JPS61176264A - Picture processing system - Google Patents

Abstract

PURPOSE:To obtain a picture output free from disturbance by supplying CONSTITUTION:When an expansion error is produced at an HAREA1, an EOL detecting circuit.

Description

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

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

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

Therefore, it is conceivable to compress the image when storing the image. According to this, the amount of data for a typical image is 1/1
This means that it is sufficient to use a relatively small capacity memory that can be reduced to about 0. However, the amount of compressed data is non-uniform depending on the image, and therefore the amount of data constituting one line is also not the same.

Therefore, when decompressing an image signal that has been compressed and stored in this way, for example, line synchronization must be maintained accurately, otherwise the decompressed image will be distorted. The present invention has been made in view of the above points, and aims to expand a compressed image signal and achieve an image output without disturbance. ,
means for decompressing the compressed image input from the input means; means for detecting an abnormality in the decompression operation in the decompression means; storage means for storing a plurality of lines of the image signal decompressed by the decompression means; means for outputting an image signal read out line by line from the storage means, and when the detection means detects an abnormality in the expansion operation of the expansion means, the image signal is stored in the memory in place of the expanded image with the abnormality. The present invention provides an image processing system that supplies a normal decompressed image signal stored in the means to the output means.

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, which includes an image reading device (hereinafter referred to as reader) 1-1, an image storage device (hereinafter referred to as RMU) 1-2, and an image forming device (hereinafter referred to as printer). )■-3.

The main function of this copy is to form an image using the printer-3 from the image signal read by the reader 1-1.

function, the image signal read by reader 1-1 is RMU1-
There is a memory input function for storing the image signal in the memory of the RMUI-2, and a memory printout function for forming an image in the printer-3 from the image signal stored in the memory of the RMUI-2.

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

As shown in FIGS. 2 and 3, the reader 1-1 uses a CCD line sensor 3-1, which has a light-receiving bare hand of approximately 5,000 bits, to separate the document on the document table 2-1 into a plurality of pixels. It reads each line and outputs bit-serial binary image signals VDA and VDB that indicate the density of the original image. In FIG. 2, the end of one line read by the CCD 3-1 is main scanning reading 2-2, and the movement of the main scanning reading line in a direction almost perpendicular to the main scanning direction is sub-scanning 2-3. .

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

゛That is, the output from the A/D converter 3-2 is O~
In the case of 20, vDA=0. ■DB=0, the output from A/D converter 3-2 is 21 to 41 (in case of D, 1dVDk=
O, VDB=1, A/D: Output from I inverter 3-2 is 42-63. In the case of VDA=1. VDB=
1 and: &! D. The image signal from the original has three states depending on its reflection density: VDA=O, VDB=O, VDA=
O, VDB=1, ■DA-1. It is represented by vDB=1. Finally, the image signal is output from the reader in three values for each pixel. Note that it is also possible to make the thresholds from threshold generator A and threshold generator B equal, so that 2
An image signal of the value is output. In addition, the threshold comparator 3
-5.3-1j: It is also possible to generate a dither matrix threshold using a conventionally known systematic dither method, thereby reducing V
It is also possible to express halftones with 3-valued image signals of DA, VDB.

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

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

The operation in which an image signal, which is an electrical signal, is visualized on printing paper in a printer will be described with reference to FIG. Two systems of binary image signals VDA and VDBi input from the video interface 5-11, and a 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 based on the VD signal by a semiconductor laser 5-4. The laser beam is focused by a collimator lens 5-5, and scanned by a polygon mirror 5-6 in a direction substantially parallel to the rotation axis of the photosensitive drum 5-2, which is rotated by a predetermined amount. The scanned laser beam is f~
The scanning position is corrected by the θ lens 5-7, and the photosensitive drum 5
-2 to form a latent image based on the VD signal.

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

Since the electrostatic recording method is a well-known technology, 1. Detailed explanation will be omitted.

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

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

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

The video interface is an interface that connects the image output device 6-1 and the image reception device 6-2.A typical example of the image output device is the above-mentioned reader, and an example of the image reception device is a printer. The image storage unit (RMU) -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 pit serial image signals VDA and VDB, as well as the line synchronization signal BD from the image receiving device as a signal for controlling the image signal, and the output image signal for one page from the image output device. A synchronizing signal consisting of a section signal VSYNC, a video input signal (VE) that is a one-line section signal, and an image clock ■CLK is transmitted.

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

Outputs VDB and section signal vE. Signal VB.

■DA and vDB are synchronized with the image clock vCLK, and VDAI! :VDB is clock V
In synchronization with CLK, the three-valued image is synthesized as a recorded image VD and transmitted to the laser driver.

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

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

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

The image signal from the reader is bit serial image information, so it is 400 dpi (400 dots per inch).
Image information read at a resolution of 3. on an A31 page.
It has a memory capacity of 7MB. Since the image information equivalent to 574 images in a U64-bit DRAM is unrealistic both in terms of implementation and price, 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 consecutive number of ``states'' or 6'' states by a counter is handled as an image signal, and the format of run-length encoding in this embodiment is shown in FIG.

The format of the run length code in this embodiment is composed of 1 byte (8 bits) as shown in (9'-1), and the encoded data of the image is expressed in a 7-bit binary format in bits 6 to 0.

Furthermore, in the 7-bit binary format, run lengths (consecutive numbers of 110) can only be expressed from 0 bits to 127 bits, so run lengths of 128 bits or more are expressed in 2-byte format. In this case, one of the two bytes is 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 is a make-up code (hereinafter referred to as M code).
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), b11 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 4672 black bits are 128 or more, so they are composed of an M code and a T code, and 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 code as shown below. That is, it is encoded as M code (128×36)+T code (64)=4672. As explained above, the above-mentioned 4677-bit one-line image signal is expressed by three bytes: (9=3), (9-4), and (9-5).

In addition, an EOL code (End of Line code) shown in (9-2) is used as a line separation signal. This EOL code looks like an M code because bat 7 is 1, but if bit 5 to bit O are all 1 in the M code, it often means a continuous 16256-bit image signal. . In this embodiment, the data length of one line is maximum 4677 bits,
Since bit 6 is always 0 in an M code, an M code in which all bits are 1 is never generated in normal run-length encoding, and EOL codes and M codes are clearly distinguished.

Add the EOL code to the above white 5 bit black 4672
One line of image signal of 4,677 bits is written into the memory as 4-byte data, which corresponds to about 17,146 bits of the original signal. Note that this encoding method requires that data indicating whether the image is white or black be included in the code. Instead, 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 0 representing white O is added in front of the black code. Furthermore, even if the sequence of images is exactly an integer multiple of 128 and can be encoded using only the M code, a T code O representing white 0 is added to indicate that the color changes.

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

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

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

A memory address counter 10-8 performs an up-counting operation to address the compressed image memory 1o-5. This counter is configured such that the controller 10-2 can set a write/read start address, and furthermore, the counter output can be read by the controller 10-2. The count clock of this counter 10-8 is the compression circuit 10-4, the expansion circuit 10-6, and the E
The DWP signal, DRPI signal, and DRP2 signal from the OL detection circuit 10-7 are applied through the NOR gate 10-29.

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

11-3. ! :'13-2's two down counters supply a total of 13 bits of address signal DADR to the double buffer memory 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, a section signal of compression and expansion for each line by the decoder) (-AI (the signal that generated the EA,
Start signal DC8TAR of dither counter 10-10
A signal (
TRM) is generated. FIG. 12 shows a detailed configuration of the main scanning counter and decoder 10-12.

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

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

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

A comparator 10-14 compares the up-count output M-ADR of the memory address counter 10-8 with the set value from the controller 10-2. Comparator 1
The controller 1022 controls the memory address counter 10- by the signal MO'VER which is O-140A≦B output.
It is detected that 8 has reached the A input value of Jinpa Lake 10-14. Also, in this state, the MOVER signal is in logic state 1.
(hereinafter referred to as H level), the input to the CL of the memory address counter 10-8 is the NOR gate 1.
0-30 inhibited by memory address counter 10-
The count-up operation of 8 will stop.

Reference numeral 10-15 is a □double back hole, consisting of memories for one line each in memory X and memory Y, and the read and write operations of memory X and memory Y are reversed. Also, switching this buffer is done using BuffCH.
This is done by inputting the G signal, and the REIT 2 address signal,
As write address signals, 0DADR from dither counters 1'0-10 and HADR from main scanning counter decoders 10-12 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 8YNC signal.

