area where the compressed image was being written an empty area, and sets the RMU internal mode to "'" with the compression failure flag.
Change to through-out mode. “Through-out mode” is the same as memory pass mode, and V-ENC
Since the signal does not turn on (L level to H level) or off (H level to L level) in response to the league's V SYNC, the RMU does not perform compression operation, and the selector and counter are in parity mode. Once the VSYNC from the reader is input, send the VS to the printer.
Figure 33, S-106-D-1, S-
106-D-2), passing the image from the league directly to the printer S-1, 06-D-3), VSYNC from the league
You can wait. (S-106-D-4), VSYN
If C is manually operated, VSYNC to the printer is turned off (S-106-D-5), and when the league completes outputting image information for the set number of sheets, it outputs a printer stop command to stop the printer. The RMU ends the copy sequence by inputting this printer stop command (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,
Selectors and counters must be reset,
Reset the “output mode” as shown below (
S-106-C-4, 8-106-C-5). Fig. 10 5ELI', 5EL2, SBI, 3°SET, 4.5
EL5, video selector is I-CLK, DV respectively
DO, P-BD, OVB.

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 shown 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 designated by Z, MB-PSZ, and MC-PSZ, and compressed and stored, is area B in Figure 13, that is, 2204.
X 3307, so the down counter 14-1 shown in FIG.
-3.14-4.14-5.14-6. ．． 14-7.1
Comparators 4-8 each have 1.247H (46
79), 2H(2).

1247H (4679), 9ABH (2475), dF
9H (3577), 55dH (1,373), 1247
i((4679)), and the "output mode" sets the decompression error counter 10-35 to 0 in order to perform decompression from the compressed image memory.The down counter 1.3-1 of the dither counter shown in FIG. 11 Set 1.H (1) and IBFH (447) in .13-2 respectively (
5-1-06-C-5).

The reader recognizes that there is no error unit status request command - CRMU memory overflow, and stops document scanning. The leader is VS
Since it does not output YNC, RMU receives VSYN from the reader.
VSYNC to the printer is turned on without waiting for C (S-106-D-1). Also, the sub-scanning direction margin Vp
Set the line counter to count 1574 lines (S-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) Perform image expansion and check for expansion errors until the line counter ends (S-1,06-B) -22, S-106-B-2
3). In this embodiment, if eight or more decompression errors occur, a decompression error flag is set and the copy operation is stopped. The RMU notifies the reader through serial communication that the decompression error has occurred a predetermined number of times (eight times), and the reader does not output paper feeding commands (PR, INT) after determining that the decompression error has occurred more than the predetermined number of times. Stop the copy operation. In order for the RMU to stop the expansion operation, first the V-DEC
Turn off the signal (S-106-D-8), set the number of sub-scanning lines for Va, and after incrementing the line counter, turn off the VSYNC to the printer. 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.

R, MU if no decompression error occurred on class 8
repeats the expansion operation (set number of sheets - 1) times, and 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.

1n, that is, in the memory path mode, A I, , B 1 of the selector 10-23 in FIG. 10 is 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 reader is sent to the printer.
Control signals still coming from the printer are output to the reader as they are, and the RMU operates as if it did not exist. In other words, if VSYNC from the reader turns on (
S-IQ6-D-1L Turn on VSYNC to the printer, and pass the image from the reader to the printer through the selector 10-23 (S-106-D-2゜S-
106-D-3). And v SYN from the leader
If C is turned off (S-106-D-4), turn off VSYNC to the printer s-106-D-5),
If the print command is input, the print operation is stopped. On the other hand, if the printer stop command is not input, the same process is repeated for the set number of times.

Next, an example will be described in which an image written in the compressed image memory in the "memory input mode it" is combined with an image from the reader in the "memory overlay mode 1" and output to the printer.

As a first step to perform a memory overlay operation, image information must be written to the memory. The RMU mode for writing image information into this memory is the "memory input mode." RMU when trimming the B area in Figure 13 and compressing it into the memo IJC area.
The instructions are 2 of the RMU mode instruction commands shown in Table 20.
Based on the byte, the second byte of the RMU memory instruction command shown in Table 21, and the trimming area designation data from the operator's operation section of the reader as shown in Table 24, the <RMU) IJ trimming instruction 1 command from RMU)
Input the content of the trimming data of the rimming instruction 6 command 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.
2,5EL3.5EL4.

5EL5, video selector selection R-CL respectively
K, R-VDA, R-VE, R-VB, H8YNC.

Set AO and BO (S-106-A-2). Also, since the printer does not perform copying operations, P'FLE
Although the Q signal is not output to the RMU, the RMU outputs the PREQ signal to the reader instead of the printer (S-106-A
-4, S-106-A-6). By serial communication from the reader.

