JPH09163153A - Digital copying system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To composite an image with other image and to transfer the resulting image which have been impossible in a conventional system by providing a function of sending data from a reception memory. SOLUTION: In the case of the usual copy mode not using a memory, a switch of a changeover section 56 is thrown to the position B to obtain an output image. In the case of the high speed mode using the memory, the switch of the changeover section 56 is thrown to the position A. When scanning of a 1st original is started, image data subject to various correction are fed to a memory unit 70b. Four lines of data are stored by an FIFO of an input stage and coded by a coding section at an interval of 4 lines and written in a frame memory and also fed to a decoding section. The image data fed to the decoding section are decoded and stored once in an FIFO at an output stage and outputted to a printers. Image data after second and succeeding originals are read from the frame memory, decoded and printed out.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to digital copying systems, and more particularly to image transfer I / O between digital copying machines.
Regarding F (interface).

[0002]

2. Description of the Related Art In a conventional digital copying machine, a method of transferring uncompressed raw data together with a main scanning gate signal and a sub scanning gate signal, a FAX (facsimile apparatus)
As described above, there is a method in which variable-length coding is performed once and then transferred. In addition, as in Japanese Patent Laid-Open No. 2-60277, the read image data is once stored in the memory as it is, and then the SCSI (Small computer systems interfac
Some devices are distributed to peripheral models via I / F such as e).

[0003]

(Problems to be solved by the invention of claim 1) When the printing speed is increased by using the memory unit attached to the copying machine, the first original document has been used so far. Is read and stored in memory while being printed out. However, if an irreversible compression device is used in the memory storage part, a difference occurs between the first output image that is output without passing through the memory and the second and subsequent output images that are output while being read from the memory. There was a problem.

(Problem to be solved by the invention of claim 2) Conventionally, when a printing speed is increased by using a memory unit, raw data is taken into a memory and transferred. Therefore, a large capacity image memory is required. Further, in order to perform transmission in real time, an I / F having a very high transfer rate is required.

(Problem to be Solved by the Invention of Claim 3) In the format of claim 1, since the printer operation cannot be performed during the data transfer, the productivity of the entire apparatus may decrease. .

[0006]

According to a first aspect of the present invention, there is provided a light source for illuminating a document, an optical system for focusing the document on a sensor, an image reading device using a line image sensor, and an input image. An image processing device for performing image quality processing on data, a device for compressing data after image processing by a fixed-length block coding compression method, a semiconductor memory for storing the compressed image data, and a compression device are independent. Characterized in that it has a device for decoding the block compressed data stored in the semiconductor memory that operates in accordance with the above, and a plotter for printing the decoded image data, whereby the encoder and the decoder can be operated simultaneously. Therefore, it is possible to output even the first output image data through the encoder and the decoder.
This makes it possible to obtain a copying machine in which there is no difference in image quality between the first and second and subsequent output images.

According to a second aspect of the present invention, in the digital copying system according to the first aspect, there is provided a function of transferring the compressed image data written in the semiconductor memory to an opponent machine. , Has a video I / F that transfers the processed and edited encoded data stored in the memory to an external device, so that the composite edited image can be transferred to the opponent machine in real time and printed out. It was done.

According to a third aspect of the present invention, there is provided a bus for decoding the image data after the data compression by the block coding and transferring the image data to the opponent machine, and transferring the decoded image data to the printer. With the function to decrypt and print the transferred data,
Therefore, the printing operation can be performed even during the data transfer, and the data transfer can be performed without reducing the throughput of the entire apparatus.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention of claim 1 has a configuration in which an encoder and a decoder can be operated at the same time. Therefore, the encoder and the decoder can be applied to the first output image data. Since it is possible to output through the above, it is possible to obtain a copying machine in which there is no difference in image quality between the output images of the first and second sheets. The invention of claim 2 has a video I / F for transferring the coded data which has been processed and edited and stored in the memory to an external device, and therefore, the composite edited image is transferred to the opponent machine in real time and printed out. can do. The invention of claim 3 has a function of decoding and printing while transferring the data stored in the memory, and therefore, the printing operation can be performed even during the data transfer, so that the throughput of the entire apparatus is reduced. Data can be transferred without any need.