Reference numeral 10-17 is a horizontal synchronizing signal generating section which outputs an IBD signal having approximately the same frequency as that of the BD input from the printer via the video interface. If the BD double P-BD specified by the video interface is not input from the printer 10-3, this IBD signal is sent to the selector 5EL5.
By selecting at 10-22, it is used as a BD double R-BD for the main scanning synchronizing signal H8YNC and +7-Goo inside the RMU.

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

10-19 is a selector for writing data to the double buffer memory 10-15. Image signal R-VDA from v-p- and expanded image signal D from expansion circuit 10-6
VDO is selected according to instructions from controller-10-2.

10-20 is an LN-BT double signal selector used as a count start signal for the main scanning quanta decoder 10-12 and as a clock input for the line counter 10-11, and is used as a clock input for the line counter 10-11. -VE double signal controller 10
- Select according to instructions from 2.

10-2114 Select the OVE signal corresponding to the VE from the main scanning counter decoder and the ■E signal 1l-VB from the reader using the vE multiplication signal-VE selector going to the printer according to instructions from the controller 10-2. .

10-22 is a selector for HSYNC as described above, which is selected by 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, and by selecting the AO and BO large inputs, the image signals P-VDA and P-VDB to the printer are connected to both the R and -VDA from the reader. When the printer is connected, the recorded image VD output to the printer becomes a binary image, as is clear from FIG.

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

The other input signal R- of this AND game) 10-34
HALF is a signal from controller 10-2.

If R and -HALF are at H level, the image signal P'-VDB going to the printer is the image signal R-V from the reader.
Recorded image V that becomes the same signal as DB and is output to the printer
D is the image signal R-V from the reader as shown in FIG.
The image is a composite of DA and R-VDB.

If the R, -HA L F signal is in logic state O (hereinafter referred to as IT L level''), the image signal P goes to the printer.
= V D B l-1: Fixed at L level. Therefore, as shown in FIG. 7, the image signal VD output to the printer is recorded on the output paper as the VDA signal with a duty of about 50% for one pixel (one video clock) section. This is H when the R-HA L F signal is at L level.
This means that the lighting time of the laser light emitted from the laser unit 5-4 is about half that of the case of the image signal from the reader by setting the R-HALF signal to the L level. % output image density is obtained.

When A2 manual power and B2 manual power are selected by the video selector 10-23, the image signal P-VDA going to the printer is output from the double buffer memory 10-15 by AND gate 1.
Signal ratio M through 0-27.10-28, U-VD. The image signal P-VDB still going to the printer is the signal RM.
A signal is sent from the U-VD through the KAND gates 10-32. The other input R, MU-HALF of this AND game) 10-23 is a signal from the controller 10-2, and if this RMU-HALF signal is at the ■(level), the image signal 1"VDB going to the printer is The recorded image VD, which becomes the same signal as P-VDA and is output to the printer, is the seventh
As can be seen from the figure, a binary image is created by the image signal RMU-VD. If the RMU-HALF signal is at L level, the image signal P-VDB going to the printer is fixed at L level. In other words, the P-VDA has double buffer memory 10
The image signal RMU-VD from -15 is transmitted, but P
-VDB remains at L level, so the image signal VD output to the printer is 1 pixel (
The image signal is recorded on the output paper as an image signal with a duty of about 50% for one video clock section. This is RMU-
When the HALF signal is at L level, it means that the ON time of the laser light emitted from the laser unit 5-4 is approximately half that of when it is at H level.
By setting the F signal to L level, an output image density of about 50% can be obtained.

When A3 manual power and 83 manual power are selected by the video selector 10-23, the image signals P-VDA and P-VDB going to the printer are transferred from 'J-Goo to (D Image signal R-VDA, R-VDB
and image signal RM from double buffer memory 10-15
It is a composite of U-VD. Here, the aforementioned R-HA
Table 1 shows the image signal VD output to the printer by arbitrarily combining the LF signal, R, and MU-HALF signals.
become that way.

10-25 is the Buff from the EOL detection circuit 1o-7
This is a three-man power AND gate that gates the LN-sT times signal in response to the CHG ENB signal (double buffer switching permission) and generates the switching signal Buff CHG♀ for the double buffer memories 10-15 and the write buffer.

Reference numeral 10-35 is an expansion error counter that counts the number of lines with expansion errors caused by the 1°-6 expansion circuit.

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

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

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

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

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

Hereinafter, specific operations will be explained in order.

(1) Binary compression function The image signal input from the reader is transmitted as a VE multiplied signal synchronization signal representing one main scanning line as shown in FIG. A sub-scanning section corresponding to one page is expressed by the VSYNC signal. ①E times signal In FIG. 10, the R-VE times signal is expressed.

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

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

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

Image signal R-VDA sent from reader 10-1
Clock 0 used inside R and MU to compress
Clock R-VC from reader 10-1 as 8YS
Set 10=18SEL1 to select LK.

Image signal R-VDAf input from reader 10-1
The data is stored line by line in the D-48 double buffer 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, 1.0-19SEL
Set 2.

Next, a synchronization signal LN-8T for each line is set, and 10-20SEL3 is set to use the R-VE multiplied signal from the reader 10-1. Also, leader 1
0-1 is a synchronization signal to generate R, -VE.As mentioned in the explanation of the video interface, the R-BD double signal is required, but this R, -BD double signal can be used to generate a horizontal synchronization signal. 10-22SEL5 is set to output the IBD signal from section 10-17.

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 corresponding to the main scanning direction margin of 7Qmm up to the area B in FIG. 13 from 4677. The trench comparator 14-5 has 140 m during main scanning of area B.
The value 1371 is set by further subtracting 2204 bits corresponding to m minutes 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 has 46
Set 77.

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

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

Both HADR and R-VE times the rising edge of the signal.4677
There will be a countdown from.

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 V-DEC given to the EOL detection circuit 10-7 is at L level, the DR
PI signal doubling, P2 signal has L level, Buff
When the CHG ENB signal and the DataENB signal are at H level, the expansion circuit 10-6°EOL detection circuit 10-7
It is configured so as not to affect the compression operation.

Furthermore, the writing start address to the compressed image memo IJ 10-5 is set in the memory address counter 1o-8.

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

The line counter 10-11 counts down by the LN-8'r signal. That is, when the main scanning section signal R-VB from the reader is input 1574 times, the line counter 10-11 sends the count up signal to the controller 10.
-2, the controller detects that the image signal from the reader has entered area B. Thereby, the controller should cause the compression circuit 10-4 to start compressing the image (
'While changing V-ENC from L level to H level,
In order to measure the sub-scanning length of 210 mm in area B, 3307, which corresponds to 210 mm, is placed on the line counter 10-11.
Set.

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

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

This situation is shown in FIG. R-VD in Figure 14
Part A shows an example of inputting an image signal of one line, in which 2 bits of white, 2204 bits of black, and 5 bits of white are input as image signals in the trimming area of a certain line. With this RLVDA input, a 5-byte running code is generated in the compression circuit 1°]4. That is, the first white 2 creates a 2H T code, then the black 2204 creates an M code 91H, the T code 15H9, the last white 5 creates a 5H T code, and then GH-AR, E
An EOL code is generated at the end of A, and the compression circuit 1o
The data is written into the compressed image memory 10-5 by the write request DWP pulse from -4.

A remote address counter 10-8 (which addresses the compressed image memory 10-5) is counted up by a signal from which the DWP pulse passes through gates 1o-29 and 10-30.

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

In FIG. 15, a compressed image S (end address 8B) and a compressed image T (start address TS) are stored in the compressed image memory.
) is stored, address SE and address 18.
When writing the compressed image U between 0 and 0, the controller 10-
2 is a memory address counter 10-8 which calculates the write start address US based on the end address SE of the compressed image S.
, and the start address TS of the compressed image T is set in the comparator 10-14 as an address limiter. When the write progresses and the count output of the address counter 10-8 reaches the TS value of the comparator 10-14, the comparator outputs A≦B, and a new write request pulse 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. In addition, the controller 10-2 receives 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 could not be written is set as an empty area, and the image is moved from the memory. output is prohibited and a message to that effect is displayed on the reader display section.