When the paper size instruction command is received, the memo IJC
is specified, M is stored in the memory of the control unit of R and MU.
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 the memo IJC 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 (sub-scanning width), HM (main-scanning movement position), and VM (sub-scanning movement position), the down counter (14-1) has 4677, and the comparator (14
-4) is 3575 from HP, comparator (14-5
) is 1371 from Hw, comparator (14-8) is 4677 from paper size, dither counter (14-1')
Set 4677 to . Memory address counter (
Set the aforementioned MS (compressed image write start address) in 1o-s) and ME (maximum compressed image write address) in comparator (1'0-14) (S-106-
A-9).

Even if the RMU receives the PR NT signal from the reader (S-
1'06-A-10), since the printer does not perform copying operations, it does not output to the printer, and instead of the printer, V'
Output the 5REQ signal to the reader (S-106-A-
11, S-106-A-14). Ritakara■5YNC
When ON is input (S-106-B-1), Fig. 17B
Vp up to the area (1574 in the case of nQ in this example) Set VP in the line counter (10-11) to avoid line compression (S-1
06-B-2). To detect that the line counter has counted up (S-106-B-3), turn on the V-ENC signal to start the compression operation (S-106
-B-4). Still, set the sub-scanning width VW to be compressed (3307 in this example) in the line counter (S-10
6-B-5). Then, the compression operation is repeated in the compressed image memory until the line counter counts up (S-
106-B-6, S-106-B-7). To detect that the line counter has counted up and stop the compression operation, turn off the V-ENC signal (S-106-B
-8). After that, detecting that the VSYNC signal from the reader has turned off (S-106-B-9), to check whether there is a memory overflow (the memory address counter has exceeded the maximum address for writing compressed images). , detects the MOVER signal (Fig. 31, 8-106)
-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 reader of compression failure information (S-1,06
-C-2). As a result, information about the RMU compression failure is added to the error occurrence unit status, and the reader recognizes the RMU compression failure. In addition, if compression fails, MC-PSZ (paper size of memory C), MC-MET
OD (reading mode), MC8 (memory C start address), MCE (memory C end address), MC-VI
The DEO (compression mode) information is set in the same way as if nothing had been written to memory C. This allows the specified memory area when compression fails to be recognized as an empty area and to be effectively used for the next compression operation. On the other hand, when compression is successful, MC8, MCE, MC-METHOD.

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

If a printer stop command is input from the reader (S-106-C-6), the RMU 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 from the reader, and outputting it to the printer.The decompressed image from the RMU's compressed image memory is Setting bit 5 to "0" outputs the image to the printer at approximately 50% density.Also, the decompressed image is scanned in the main scan direction using the Hp bit point in the main scanning direction and the ■P bit point in the sub-scanning direction as the reference point. When trimming an image area of size Hw bits and sub-scanning size Vw bits and outputting it to A4 size, the 2nd byte of the RMU mode instruction command is the one in Table 25, and the 26th byte is the 2nd byte of the RMU memory instruction command. From RMU trimming instruction command 1 to R, M
U) Assuming that trimming data 1 to trimming data 6 of rimming instruction command 6 are converted into bits or lines, Hp, VP, HW, VW, respectively.
, HM, VM are set and R, MU are sent from the reader.
Output Sarel for. The RMU is selected by selector 1 in Figure 10. Selector 2. Selector 3. Selector 4. Selector 5°,
R-VCLK for video selector selection.

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

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

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

If a paper size instruction command is input from the reader, it is stored separately from the paper size of the compressed image.
Processing of the PREQ signal, PRINT signal, and VSREQ signal is in "memory pass mode." Or, it is the same as the pass-through mode, so it will be omitted. The stored paper size and trimming data were converted to bits and lines. ) (p, VP, HW, VW, HM, and VM set the counters as follows. 4677 for comparator 1Q ri 14-4, 0 for comparator 14-5.
1 4677 for comparator 14-8, 4677- for down counter 13-1.13-2 (Hp -MM
), when the movement direction of the 4677 image is the same as the sub-scanning direction, the counter 14-1 inputs VSYNC ON from the printer (S-106-H-1), and at the same time turns on VSYNC to the printer, (S-106-H-2), V-
From VSYNC that outputs the DEC signal to the printer (VM
-Vp) Set the line counter to set the line to H level (S-106-H-3). After the line counter is up (S-106-H-4), in order to set the sub-scanning Vp line molecule RM signal to L level, the comparator 14-6 is set to IFFFHl.
Set 4677 to .

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

Setting TRM signal for trimming (S-106-
H-7) After setting the counters for the L and Vp lines and counting up (S-106-T(-8, S-106
-H-9), Set the TMR signal so that image expansion is performed S-406-I- (=10), Set Vw line to the line counter S-106-H-11), Reader image and expansion After compositing the images and performing the compositing operation for the Vw line (S-106-H-12), turn off the V-1-DEC signal to stop the expansion operation (S
-106-HLI4).

Next, in order to trim the T area, a hump parator that generates a T'RM signal is set, and as shown in FIG. Sur (S)
'-106-I-'10).