FIG. 1 is a front view showing a schematic configuration of a digital copying apparatus according to the present invention. As is well known, a contact glass 2 for placing a document is provided on the upper surface of the copying apparatus 1, and a lower portion of the contact glass 2 is horizontal. The light source 4 is arranged as a traveling body 5 so as to be movable (movement in the sub-scanning direction). In the traveling body 5,
A mirror 3 for reflecting the light from the light source 4 reflected by the document in the horizontal direction is provided integrally with the light source 4. Further, a traveling body having a mirror 6 and a mirror 7 for sequentially reflecting the light from the mirror 3 by 90 degrees is provided so as to be able to travel according to the movement of the light source 4. That is, the mirror 6 is provided to reflect the light from the mirror 3 downward, and the mirror 7 that reflects the light from the mirror 6 in the opposite direction to the light from the mirror 6 is provided below the mirror 6. ing. A lens 8 is arranged in the reflected light path from the mirror 7, and a line image sensor (CC
D) 9 is provided.

FIG. 2 is a diagram showing an electric circuit of the image signal system. The image signal read by the CCD 9 is A / D converted by the video processing unit 40 with proper gain and synchronized with ck1. 8-bit digital data DA
It is output as TA0 to 7. Video processing unit 40
For CC, which determines the CCD read timing
The image processing unit 50 sends the DSTN and CK1, which is a 10 MHz clock. Image processing unit 5
At 0, black offset correction 51 and shading correction 5
2. Image quality processing 5 such as γ correction and dithering and error diffusion after MTF correction 53 and electric scaling 54 in the main scanning direction are performed.
5 is performed.

Next, the function of each block will be described. The black offset correction is a correction for subtracting the black level of the dark current of the CCD from the image data. The shading correction eliminates the unevenness of the light amount of the light source in the main scanning direction and the unevenness due to the difference in sensitivity between pixels of the CCD. The correction is performed by dividing the image data being read by the stored white plate data for each pixel. MTF correction refers to the deterioration of optical frequency characteristics, etc.
It is corrected by a three-dimensional spatial filter. In the scaling circuit, the scaling process in the main scanning direction is performed by using the interpolation calculation by the three-dimensional convolution method. After the γ conversion, the image quality processing unit performs character processing, error diffusion processing, dither processing, etc. according to the mode.

Image data SDT0 after a series of processing
7 to 7 are printer control units 61 of the printer control unit 60.
To the LD modulation plate 62 after performing speed conversion according to the write clock sent to the LD modulation plate 62. The LD modulation plate 62 controls the pulse width and the amount of current supplied to the semiconductor laser 80 according to the 8-bit 256-gradation image data.

The γ-corrected data is sent to the memory / transfer unit 70, where image data is compressed / decompressed, accumulated, and transferred to the counter unit. This part will be described in detail later. The IPU shares an address bus and a data bus with the CPU of the main control board, and communication is performed via this. The main control board controls the motor of the scanner printer. Besides that, it also controls various clutches and solenoids.

In FIG. 1, the printer unit includes an optical system 2 for focusing a laser beam from a laser generator 22 on a predetermined position.
3, a reflecting mirror 24 for reflecting the output light of the optical system 23,
The photoconductor drum 12 to which the beam from the reflecting mirror 24 is exposed, the charger 20 that uniformly charges the photoconductor before exposure, the developing device 14 that develops the electrostatic latent image by exposure with toner, and the transfer position. A resist roller 27 that feeds transfer sheets at the same timing, a cassette 34 in which a large number of transfer sheets are set, a cassette 35 in which sheets of different size from the cassette 34 are set, and a single sheet is fed from the cassette 34. Paper roller 26, cassette 35
A sheet feeding roller 26 that feeds only one sheet from the transfer roller 18, a transfer charger 18 that transfers the toner image on the photoconductor drum 12 to the transfer sheet that is fed from the registration roller 27,
A separation charger 19 for peeling off the portion of the paper after transfer from the photoconductor drum 12, a conveyor belt 30 for conveying the separated transfer paper, and a toner image adhered to the transfer paper conveyed by the conveyor belt 30 is fixed. Fixer 3
1, a cleaning device 21 for removing the residual toner adhering to the surface of the photosensitive drum 12, and a discharge tray 33 for accommodating the transfer paper from the fixing device 31.

In FIG. 1, a laser generator 22 is modulated and driven according to image information, and reaches a photosensitive drum 12 which has been charged in advance by a charging charger 20 through an optical system 23 and a reflecting mirror 24, Form a latent image. This latent image reaches the opposing position of the developing device 14 according to the rotation of the photosensitive drum 12, and toner development is performed on the latent image.
The paper sent from the cassette 34 or the cassette 35 is fed from the registration roller 27 at the timing when the visible image formed by the toner development reaches the transfer position, and is transferred by the transfer charger 18 at the transfer position. The upper toner image sticks to the paper surface. The transfer-completed paper is peeled off from the leading edge of the paper by the static eliminator charger 19 and sent onto the conveyor belt 30. The paper on the conveyor belt 30 is carried into the fixing device 31, and is given heat and pressure to fix the toner image on the paper surface. The transfer sheet on which the fixing is completed is sent to the discharge tray 33.