The controller 10-2 performs MOV e at the end of image compression.
If the r signal is determined and it is detected that the MOver signal is not generated, it is determined that the image compression writing has been successful, and the address output MADR from the memory address counter 10-8 is read and the currently written compressed image is It is retained in the controller's internal memory as the end address and used to set the start address for writing the next compressed image.

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

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

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

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

In FIG. 16, the dithered image signal is (16-
1) is input from the reader 10-1. In this embodiment, an 8.times.8 dither matrix is used for each block, the details of which are shown in (16-2) block a in FIG.

Suppose that the image signals read from the reader are uniformly divided into 3
If it is a 2-level signal, a black signal is output where the threshold value of the dither matrix is 32 or more, and (16-
An image as schematically shown in (16-1) is obtained using the dither matrix of 2).

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

Here, the main scanning line signal indicated by H is R of (16-4)
The signal becomes a VDA signal, and state changes occur eight times in four blocks. The number of state changes is proportional to the number of blocks, and for an A4 sheet with a width of 297 mm, 1168 state changes occur.With silan length encoding, 1170
The amount of encoded data is in bytes. This 1170
A byte is approximately twice the amount of data as the original image amount of 4677 bits, which often results in an increase in the amount of image information.

-The image signals obtained from the H lines of t and te (16-2) are extracted between 4 blocks by extracting the image signals processed with the same threshold value as shown in (16-3) and rearranging them in block order. , (16-4), the state changes twice. Like Suzuwachi (1,6-3),
Signals based on the same threshold value for each block have little variation in black or white status, so arranging these signals consecutively increases the continuity of the image.

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

The dithered image signal RVDA from the readers is written to 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.
It gets sucked in.

In this embodiment, since the main scanning of the dither pattern is repeated at 8-pit intervals, the dither counter 10-10 counts down to 8-pit 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. Also, the controller 10-2 is (16-1)
Based on the main scanning compression block number N shown in , the value obtained by subtracting N-1 from the counter setting value of 13-2 is calculated by the comparator 13-2.
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-AREA signal bit length), which is 2N×8.

When the Dither signal in FIG. 11 reaches the H level, the 3-bit counter 13-1 and the 10-bit counter 13
-2 is separated, and the counter '13-2 counts down and the number of blocks N is set in the comparator 13-3.
□ A of comparator 13-3 =
When the B output is generated, the counter 13-2 is reloaded to the initial set value, and the counter 13-1 runs by 1.

That is, the counter 13-2 counts the number of blocks N, and the counter 13-1 specifies which threshold value in each block the image signal is based on. In this way, the main scanning direction of the dither matrix.

It is possible to select an arbitrary lock length N by the comparator 13-3, and it is possible to cope with 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 the trimming and moving processes are not performed and the compressed image signal from area B in Fig. 13 is compressed image memo IJ 10 using binary image compression. For example, assume that the compressed image is stored 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 end in the sub-scanning direction, prior to the image expansion □ force in the B range. That is, in FIG. 4, pre-7' is the distance from the transfer position of the photosensitive drum to the laser-exposed point a1, and
Since the distance from b to the registration paper feed point C' is configured to be equal, A3 paper can be printed with 4-7 registration rollers.
After feeding the output paper by 100 mm in the sub-scanning direction, the stretching operation is started and the 8 images shown in FIG. 13 are output. Therefore, after outputting the registration paper feed signal VSY'NC to the printer, the controller 10-2 sets the number of lines corresponding to 100 mm in the line counters 10-11. This value is 1574 at a resolution of 400 dpi'.
It becomes a line.

'Line synchronization signal L'N'-8T during image expansion is 10-
BD double copy P-BD from the printer is selected by 5EL3 of 20 and 5BL5 of 10-22. Further, the internal clock 08YS is synchronized with the internal clock generator 10-16 in synchronization with H8YNC selected by 5EL5 of 10-22.
Select the I-CLK generated by 5EL1 of 10-18.

Now, when the aforementioned line counter 10-' 11 finishes counting 1574 lines corresponding to the sub-scanning margin of 100 mm, the controller outputs the image expansion signal V-D E C
is output and the decompression operation of area B is started, but before that, the memory address counter 10-8 is
The final MA"DR value at the time of compression is set in the comparator 10-14.

The decompression circuit 10-6 decompresses the image line by line according to the VD and E-C signals from the controller 10-2, and the decompressed image signal DVDO is sent to the double buffer memory 10-2.
15 and output to the printer one line later. At this time, the dither counter 10-10 functions as a write address counter for the double buffer memory 10-15, and the main scanning counter decoder functions as a read address counter.

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

A is set in the comparator 14-2. A-4676 for comparator 14-3, A for comparator 14-4, A-2203 for comparator 14-5, B for comparator 14-6, and B- for comparator 14-7.
A is set in the comparator 14-8 so that when the 2203° counter 14-1 reaches A, the dither counters 11-1 and 13-2 start operating. Also, dither counter 1
3-1.13-2 sets A as the load value so that it performs 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 10-12
HA D R, counts down from A+LMG,
The LMG counts the clock, and when HADR becomes A, the OVE signal, the AREA signal, and the DC8TART signal are generated.

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

After HADR reaches A, when HADR reaches B by counting 1102 clocks, which corresponds to the 7Qmm margin in the area B in FIG. When the output image signal becomes valid by Game) 10-27 and HA D R reaches B-22, 03, 2204 pixels corresponding to 140 mm during main scanning of area B are output to the printer. , T
The RM signal goes to the L level, and the subsequent image signals going to the printer are invalidated by the gate 10-27. How is the decompressed image signal stored in the double buffer memory outputted to the printer?
The writing of the expanded image DVD to 15 is as follows.

Simultaneously with the rise of OVE, the H-AREA signal applied to the decompression circuit 10-6°BOL detection circuit 10-7 becomes H level, and the decompression circuit 10-6 starts decompression of the compressed image MR and code.

The decompression circuit 10-6 reads the compressed image MR code from the sub-scanning decompression section signal V-DEC, the main-scanning decompression period signal H-All, and the section compressed image memo +710-5 in which EA is at H level, and sends the code to a decoding counter (not shown). Intake,
15Ys It counts down by the clock and generates an expanded image DVD. That is, as shown in FIG. 17, the T code 2H of the MR code is taken in and 96sys 2
Outputs a DVD of the clock white signal. I'SYS
2 clocks, the decode counter counts up, generates the compressed image request signal DRP1, reads the next MR code from the compressed image memory 10-5, and then outputs the DVD.
Inverts the output of O.

The next input MR code is 91H, which is an M code, so count the 9'SYS clock by 2176 clocks and D.
Generate RPI. However, since the M code and T code are a pair, the DVD is not inverted at this point, but is inverted by the count up of the next T code 15H. In this way, the image is expanded and lengthened during the period in which HAREA is at H level, and the dither counter 10-10 calculates 0DAD.
The expanded image DVDDO is written into the double buffer memory 10-15 by R. 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. Furthermore, since the dither counter shown in FIG. 11 performs binary expansion, l) the i ther signal is set to L level.

Comparators 14-4 and 14-5 are set so that the length of the HAREA signal during image expansion is the same as the H-AR and EA used when compressing the image of area B, and the number of locks is output. When the HAREA signal falls, the EOL detection circuit 1o-7 determines whether the extension operation of the current line is successful or unsuccessful.

The success of the decompression operation is determined by the fall of the MAR and EA double signals, the fact that the next MR code is EOL, and at that point the decode counter of the decompression circuit 10-6 counts up and the DRPI signal is generated. This is done when the three states of being and are present. This is because the code may contain an error when writing the MW code signal from the compression circuit to the compressed image memo IJ10-5 or when reading the MR code from the compressed image memory. If there is, accurate interval signal HAR from outside
DRP is the end of EA and the end of one code decompression operation.
This is because the generation of the I pulse and the line end code EOL do not match. Then, it is determined that the above three conditions match and there is no decompression error, and the EOL detection circuit 10-
7 generates DRP2 to read the MR code at the beginning of the next line for the next line.

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

In FIG. 18, the line synchronization signal PBD 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 Buff CHG signal for switching the double buffer memory is always generated. Further, the Data BNB signal is at the L level at this time, and the image signal RMU-VD output to the printer is kept at the L level by the A N and D gates 10-28.