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

Next, the controller 1o-2 controls Vw during sub-scanning of the T area.
The lines are counted by the line counter 10-1' 1, 5-ro 6-I-1, 1), detecting that the T@ area side image signal is output to the blink, and DEc signal to stop the expansion operation. (S-106-I-12).

Now that the controller 10-2 has finished decompressing and outputting the compressed image data, it waits for all images of the reader 10-1 to be output to the printer 10-3 (5-106-I-1
3). When it is detected that the PVSYNC of the reader is turned off, the VSYNC (PVSYNC) to the printer 10-3 is
) off; to end the output of one image to the printer 10-3. Proceed to figure (S-106-C-6).

On the other hand, if the sub-scanning movement direction of the decompressed image T is the opposite direction to the sub-scanning direction, the process advances from (S-106-G-1) in Fig. 34 to Fig. 36, and the compressed image in Fig. 22 (C) Sub-scanning image positions V, -Vp from an A4 size image signal obtained by expanding compressed image data from memory.

Trim the area T in the sub-scanning image where V2'=Vw and move it to a location at distance ■3-■M from the starting edge of the sub-scanning paper to tl, combine the image signals from the reader and output it to the printer. This corresponds to the case where the controller 10-
2 or less control operations are executed as shown in FIG.

Main scanning image position H, -Hp of T area, 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 Hs = HM, the load value of the counter 14'-1 (HADR) is 4677° HA R as shown in FIG. , EA signals are set to 4677° in the comparator 14-4, and 0 is set in the comparator 14-5. 4677 is set in the comparator 14-8 that starts the dither counter, and 4677-(HM-HP
) (s-i06-I-1). here) O8
Set 5EL1 (1o-18) to set YS to ICLK, set the start address of compressed image data of U to memory address counter 1o-8, and read V-D.
Turn on the EC signal and start decompression for the 0th image. Here, the line counter 10-1'1 determines the line length (Vp-VM
) to count the lines S-106-I-3), -V-D
Turn off the EC signal and interrupt the expansion operation (5-10
6-I-4).

Image decompression after this is performed using vsYNC('
PVS'YNC) K synchronous siter 1゜-1O black"/
Since it is performed separately, 08YS selects RVCK by SEC'l (10'-18). This can prevent pixels from being misaligned in the main scanning direction when the reader image and the 0 image are combined.

In this state, when VSYNC is detected from the reader, the controller 1o-2 sends the registration feed K signal P to the printer.
V 8 Y N Ctt output '(S-1'06-I
-6), the TRM signal is set to L level so as not to output an expanded image during the VM line in sub-scanning.

This is achieved by setting IFFFH in the comparator 14-6 and 4677 in the comparator 14-7 (s-106-I-7). After this, in order to start the interrupted image expansion, the memory address counter 1o-
Leave the value 8 as it is and turn the '11 V-DEc signal O.
Make it n. Here, the line counter 10-1.1 counts the VM lines until the T image is output (S-106
-I-9).

In this way, R and MU operate according to the four mode specifications described above.

In this embodiment, the run-length coded image signal is stored as it is, but the run-length code may be further subjected to compression operations such as MH and MR. Furthermore, the image signal to be compressed may be one transmitted over a telephone line or the like.

As described above, according to the present invention, it is possible to efficiently compress and store dithered image signals, and since preprocessing for compression is performed according to the size of input image information, compression processing according to the size can be performed. It becomes 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 diagram showing the schematic configuration of the printer, 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, Fig. 8 is a diagram showing various signals of the video interface, Fig. 9 is an explanatory diagram of the encoding operation, Fig. 10 is a block diagram showing the detailed configuration of the RMU, and Fig. 11 is a diagram showing the detailed configuration of the RMU.
Figure 12 is a configuration diagram of a dither counter, Figure 12 is a configuration diagram of a main scanning counter decoder, Figure 13 is a diagram showing a trimming state of an original image, Figure 14 is a timing chart diagram showing an image signal compression operation, and Figure 15 16 is an explanatory diagram of dither compression, FIG. 17 is a timing chart diagram showing the expansion operation of the image signal, and FIG. 18 is a timing chart diagram showing the operation when an expansion error occurs. Fig. 19 is a diagram showing the trimming operation related to the main scanning direction and the image movement operation related to the main scanning direction, 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 operation of the league, Fig. 27 is a flowchart showing the operation of the printer, and Fig. 28 shows the state of the memory area. 29 to 36 are flowcharts showing the operation procedure of the RMU, in which 1-1 is the league, 1-2 is the RMU, 1-3 is the printer, 10-2 is the controller, and 10-4 is the compression The circuit includes a compressed image memory 10-5, an expansion circuit 10-6, a double buffer memory 10-15, a video selector 10-23, and a memory address counter 10-8. S-/θ6-1-6 =953-

Claims (1)

[Scope of Claims] Means for storing a dithered image signal, means for controlling storage and reading of the image signal in the storage means, and means for compressing the image signal read from the storage means. An image processing system, wherein the control means controls storage and readout of image signals in the storage means based on the periodicity of the dither pattern and the size of the image information.