In the above description, when the image is normally read in the original reading mode, the contact glass 2 is used.
Place the original with the image side facing down and press the start button. As a result, a scan start signal is output from the CPU to the image processing unit, and FGATEN indicating the image effective range in the sub-scanning direction becomes ACTIVE. The traveling body 5 starts moving leftward in FIG. 1, and the sub-scanning of the document is performed. The reflected light (reading light) from the document illuminated by the light source 4 reaches the line image sensor 9 through the mirror 3, the mirror 6, the mirror 7, and the lens 8 in this order.
The line image sensor 9 converts incident light into an electric signal, A / D-converts it in the video processing unit 40, and sends it to the image processing unit 50. The data sent to the image processing unit 50 includes black offset correction 51, shading correction 52, MTF correction 53, and electrical scaling 5 in the main scanning direction.
After step 4, image quality processing 55 such as γ correction and dither and error diffusion is performed. Then, the image data is sent to the printer control unit section 60. Normal copy is FG
Almost at the same time as the generation of ATE, DFGATEN of the operation start signal of the printer becomes ACTIVE and writing to the printer is performed. The above is the copy operation in the normal mode.

Next, a case will be described in which the memory / transfer unit 70 transfers image data while compressing and storing the image data in the memory / transfer unit 70, and decoding and outputting the image. The image data from the image processing unit 50 is encoded and stored in the memory / transfer unit 70. When outputting an image from the memory / transfer unit 70, the code is decoded and output. Here, the internal configuration of the memory / transfer unit 70 is shown in FIG.

Next, the operation of transmitting data will be described with reference to FIG. In FIG. 3, image data MU_
IN is a sub-scanning gate signal mifgate, a main scanning gate signal milgate, and a main scanning synchronization signal milsync.
And are sequentially taken into the 4-line FIFO 71 at the timing of FIG. When data for four lines is stored once and the data for the fifth line is fetched, mi_
en becomes active and is fetched from the FIFO 71 into the encoding unit 72 for each 4 × 4 pixel block and encoded.
The format of the data at this time is La, L as shown in FIG.
8 bytes of data obtained by adding dummy 2 bytes of data to 6 bytes of d and φij is the basic clock 20.
It is output to CMP_OUT in the period of 16 clocks of MHz. In this way, since the data is compressed to 1/2 of the original data, the clock rate after this is half that of 10
MHz. This data is the DRAM controller 73
And the data other than the dummy portion is stored in the 12 Mbite frame memory 74 and simultaneously sent to the data rate converter 75. In the data rate conversion unit 75, FIG.
, Write enable mi_en, clk
Is divided into two and connected to wck to fetch the data CMP_OUT into the FIFOs 76a and 76b having the 8K × 8 bit configuration.

In FIG. 4, when the reading of the data of the 9th line is started, SOLGATE becomes active and the data is transmitted from the FIFO. The read clock at this time can be freely selected within a limit of half the frequency of the basic clock. There are two FIFOs, and while writing to one FIFO 76a (76b), the other FIFO 76b (76a)
Toggle operation to read data from. Data to be sent send_out [7: 0], solg
ate and clk are transmitted by a differential driver such as RS422 and a balanced line such as a twisted wire.

Next, the operation of receiving data will be described. The data sent from the counter unit is converted into a TTL level signal by the receiver section in FIG. The wck of the FIFO memory of the data speed conversion unit 75 is s
ck is connected. Two FIFO wens are sil
The gate is toggled and the data send_in is fetched instead of the respective FIFOs 76a (76b). The data taken into the FIFO is read by mem_en generated by the data rate conversion unit 75. mem_en is the DRAM controller 73
Is also a trigger for writing in the frame memory 74, and the data date_in is written in a predetermined location in the frame memory 74 in accordance with the memory write start address and the image main scanning size sent in advance. The above is the description regarding the basic operation of the memory unit.