The controller 10-2 uses V-DEC to perform image expansion.
Set the signal to H level and perform the following 1(1(, EA1', HA
REA 2. . . . The line-by-line image expansion operation is performed in the order of HAREA 9. HA when decompressing the image
The REA area is divided into three states. In other words, honor δ
The X state in which the decompression operation is performed, the y state in which the decompression error is eliminated, and the decompression error 1 state 2 in which DECENB from the EOL detection circuit is at L level.

■-'DE'C signal becomes Hv level;
Image decompression is started from AREA4 in the decompression circuit 10-6. As shown in Figure 18, the first f('AREA
An decompression error occurred in 1 (state y), and EOL
The detection circuit 10-7 is connected to Bu f f at the rear end of HAREAL.
The CHG'EN'B signal and the DECENi signal are set to L level, and in the next line HAREA2, the double batter memory is switched and the expansion operation of the expansion circuit 10-6 is stopped, and EOL detection processing for the expansion error recovery device is performed. (state 2).

' The EOL detection circuit 10-7 is an expansion error detector.
HAREA is H section MR, code is EOL
The DRP2 signal is repeatedly generated until code FFH is detected. By detecting the EOL code, the synchronization between the compressed image data and the HAREA signal is restored, and the leading MR code for image expansion in the next HA R, EA 3 is read out.1. DECENB is returned to H level and the extension error recovery operation is completed.

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

HAREA4. Since the image expansion operation has completed normally on both lines of HAREA5, Buff CHG E
The NB signal remains at H level, but in HAREA6, an expansion error has occurred as in HAl'tEA1.

Due to this state, the EOL detection circuit 9 sends the Boff CHG ENB signal in HAREA 6 so that the decompressed image data containing the decompression error written in memory Y of the double bass sofa memory will not be output to the printer. H.A.
It is set to L level at the rear end of REA6, and switching of the double buffer memory is prohibited until image decompression is successfully performed in HA REA8. In the meantime, between the section where error recovery is being performed in HA RE A7 and the section where the next decompression operation is being performed in HAREA8, the image data of the decompression effect decompressed in HA and REA5 is repeatedly sent to the printer R and MU. -Output as VD signal.

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

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

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

The controller 10-2 has an expansion error counter 10-2.
At step 35, the LNST signals generated while the Buff CHG ENB signal is at L level are counted, and the total number of lines in which an expansion error has occurred and lines in which error recovery has been performed is counted. This count value represents the number of lines for which expansion 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
Processes such as setting the E'C signal to L level and stopping the expansion operation are performed. As a result, decompression errors are detected without waiting for one page of images to be decompressed, so that decompression errors can be quickly processed.

During expansion, the sub-scanning expansion section signal V-DEC output by the controller 10-2 is set to the same number of lines as when outputting the V-ENC signal during compression to the line counter 1. O-1
1, count and output.

Therefore, if no decompression error occurs during image decompression, the controller 10-2 controls the line counter 10-11.
VDEC upon receiving the predetermined sub-scanning line count completion output from
At the timing of returning the DEC signal to the bell, the address output M-ADR from the memory address counter 1°-8 becomes the same as the final M-ADR value when the decompressed image is compressed.

Comparator 1t)-14 contains the final M-N during compression.
Since the DR value has been set, the controller 10-2 should detect the % MOVER signal when the VDECDEC signal goes to bell.

By the way, if an expansion error occurs as described above during the expansion operation, the EOL detection circuit 10-7 must reverse the EOL code (to skip the MR code, when the MOVER signal is generated) to recover from the expansion error. , a remaining count is generated in the line counter 10-11.In order to count all the remaining counts, the V-DEC
Even if the signal continues to be output, the memory address counter 1°-8 has already stopped counting due to 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 will be repeatedly expanded. This will be taken into the circuit 10-6, and all remaining lines will become extended error lines.

Therefore, in order to prevent this situation, controller 10-
2, while setting the VT)EC signal to H level and waiting for the count up from the line counters 10-11, the %M
Check the OVER signal periodically, and when V-DEC is at H level, M. When VER is detected, the V-DEC signal is immediately set to the L level to stop the image expansion operation and to avoid counting unnecessary expansion error lines.

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

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

Figure 19 shows a point t of H1 bits in the main scanning direction and ■1 line in the sub-scanning direction from point S1 of an expanded image U of A4 size.
This is an example in which an image T having a main scanning size of H2 bits and a sub-scanning size of V2 bits is trimmed using 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 expansion operation for one line starts when the HADR from the main scanning address counter/decoder 10-12 reaches 4677, although it is started using the LN-8T signal by the D signal as a synchronizing signal. That is, 4677 is set in the comparator 14-4 so that HADR is 4677 and H-AREA is at H level. Also, A4
The comparator 14-5 is set to O so that the expansion ends at a width of 4677 bits, and the length of HAREA is set to 4.
It is assumed to be 677 bits. In addition, 4677 is set in the comparator 14-8 that creates the output timing of the DC5TART signal so that the DADJ that writes the expanded image signal DVD expanded by the expansion circuit 10-6 into the double buffer memory 10-15 and the HADR that reads it performs the same operation. death,
Dither counter 10-10 counter 13-1.13-
The LD value of 2 is also set to 4677. As a result, the image signal compressed by U as described above is expanded as is.

As shown in FIG. 20, the controller 10-2 sends an A4 copy paper registration paper feed signal VSY to the printer 10-3.
At the same time as outputting NC, a sub-scanning expansion section signal V-DEC is outputted. As a result, the image expansion output starts at the same time as the printer paper feeds, and if there is no need to perform trimming here, by outputting the lever, V-DEC over the same time span as PVSYNC, the expansion image of U A4 can be output. Everything is output as is on A4 copy paper. Here, in order to perform the trimming as described above, the controller 10-2
In order to erase the image signal of the ■□ line,
The TRM signal is fixed at L level during the V1 line after outputting the EC signal, and the image signal read from the double buffer memory is fixed at L level at 10-27. For this purpose, by setting 1pppn to the comparator 14-6 that outputs the TRM signal while counting the %V1 line, and setting 4677 (1245H) to the comparator 14-7, the flip-flop 14-12 is only reset. Do it like this.

(2) After counting the 1 line with line counters 10-11, trim the T area of the V2 line during sub-scanning and the H2 bit during main scanning from the tl position. For this purpose, the line counter 10-11 is set to the v2 line, the sub-scanning V2 line is calculated, and the comparator 14-6 is used to generate a TRM signal representing the H2 bit width from point t in the main-scanning trimming area between them.
(4677-Hl) and comparator 14
-7 is set to (4677-(H1+H2)).

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

By setting the constants as described above, trimming of the T area between the point tl and line 2 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 10-11 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 does not need to decompress the compressed image code in the shaded area, and sets the VDEC signal to the L level here to stop the decompression operation. Since the VDEC signal became L level, the EOL detection circuit
The t a E N B signal goes to L level and the subsequent V
The R line is the white signal (L level) for the image signal to the printer.
Thus, the trimming output of the T area is completed. In this way, by not decompressing extra compressed image code, the number of decompression errors is reduced, which reduces the incidence of misprints caused by errors in the decompressed image, and improves copy operations. reliability is improved.

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

In this case, when writing the expanded image into the double buffer memory, the expanded image is moved by one line, and when the moved image is read out from the double buffer memory, the desired T portion is trimmed. All movement and trimming of this expanded image is performed using HADR as a reference. That is, in FIG. 21(a), the part T expanded by the expansion circuit 10-6 in the address range from HADR (4677-H,) to HADR, (4678-(H, 10H2)) is D.A.D.
The write to the double buffer memory is interrupted by R, and in FIG. 21(b), the write from the double buffer memory to HAT)R
When read by H3-IT, bits are moved from HAD R (4677-H3) to HAD
It is often read in the range of R (4678-(H20H3)). This image movement is executed by the address control of DADR, and when the portion T of the decompressed image is written to the double buffer memory in FIG. 21(a) (HADR
H3-H□
All you have to do is write to the address of 4677-H3 that has been moved by DADR. In other words, as is clear from FIG. 21(a), the DADR count start value at HADR=4677 is calculated as 46 by the number of main scanning movement bits I]3-H1.
77-(H3Hl). This H3 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
Although the TR and M signals are trimmed by the RM signal, as shown in FIG. 21(b), the HADR is changed from 4677-H3 to 4678-(H2
+H3), the comparator 14-6 is set to 4677-H3, and the comparator 14-7 is set to 4677-(H2+H3).

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 tI point of the trimmed image is recorded at line v3 from the edge of the paper. This is an example.

The deviation in the sub-scanning direction between the copy paper and the expanded image U is V2
-V, line, so the controller 10-2 is
After outputting the copy paper registration paper feed signal P-VSYNC to the printer 10-3, the line counter 10-
After counting V3-V1 lines in step 11, the sub-scanning expansion section signal VDEC is set to H level, and the expansion operation of the expanded image U is started. Here, the image in the T area is output using the TR and M signals when one additional line has elapsed since the V-DEC signal was set to the I] level. Then, when the line counter counts the v2 line for the sub-scanning of the T area, the -DEC signal is set to L level, and the expansion operation is ended.

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

In FIG. 22(C), before outputting the registration paper feed signal PVSYNC to the printer, it is necessary to perform image expansion for three lines (1) to (2) in advance. Therefore, the controller 10-2 uses the line counter 10-11 to
□ After decompressing the image for -73247 minutes, -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-I) EC signal is set to H level again to continue the interrupted image expansion operation, and vl-73
247 minutes of image movement is performed.

Trimming of the T area is as described above, but if point P protrudes beyond the v3 line from the edge of the paper, the T area output on the copy paper will not be the same. 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. That is, when an image decompressed by the RMU and an image from the reader are overlaid and output to a printer, a common VSYNC signal must be used in order to accurately match the overlay position of the two images. However, VSYN from RMU to leader
Since there is no way to signal C, PVSYNC
oVsYNc (RVSYNC) must be used from Goo. Reader and asynchronous controller 10-
2, it is difficult to determine the exact timing of when RVSYNC is input. The controller 16-2 then receives the VSYNC (R, V
Sufficiently before inputting the SYNC), locate the beginning of the MR and code of the decompressed image that will be output on the copy paper after decompression of the 1-v3 line image from the compressed image memory.
The decompression operation must be started again in accordance with R and VSYNC. In other words, 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, there is no need to synchronize reader C, and 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, the PVSYNC signal is immediately output without once lowering the DEC 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 1o-1 at the time of dither compression
If the main scanning image is rearranged by .o and expanded as it is, the output copy 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 dithered images from the original reader are rearranged in the order of the images.

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). The Dither signal of the counter is set to H level, and the counters 13-1 and 13-2 are operated in the same way as in the case of dither compression.

In this case, the counter load value set by the controller 10-2 in the counter 13-1. The load value of the counter must be the same value 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. The size comparator 13-3 is set to a value obtained by subtracting (N-1) from the load value of the counter 13-2 using the number N of blocks used during dither compression processing.

In the configuration of this system explained above, the leader, R,
Detailed procedures for serial communication between MUs and between RMU and printer and image processing operations will be described below. The program shown in the flowchart used in the following explanation is
The data is stored in advance in the memory ROM of the microcomputer that constitutes the control unit of the printer, printer, R, and MU, and is controlled by reading this as appropriate.

The serial communication shown in Figure 6 is DEvxcg in Figure 8.
Connect+Dgvtca POWER Ready
.

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

FIG. 23 shows processing for RMU commands.

The RMU receives commands from the reader. This command is the RMU mode instruction command, RMU memory instruction command, and RMU
) Rimming instruction 1 command F, RMU) Rimming instruction 2
command.

RMU) Rimming instruction 3 command, RMU) Rimming instruction 4 command, R, MU) Rimming instruction 5: +v
)', RMU)! 6 Jming instruction commands (These 8 commands are collectively referred to as RMU instruction commands.)
If it is either (S-1, 00-1,), the later-described tenth metal body status for each command byte is returned to the reader (S-100-5). R,
If the input command is not one of the RMU instruction commands, the MU determines whether it is the printer start command listed in Table 1 100-1 described later (S-100-2).
.

If an FtMU is connected to the system, the printer start command is output from the reader after the RMU instruction command is output from the reader, so the RMU mode described below has already been determined at this point. If this RMU mode is the "input mode" described later, the printer does not perform a copy operation, so the RMU does not output this printer start command to the printer, but outputs the overall status shown in Table 10 to the reader (S- 100-3, S-1
00-5). In addition, for commands that include information necessary for the operation of the RMU, such as the paper size instruction command, the contents of the command are memorized and then output to the printer (S-100-4
).

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

When the RMU inputs the status from the printer, it determines which command this status corresponds to, and
It is checked whether the application status in Table 15 corresponds to the application status request command in Table 108-7 (8-101-.1).

If the input status is an application status, after adding RMU connection information (S-101-
2L Output to reader as application status.

Similarly, it is determined whether the status from the printer is the error occurrence unit status in Table 11 (
S-101-3), if the compression failure flag described below is set, return the error unit status with compression failure information (RMU memory overflow) to the reader, and if the compression failure flag is reset. In this case, the error unit status from the printer is returned 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, 8-101-9), 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 processes it. , transfer is repeated 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 shown in FIGS. 23 and 24 below.

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

Table 1 shows execution commands that prompt 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.

1'0O-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. Paper sizes such as A4-JB5-R are encoded and stored. Reference numeral 100-6 is a number of copies instruction command, and in the second byte of this command, 6 bits from bit 1 to bit 6 can be used to set the number of copies per copy up to 64 copies. 100-7 is a 3MU mode instruction command which is one of the R, MU instruction commands, and information on the R, MU mode is stored in the second byte as shown in Table 5. 100-8 is R that specifies the memory area of the RMU.
, MU memory instruction command stores the contents of the memory area specified in the second byte (Table 6), and only one bit of the corresponding memory area is set (``'1''). 10
0-9, 100-10, 100-11.

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

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

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

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

By collecting these statuses, the leader can know the cause of the error occurrence in the entire system, making system management easier.

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

The league obtains RMU connection information from the application status in Table 15, which is the output of the application status request command 108-7 in Table 9 (S-10
2-1). In addition, the paper in the upper and lower cassettes of the printer is determined by the cassette paper size status in Table 14 by outputting the lower cassette paper size request command 1'08-5 in Table 9 and the upper cassette paper size request command 108-6 in Table 9. Obtain size information (S-102-2). After this, 108-1 overall status request command in Table 9 10 in Table 9
Obtain information on whether there is an error in the printer, R, or MU based on the overall status in Table 10 and the error unit status in Table 11 by outputting the error unit status request command in 8-2 (S-102-3, 8) −
102-4). After this, it is checked whether there is an error (8-102-5). If there is an error at this time, Table 108-3 Operator call error status request command, Table 10
8-4 Output the service call error status request command and obtain detailed error information from each status input (S-102-6, S-102-7)
It is possible to notify the operator of necessary information, such as a paper shortage or an RMU memory overflow.

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

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

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

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

Setting the dither counter, main scanning counter, etc. (C-■
). II (, MU mode is “memory input mode”
In this case, the RMU does not send a printer start command to the printer, so the printer does not output an output paper ready signal (hereinafter abbreviated as PREQ) to the RMU, so R and MU read PR and EQ instead of the printer. Output to (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 PRBQ to the reader. and output it (B-■). When the reader inputs PREQ from the RMU (from the printer), it outputs a corresponding output paper feed signal (hereinafter abbreviated as pH and INT).
is output to the RMU. (B-■).

When the RMU mode is in memory input mode, PRINT is not output to the printer (D-■) It is as if the printer inputs PRINT and outputs an image request signal (hereinafter referred to as VSRBQ) in response. The RMU outputs VSRBQ to the reader (B-■).

When the reader inputs VS and REQ from the RMU, it outputs 5YNC (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, I(, MU memory overflow, etc.) (B-[phase]). Since the number of copies is managed by the reader, when a printer stop command is input from the reader, the RMU performs a mode reset (C-■) and the copying ends.

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

The first is a mode called "memory bus mode", in which the RMU outputs two image signals RvDA and RVIDB representing three values input from the reader 10-1 as they are to the printer 10-3. The reader 10-1 and printer 10-3 operate as if they were directly connected. Therefore, in this mode, the RMU outputs the signals input from the readers 0-1 through the video interface to the printer 10-3 as they are, and
The signal input from the reader 10-1 is output as is to the reader 10-1. - The second mode is called "memory high speed mode", and the RMU receives image signals R and V from the reader 10-1.
D'A is compressed and stored in a compressed image memory, and then the compressed image data is continuously read out and output to a printer.