Next, the inside of the encoding unit will be described with reference to the block diagram of FIG. 4 input to the encoding unit 72
As shown in FIG. 7, the line image data is input to the maximum value / minimum value calculation unit 72a, and the maximum value Lmax and the minimum value Lmin are calculated for each 4 × 4 pixel block. Lm
ax and Lmin are input to the La and Ld calculation unit 72b,
La = (Lmax + Lmin) / 2, Ld = (Lmax−
Lmin) / 2 is calculated. The data of La and Ld are stored in the frame memory as coded data, while P
It is input to the 1, P2 calculating unit 72c, and P1, P2 are calculated. At this time, the calculation formula of P1 and P2 is P1 = La +
1 / 2Ld, P2 = La-1 / 2Ld. The obtained values of P1, P2 and La are input to the code allocating unit 72e, and in the code allocating unit 72e, the above Lmax and Lmi.
The pixel block data for which the values of n, La, Ld, P1 and P2 have been obtained are input at a timed timing by a delay buffer 72d composed of a flip-flop or the like. The code assigning unit 72e compares the values of P1, P2, and La with the data of the input pixel block,
A 2-bit code φij is assigned to each pixel and stored in the frame memory. The above is the description of the inside of the encoding unit 72.

FIG. 8 is a block diagram of the inside of the decoding unit 77. La and Ld for one pixel block are read from the memory and input to the Q1 to Q4 calculation units. The Q1 to Q4 calculator 77a calculates according to the following equation. Q1 = La + 3 / 4Ld Q2 = La + 1 / 4Ld Q3 = La-1 / 4Ld Q4 = La-3 / 4Ld In the quantized value assigning unit 77b, by assigning the 2-bit code φij to the quantized values Q1 to Q4, Decoded image data for each block is output. The memory unit 70b in the memory / transfer unit 70 in FIG. 2 performs the above-described series of encoding / decoding processing, and by connecting the signal switching unit 56 in the image processing unit 50 in FIG. 2 to the A side, By inputting the decoded image data from the image storage unit to the image output unit, the output of the decoded image can be obtained from the image output unit.

Next, an embodiment of the invention of claim 1 will be described. In the case of a copy operation that does not use normal memory,
The switch of the switching unit 56 in FIG. 2 is connected to the B side to obtain an output image. In the case of the high speed mode using the memory, the switch of the switching unit 56 is connected to the A side. 1
When the scanning of the first document is started, the various corrected image data is sent to the memory unit 70b. Data is stored for four lines by the FIFO 71 of the input stage. The stored data is encoded by the encoding unit 72 every four lines, written in the frame memory 74, and at the same time sent to the decoding unit 77 as it is. The image data sent to the decoding unit 77 is once stored in the decoded output stage FIFO 78 and output to the printer. For the second and subsequent sheets, the image data read from the frame memory is decoded and printed out. In this way, since the image that has passed through the encoder and the decoder is printed out even for the first image data in the high-speed mode operation using the memory, the output of the first and second and subsequent images is performed. The images are never different.

Next, an embodiment of the invention of claim 2 will be described. Here, the structure of a digital PPC having an I / F capable of sending the compressed data stored in the frame memory 74 to the counter device will be described. To do. 12 Mbyte
The compressed image data stored in the frame memory 74 is sequentially read through the DRAM controller 73 and sent to the data speed conversion unit 75. FIG. 10 shows the configuration of the data rate conversion unit 75 at this time. The read data data_out is 1200 continuous 8-byte data obtained by compressing image data of 4 × 4 pixels, and is data obtained by compressing data for four main scanning lines.

The read start address of data from the DRAM controller 73 and the data length of one block are C in advance.
Given by PU. With this information memo_en
Is made. memo_en is switched for each line to create a wen for the toggle operation of the FIFOs 76a and 76b. The data is once stored in the FIFO memory with the internal clock c.
It is taken in by lk. Next, data is read from the FIFO at the clock frequency for transmission. solg
The ate generation block generates strobe signal solgate corresponding to the data transmission length from mem_en and ren1 and ren2 for toggle reading of the FIFO. Data is read from the FIFOs 76a and 76b by a toggle using these signals. The read data is sent to the outside by the differential driver. At this time, the relationship between the format of the data to be transmitted and the solgate is exactly the same as the relationship between the data SEND_OUT and solgate in FIG. Therefore, from the viewpoint of the receiving machine, there is no distinction as to whether the video data on the transmission side is directly transmitted or the image data once stored in the memory. By enabling such an operation, it becomes possible to send the image data once stored in the frame memory and subjected to the edit processing operation to the opponent machine.

Next, an embodiment of the invention of claim 3 will be described. The compressed image data stored in the 12 Mbyte frame memory 74 is sequentially read through the DRAM controller 73 and sent to the data speed conversion unit 75. FIG. 10 shows the configuration of the data rate conversion unit at this time. The read data data_out is 4 ×
1 byte of 8-byte data compressed from 4-pixel image data
The number of continuous 200 lines is obtained by compressing the data for four main scanning lines. The data from the frame memory 74 is sent to the data rate converter 75 and at the same time to the decoder 77. The data sent to the decoding unit 77 are sequentially combined as described above, and the output FIF
4 lines are input to O78 at the same time. When data for four lines is prepared, the data is read line by line, sent to the printer control unit 60, and printed out.