In other words, the rider 10-1 requires mechanical reciprocating motion.
Copying by scanning the original is only required once, and subsequent copies do not require mechanical reciprocating movement.
By repeatedly decompressing and outputting the compressed image data stored in the compressed image memory of the printer 10-3 to the printer 10-3, high-speed processing of large-volume copies becomes possible.

The third mode is called "memory input mode," which allows the RM to be input without operating the printer 10-3.
U compresses the image signal input from the reader 10-1 and stores it in a compressed image memory.

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

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

“Memory High Speed Mode” has three modes inside RMu: “Retension and Mode”, and “Output Mode”.
, “through-out mode”. "Retention mode 1" is the first sheet of "Memory High Speed" that compresses the image information (signal) from the document in memory and passes it through to the printer. success.

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

If the failure information (RMU memory overflow) can be obtained and the compression to memory is successful, the next copy (
Image formation (from the second image onward) is performed using the expanded image from the memory.
The league will stop scanning manuscripts because they can be copied (copied). The RMU resets the selector so that the memory can be expanded from the next copy. For example, the video selector 10-23 in FIG. 10 is reset to output the decompressed image from the RMU's memory to the printer.

The mode in which the selector is reset in this way is called the ``output mode.'' Conversely, if compression to memory fails, leaving the ``retention mode'' allows the image to 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-out mode 1" is "Memory pass mode M: The selector settings in RMU are the same, but the image information from the league is a binary image with the same values of threshold generators A and H. On the other hand, the latter is a ternary image with independent vDA and VDB, so the name has been changed. Due to this change in the RMU internal mode, the RMU will "output a binary image regardless of whether image compression to the memory is successful or unsuccessful in Memory High Speed 1, eliminating the difference between the first image and the second and subsequent images. Table 18 shows the correspondence between RMU mode and RMU internal mode.

The league operation will be explained using the 70 chart shown in FIG.

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

The league outputs the printer start command (S-103-4), performs the initial settings necessary for the copy operation, and then sends the RMU
After inputting IR and EQ from (S-103-10),
Output PRINT to RMU (S-103-1'
O). Furthermore, start the timer (S-103-11
, ), wait for a certain period of time until this timer out, 9-
103-1. '2) When the RMU internal mode is "output mode", the optical system is not started (s-L
t, oa-14,), counts down the number of sheets, checks whether the number is 0 (S-103-20), and outputs a printer stop command if it is 0 (S-10
3-21).

When the RMU internal mode is “other than output mode 1,” scan the optical system (S-103-15
), starts reading the original, and (S-103-16) outputs the image to the RMU. After checking the completion of reading (S-103-17), if it is in memory input mode, the number of sheets is not checked (reading of only one original is accepted). A printer stop command is output to the RMU (S-103-21).

゛'Memory input mode 1. In cases other than 'output mode', count down the number of sheets and press (S-10
3-19) When the number of sheets is 0, a printer stop command is output, and when it is not 0, the PREQ input is set to an input state and the above operation is repeated until the number of sheets becomes 0.

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

When the printer receives a printer start command from the league side (including the RMU) (S-104-1), it starts various electrical operations such as drum charging (S-104-2). When the printer is ready to feed paper (S-104-3)
, output PREQ to the league side (S-104-4),
If IRI'NT is input from the league side in response to PREQ (s-1, o4-s), paper feed (S-1, 05-
Do 6).

When paper is fed and images can be received (S-104-7),
VSREQ')-Dahe IB force (S-104-8)
. In response to VSREQ, the reader outputs VSYNC and outputs an image signal (s-104-9).

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-104-12). If you repeat the above operation for one copy, the league will output a printer stop message, so please check whether the printer stop message has been received.S-104-1
3) Upon receiving this, the printer stops each part of the printer (S-104-14).

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

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

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

FIG. 28(1) shows a state in which no image is written to the RMU. At this time, MS←0. M.E.
, MLMT is set. This also indicates the maximum free space available in memory. When memory A is selected by the RMU memory instruction command and an A4 size copy is performed in dither memory high speed mode, the RMU determines in which RMU mode the image stored in memory A was compressed, as shown in (2). Information (MA-VI
DEO), compressed image original size (MA-PSZ)
, reader read mode (MA-MBTHOD), memory A image write start address (MAS), and 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 the state in which memory B and memory C are written in the state (2). Memo IJ in state (2)
When writing to memory B or memory C is instructed, the area ■ in state (2), which is the maximum empty area, is MS 4-MAE
+1, set as ME 4-M'LMT. At this time, if memory A is specified again, the area including the empty area above and below memo IJ A is created as a new MS←O, MB4-MLM.
Set as 'l'.By setting in this way, it is the same as when memory A is specified in state (1), and the memory can be used effectively.If memory A is specified in state (3), In the state (3), the memo IJ
There is no continuous free space in A, and the amount of memory in A and (
Compare the memory amounts of the empty area (3) in the state of 3), and select the one with the larger memory amount as the new memory area A. (3)
In the state of , the empty area ■ is larger, so M'84
-MBE+1, ME←MLMT is set, and the old memory A area is set as an empty area.

The state (4) is the state in which image information has been written in the empty area (3) in the state (3). If there is a write instruction to memory B in this state, memory B in state (4)
There is no continuous empty area in the area, and the area with the largest memory amount among the memo IJ B area, empty area (2), and empty area (2) is set as the new memory B area. At this time, if the empty area ■ has the largest amount of memory, M8←O, MB4-
MC8-1 is set, and the old memory B 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 states (5) and (6), memory A
.

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

In this way, the maximum number of empty areas generated is the same as the number of areas that can be specified by memory. MAS the amount of memory for this empty space
, M.B.S., M.C.S., M.A.E.

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

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

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

[For explanation of the "retention mode" of the 14MU mode, as shown in FIG. 13, with reference to the flowchart in FIG. m
, 140m from the point after 100mrTl in the sub-scanning direction
An example will be explained in which the image information B of m×210 mm is trimmed and output. The RMU inputs Table 20 as the second byte of the RMU mode instruction command. Bit 6 and bit 5 are used to set the output density of the reader image and RMU expanded image to approximately 50%, respectively, and both are set to ll111, and the RMU mode is set as bit 104-2 in Table 5. 4. Bit 3. Bit 2. Bit 1 is set. Memory A is specified as the memory instruction, and the second memory is specified as the R, MU memory instruction command.
1 Enter the table. RMU) Main scanning compression start position Hp (70
mm), RMU) Sub-scan compression start position Vp (100 mm) as trimming data of rimming instruction command 2
, RMU) Hw (140 mm) during main scanning compression is set as the trimming data of rimming instruction command 3, and Vw (210 mm) during sub-scanning compression is set as the trimming data of rimming instruction command 4, which is output from the reader in millimeter units. (S-1,06
-A-1).

The controller 10-2 converts the position information from the reader into bit units/line units, Hp=1102 bits, Vp=1574 lines, Hw=2204 bits, V
Compressed image position/size information corresponding to the w=3307 line shown in FIG. 13 is obtained.

Depending on the designated RMU mode, selector 5 in FIG.
ELL (10-18), 5EL2 (10-19),
5EL3 (10-20), SEL, 4 (10-21).

5EL5 (1,0-22), video selector (10-2)
3) are R-VCLK, R-VDA, and R-VE, respectively.

Select R-VB, P-BD, AO, BO (7) input.

In order to binary-compress the image signal of the reader and store it in the compressed image memory, the dither signal shown in FIG. 11 is varnished at L level. R.M.U.
Since the mode is "Memory High Speed Bee)-E-)"' (RMU internal mode is "retention mode °), it receives the printer start command output by the reader and passes it directly 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
-106-A-6). At this point, the first memory high speed beat mode is being executed (S-106-
A-7), input a paper size instruction command from the reader to specify the output paper size. S-106-A-8,),
It is stored and held in the MA-PSZ mentioned above. Based on the specified output paper size, settings for various counters described below are performed. First, the aforementioned MS (compressed image write start address) and ME (maximum compressed image write address) settings are set using the memory address counter 10-8 and the comparator 10-.
It will be held on the 14th. The down counter 13-1 of the dither counter shown in Figure 11 has the top 10 of I245H (4677).
Bit 248H (584) is also the down counter 1
The lower three bits 5H (5) are set in 3-2. Similarly, in the main scanning counter decoder shown in FIG. 12, 1245H (4677) is set in the down counter 14-1. Note that comparators 14-2 and 14-3 are used only during decompression, so no settings are made;
-5 comparator is D F 7 H (
3575) and Hp, Hw, 55BH (
1371) and operate DADR at the same time as HAI)R, comparator 14-8 has 1245H
(4677) settings.

When the RMU receives the PRIN'r signal from the reader (S
-106-A-10), output to printer (S-10
6-A-12). When the VSREQ signal is input from the printer (S-106-A-13), it is output to the reader (S-106-A-13).
-103-A-14).

At this point, the RMU mode is ``Memory high speed mode'', since this is the first memory, RMU internal mode.
Retention mode branching (S-106-A-1
8). Then, in Figure 30, VSYN from the leader
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 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 (5-106-F-5).

During sub-scanning of area B in Figure 13, select Vw3307 to the line counter (S-106-F-6>. According to the settings of the selector mentioned above, the image from the reader is passed directly to the printer until the end of the 10-11 line counter. Write the compressed image code from the compressed 99° circuit 10-4 to the compressed image memo IJ 10-5 (
S-106-F-7, 8-106-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-BN
If the C signal is turned off (S-106-F-9), and the VSYNC off state from the reader is input (S-106-
F-10), turn off VSYNC to the printer (S-
106-F-11).

After this, in order to determine whether writing to the compressed image memory has succeeded or failed, move the image using the procedure shown in FIG.
Check the R signal S-106-C-1), MOVE
If the R signal is at H level, writing to the memory is determined to be a failure and the compression failure flag is set (S-106-C
-2)' L. Information about compression failure (RMU memory overflow) can be transmitted to the reader through serial communication during the aforementioned copy operation. With this information, the leader can
It is determined that the retention operation using the compression memory is at the bottom, and image output by scanning the original is repeated for the second and subsequent sheets, and the copying operation is completed. 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 R, MU makes the memory area where the compressed image was being written an empty area, and changes the RMU internal mode to the "through-out mode" by the □compression failure flag. “Through-out 4%-do is the same as pawn need...”, and the V-EN”C signal is the leader's VSY
On (from L level to H level) and off (from L level to H level) corresponding to NC
Since there is no operation to change from H level to L level, RMU
does not perform the compression operation, and the selector is 11)) Careful... Settings and operations VS from the leader
When YNC is input, output VSYNC to the printer (Figure 33, S-106-D-1, 8-106-D-2),
Pass image from reader directly to printer S-106-
D-3), it may wait for VSYNC from the reader.

(S-106-D-4), if VSYNC is input, send cDVsYNc to the printer at t7L (S-106-D-4).
-5) When the reader 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 (
8-106-C-4, 8-106-C-5). Figure 10 5ELL, 5EL2.8EIL3゜5EL4.5EL
5. Video selectors are I-CLK and DVDO, respectively.
, P-BD, OVE.

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

The MA-PS mentioned above is used to set the counter and comparator.
The original size of the image information that was extracted from the memory areas specified by Z, MB-PSZ, and MC-PSZ and compressed and stored is 2204
3307, the down counter 1 shown in Figure 12
4-1, 12F4H (4852), 14-2, 14-3.
14-4.14-5.1.4-6.14-7.14-8
The comparators each have 1247H (4679),
2H (2).

1247H (4679), 9ABH (2475), dF
9H (3577), 55dH (1373), j247H
(4679), and the "output mode" sets the decompression error counter 1'0-35 to 0 in order to perform decompression from the compressed image memory.The down counter 13-1 of the dither counter shown in FIG. Set IH (1) and IBFH (447) to 13-2 respectively (S
-106-C-5>.

The reader recognizes that there is no RMU memory overflow by issuing the error unit status request command, and stops document scanning. The leader is VSY
Since it does not output NC, RMU receives VSYNC from the reader.
VSYNC to the printer is turned on without waiting (8-106-D-1). In addition, the sub-scanning direction margin VP1
Set the line counter to count 574 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-106-B-22) , S-106-B-23
). In this embodiment, if eight or more decompression errors occur, the decompression error flag is set to - and the copying operation is stopped. The RMU notifies the reader via serial communication that the decompression error has occurred a predetermined number of times (8 times), and the reader does not output any paper feed commands (PRINT) after determining that the decompression error has occurred more than the predetermined number of times, and stops the copy operation. stop.

In order for the RMU to stop the expansion operation, first turn off the V-DEC signal (S-106-D-8), set the number of sub-scanning lines for VR, and after incrementing the line counter, send VSYNC to the printer. I'll turn it off. The reader outputs a printer stop command to notify the printer of stopping the copying operation, and the printer receives this command and stops the copying operation.

If the decompression error does not occur 8 or more times, the RMU repeats the decompression operation (set number of sheets - 1) times, and then stops with the printer stop command from the reader (s-
ro6-C-6).

Next, the memory pass mode will be explained using FIG. This is the mode of transmission.

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

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

After this, the control signal coming from the beamer goes to the printer.
Furthermore, control signals coming from the printer are output as they are to the reader, and the RMU operates as if it were not present. That is, when VSYN (:' from the reader is turned on (S-106-D-1), VSYNC to the printer is turned on, and the image from the reader is sent to the selector 10-23.
(S-106-D-2゜S-106-D-3). And VS from the leader
If YNC is turned off (S-106-D-4), turn off VSYNC to the printer 8-106-D-5)
, and if a printer stop command has been input, the printing operation is stopped. On the other hand, if the printer stop command is not input, the same process is repeated for the set number of times.

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

As a first step to perform a memory overlay operation, image information must be written to the memory. The RMU mode in which image information is written to this memory is the ``memory input mode''.
The instructions are the 2nd byte of the RMU mode instruction command shown in Table 20, the 2nd byte of the RMU memory instruction command shown in Table 21, and the operation section of the rider by the operator as shown in Table 24. Based on the trimming area specification data from <R, MU) from the trimming instruction 1 command
MU) Input the contents of the trimming data of the rimming instruction 6 command from the reader. “In memory input mode 9, the printer start command 100-2 in Table 1 does not need to be output to the printer, and the printer does not perform a copy operation, so the 5DLL shown in Figure 10,
5EL2, 5EL3, 5EL4゜8BL5, video selector selection R-CLK, R-VDA, R-
VB, R-VB, H8YNC.

Set AO and BO (5-106-A-2). Also, since the printer does not perform a copy operation, it does not output the PREQ signal to the RMU, but the RMU outputs the PRBQ 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(
:'-PSZ (paper size of memory C) stores the paper size, and M(:'-METHOD (reading mode of image information stored in memory C area) stores the binary image. do.

Paper size and trimming data entered from the reader HP (
main scanning reference position), VP (III scanning reference position), Hw
(during main scanning), Vw (during sub-scanning), HM (main scanning movement position), and VM (sub-scanning movement position), the down counter (14-1) contains 4677, and the comparator (14-1)
4) 3575 from HP, comparator (14-5)
Set 1371 from Hw, 4677 from the paper size for the comparator (14-8), and 4677 for the dither counter (14-1). Memory address counter (10
-8) is the aforementioned MS (compressed image writing start address)
, Compa 1. -1 (10-14) to set ME (compressed image maximum write address) (s-106-A-
9).

Even if the RMU receives a PRINT signal from the reader (S-
106-A-10), the printer does not perform the copy operation □, so it does not output to the printer, and instead of the printer, VS
Output REQ signal to reader (S-106-A-11
, S-106-A-14). When VSYNC ON is input from the reader (S-106-B'-1'), Fig. 17B
Vp up to the area (1574 in this example) Set Vp in the line counter (10-11) to prevent line compression (S-106-B-2). To detect when 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). Further, Vw during sub-scanning to be compressed (3307 in this example) is set in the line counter (S-106-B-5). Then, the compression operation is repeated in the compressed image memory until the line counter counts up (S-106-B-6, 8-106
-B-7). In order to detect that the line counter has counted up and stop the compression operation, the V-ENC signal is set to t-full (S-to6-B-8). After that, S-106 detects that the VSYNC signal from the reader is turned off.
-B-9), MOVER signal is detected to check whether there is a memory over (memory address counter exceeds the maximum compressed image write address) (Fig. 31, S-106-C-1) ).