At the same time, the data sent to the data rate converter 75 is once fetched in the FIFO memory. here,
The read start address of data from the DRAM controller 73 and the data length of one block are given in advance by the CPU. With this information, memo_en is created in the same manner as the embodiment of claim 2, and is stored in the FIFO memory by the internal clock clk. Next, FIFO
The data is read at the transmission clock frequency. The solgate generation block 76c is memo_e
Strobe signal solga corresponding to the data transmission length from n
ren and ren for te and FIFO toggle read
2 is generated. By these signals, data is read from the FIFO by toggle. As described above, the machine of this embodiment has a function of decoding the image data, which is once stored in the frame memory and subjected to the editing processing operation, to the opponent machine, and decodes and prints it out by the decoding unit. Therefore, the printing operation can be performed even when the data is transferred to the counter unit, and the productivity of the entire apparatus is improved.

[0029]

According to the first aspect of the present invention, a light source for illuminating an original, an optical system for forming an image of the original on a sensor, an image reading apparatus using a line image sensor, and image quality processing for input image data. An image processing apparatus for performing the image processing, an apparatus for compressing the data after the image processing by a fixed-length block coding compression method, a semiconductor memory for storing the compressed image data, and a semiconductor operating independently of the compression apparatus. It is characterized by having a device for decoding the block compressed data stored in the memory and a plotter for printing the decoded image data. Therefore, since it has a function of moving the encoder and the decoder at the same time, The result of encoding / decoding can be obtained from the output image of the first sheet, so that the difference between the images of the print outputs of the first sheet and the second and subsequent sheets does not occur.

According to a second aspect of the present invention, in the digital copying system according to the first aspect, there is a function of transferring the compressed image data written in the semiconductor memory to a counter device, and therefore, Since it has a function to transfer the data encoded and stored in the memory to the opponent, it is possible to store the image data in the frame memory once and transfer the image data that has undergone some editing processing to the opponent and output it. The productivity is not reduced even when performing complicated editing.

According to a third aspect of the present invention, in the digital copying system according to the second aspect, there is a bus for decoding and transferring the image data after the data compression by the block coding to the opponent machine while decoding the image data. Therefore, since it has a function to print out while encoding and storing the data stored in the memory to the counter machine, the image data stored once in the frame memory and subjected to some editing processing is performed. Can be output while being transferred to the opponent machine, and productivity is not reduced even during complicated editing processing.

[Brief description of the drawings]

FIG. 1 is a front view of a digital copying machine to which the present invention is applied.

FIG. 2 is a block diagram of an electrical system according to the present invention.

FIG. 3 is a block diagram of a memory / transfer unit according to the present invention.

FIG. 4 is a timing chart of a memory / transfer unit according to the present invention.

FIG. 5 is a data block configuration diagram of compressed data according to the present invention.

FIG. 6 is a configuration (during transmission) diagram of a data rate conversion unit according to the present invention.

FIG. 7 is a block diagram of an encoding unit according to the present invention.

FIG. 8 is a block diagram of a decoding unit according to the present invention.

FIG. 9 is a diagram (at the time of reception) of a data rate conversion unit according to the present invention.

FIG. 10 is a diagram (at the time of memory transmission) of a data rate conversion unit according to the present invention.

[Explanation of symbols]

40 ... video processing unit, 50 ... image processing unit,
60 ... Printer control unit, 70 ... Memory transfer unit, 71, 78 ... FIFO memory, 72 ... Encoding section, 7
3 ... DRAM controller, 74 ... Frame memory, 7
5 ... Data rate conversion unit, 77 ... Decoding unit.

Claims (3)

[Claims] 1. A light source for irradiating a document, an optical system for focusing the document on a sensor, an image reading device using a line image sensor, and an image processing device for processing image quality of input image data. A device for compressing data after image processing by a fixed-length block coding compression method, a semiconductor memory for storing the compressed image data, and a block stored in a semiconductor memory that operates independently of the compression device. A digital copying system comprising a device for decoding compressed data and a plotter for printing the decoded image data. 2. The digital copying system according to claim 1, which has a function of transferring the compressed image data written in the semiconductor memory to a counter device. 3. The digital copying system according to claim 2, further comprising a bus for decoding and transferring the image data after the data compression by the block coding to the counter, while transferring the image data to the opponent machine. Digital copying system.