If the MOVER signal is at H level, it means that writing to the memory has failed, and a compression failure flag is set to notify the reader of compression failure information (S-106
-C-2). Due to this, the information of R, MU compression failure is added to the above-mentioned 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, depending on the input mode mentioned above, for example, Memo+J
Assume that A4 size image information is compressed and stored in B. Then, transfer this image information to ``Memory Overlay Mode''
Consider decompressing the image, combining it with the image information from the reader, and outputting it to a printer. For decompressed images from the RMU compressed image memory, set bit 5 of the second byte of the RMU mode instruction to “o”.
By doing so, the output is output to the printer at approximately 50% density. In addition, the decompressed image is converted into Hp bits in the main scanning direction.
The second byte of the RMU mode instruction command when outputting to A4 size by trimming the image area of main scanning size Hw bits and sub-scanning size VW bits using the point of Vp bits as a reference point in the sub-scanning direction is from Table 25. ,still,R,
The second byte of the MU memory instruction command is the one in Table 26, 'FLMU trimming instruction command 1 to RMU
) Hp, VP, HW, VW,
Values HM and VM are set and output from the reader to the RMU. R, MU are selectors 1 in Figure 10. Selector 2. Selector 3. Selector 4. Selector 5° Video selector selection R, -VCLK, respectively.

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

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

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

If a paper size instruction command is input from the reader, it is stored separately from the paper size of the compressed image.
The processing for the PREQ signal, PRINT signal, and VSREQ signal is omitted because it is the same as "memory bus mode" or "through ° out mode". Counters are set using Vp, HW, Vw, HM, and VM as follows: 4677 for comparator 14-4, 01 for comparator 14-5, 4677 for comparator 14-8, and 4677 for down counter 13-1.
4677-(Hp -MM) to the counter 13-2, and 4677 to the counter 14-1.If the moving direction of the image is the same as the sub-scanning direction, at the same time as inputting VSYNC ON from the reader (S-106-H~1 ), VSYNC to the printer was turned on (S-106-H-2), V-DEC signal was output to the printer VSYNCJ:'l (VM-VP
) The line is delayed and the line counter is set to set it 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, IFFFH is sent to the comparator 14-6, and 467 is sent to the comparator 14-7.
Set 7.

4677.4677-( for HADR2DADR respectively)
HM-Hp) S-106-H-5), V-
Turn on the DEC signal (8-106-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-H-8, S-106-
H-9), set the TMFL signal so that image expansion is performed S'-106-H-10), set the Vw line to the line counter S-106-H-11), and set the After performing synthesis and performing the synthesis operation for the Vw line (S-106-H-12), turn off the V-DEC signal to stop the expansion operation (S-'
106-H-14).

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

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

Next, the controller 10-2 controls Vw during sub-scanning of the T area.
Count the lines using line counters 10-11 8
-106-I-t 1) It is detected that the image signal of the T area is output to the printer, and the decompression operation is stopped and the VDEC signal is turned off (S-106-I-12).

Now that the controller 10-2 has finished decompressing and outputting the compressed image data, it waits for all images of the reader 10-1 to be output to the printer 10-3 (S-106-4-1
3). When it is detected that the PVSYNC of the reader is turned off, the VSYNC to the printer 10-3 (PVSYNC
) offl.

To finish outputting one image to the printer 10-3 S-1
31 (S-1
Proceed to 06-C-6).

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

Trim the area T in the sub-scanning image where 2=■w and move it to the location where the distance from the starting edge of the sub-scanning paper to t is V4=VM, combine the image signals from the reader and output it to the printer. This corresponds to the case where the controller 10-2
The following control operation is executed according to FIG.

Main scanning image position H,=Hp of T area, main scanning image main scanning image field, and moving the T area in the main scanning direction to 1. from the starting edge of the main scanning paper. If the distance H3 to HM is HM, then the 21st
As shown in the figure, the load value of the counter 1"4-1' (HADR,) is 4677° for the combiner 14-4 which generates the 4677oHAREA signal.
Set O to . The comparator 14-8 that starts the dither counter is set to 4677, and the dither counters 13-1' and 13-2 are set to 4677-(HM-Hp
) is set (8-106-I-'1'). Here, let OSYS be I=cLK (, SE"L 1' (
10-18), and further sets the start address of the compressed image data of U in the memory address counter 1o-8, turns on the V-I)Pc signal, and starts decompression of the 0 image. Here, the line counter 10"-11 counts the line length (Vp - VM) in which the 11 images protrude from the copy paper in the sub-scanning force □ direction. S-10
6-■-3) - Turn off the V-DEC signal and interrupt the expansion operation (S-106-I-4).

Image decompression from this point on is performed using the reader 10-1's VSYNC (P
08YS is FL due to 8BCI (10-18) because it is performed using the clock of reader 10-1 in synchronization with VSYNC).
Select VCK. This can prevent pixels from being misaligned in the main scanning direction when the reader image and the 0 image are combined.

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

This is achieved by setting IFFFH to the comparator 14-6 and 4677 to the comparator 14-7 (8-106-I-7). After this, in order to start the interrupted image expansion, the memory address counter 10
Leave the value -8 as is and turn on the V-DEC signal. Here, the VM lines until the T image is output are counted using the line counter] and O-11 (S-106-
I-9).

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

(19) In this embodiment, the run-length method was used to compress the image, but other compression methods such as MH and MR may also be used. Alternatively, the compressed image signal may be received and input from a telephone line.

As explained above, according to the present invention, even if there is an error in the decompression of a compressed image signal, the line is changed to a normal line image signal and output, so there is no disturbance in the formed image. , it is possible to form a good image.

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 a beam reader, FIG. 3 is a block diagram showing a schematic circuit configuration of a league, and FIG. 5 is a block diagram showing the schematic circuit structure of the printer, FIG. 6 is a diagram showing the contents of the video interface, FIG. 7 is a diagram showing the image signal transmission method, and FIG. Figure 8 is a diagram showing various signals of the video interface, Figure 9 is an explanatory diagram of the encoding operation, and Figure 1
FIG. 0 is a block diagram showing the detailed configuration of the RMU, FIG. 11 is a configuration diagram of a dither counter, FIG. 12 is a configuration diagram of a main scanning counter decoder, FIG. 13 is a diagram showing a trimming state of an original image, and FIG. 15 is a timing chart showing the image signal compression operation, FIG. 15 is a diagram showing the storage state of the memory, FIG. 16 is an explanatory diagram of dither compression, and FIG. 17 is a timing chart showing the image signal expansion operation, Figure 18 is a timing chart diagram showing the operation of the expansion error poem.
9 is a diagram showing the trimming operation related to the main scanning direction and the image movement operation related to the main scanning direction, and FIG. 22(a), (
b) and (C) are diagrams showing the image movement operation in the sub-scanning direction, Figure 23 is a flowchart diagram showing the procedure for serial communication of commands, Figure 24 is a flowchart diagram showing the procedure for serial communication of status, 25 is a flowchart showing the communication procedure before the copy operation, FIG. 26 is a flowchart showing the league operation, FIG. 27 is a flowchart showing the printer operation, and FIG. 28 is a diagram showing the state of the memory area. 29 to 36 are flowcharts showing the operating procedure of the RMU, in which 1-1 is a league, 1-2 is an RMU, 1-3 is a printer, 10-2 is a controller, 10-4 is a compression circuit, 10-5 is compressed image memory, 10-6 is decompression circuit', 10-1!5 is double buffer memory, 10-23 is video selector, to-8
is a memory address counter. -111-1 Garden

Claims (1)

[Claims] an input means for inputting a compressed image; a means for decompressing the compressed image input from the input means; a means for detecting an abnormality in the decompression operation in the decompression means; has a storage means for storing a plurality of lines in the storage means, and means for outputting an image signal read line by line from the storage means, and when the detection means detects an abnormality in the expansion operation of the expansion means, the abnormality is detected. An image processing system characterized in that a normal decompressed image signal stored in the storage means is supplied to the output means in place of the decompressed image signal.