JPH0514649A - Image forming device - Google Patents

Abstract

PURPOSE:To make the operation of the device efficient without increasing the cost of a memory by utilizing the memory effectively. CONSTITUTION:The device is provided with an image process unit IPV 803 having a data depth switching device section revising a quantization level of a picture data, a memory device (MEM) 804 storing a picture data in a package, a scanner control circuit 800 outputting a control signal to the IPU 803 and the MEM 804 and a main control panel 701 controlling the entire device based on the picture data quantity stored in the MEM 804.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus applied to a digital copying machine, a facsimile machine and the like, and more particularly to an image forming apparatus which efficiently uses a memory.

[0002]

2. Description of the Related Art In some image forming apparatuses, image data of a plurality of originals can be stored in a memory. Conventionally, a black and white binary image signal has been widely used as image data, but in recent years, in order to improve image quality, one pixel is represented by a multi-valued signal such as 8 bits or 4 bits. There is something.

FIG. 21 is a block diagram showing a flow of processing image data in a conventional image forming apparatus. In FIG. 21, an image processor (IPU) 2201
The image data output from the memory device (M
EM) 2202, then MEM when needed
The stored data is retrieved from the 2202 and the printer (P
It was output to R). A method is generally used in which the image data output from the IPU 2201 is output to the printer (PR), the data is simultaneously stored in the MEM 2202, and the second and subsequent copying processes are performed using the image data from the MEM 2202. It was Further, in a conventional digital copying machine or the like, when storing binary image data in a storage unit, data processing is executed using a compressor and an expander in order to reduce the data capacity.

[0004]

However, according to the image forming apparatus using the multi-valued image data, the image data cannot be compressed by the MH coding, the MR system, etc., so that the data amount becomes enormous. Occasionally, the image data that is undergoing image formation cannot be stored in memory,
For example, in an image forming apparatus equipped with a large sorter that causes a large number of recording papers to be present in the machine during continuous copying, one recording paper causes a jam when there are a large number of recording papers in the machine. If the image data is not stored in the memory, the jammed recording paper must be removed from the device, and the original document that was not copied normally must be scanned again to read the image data. However, there is a problem in that it is troublesome to deal with the post-processing when an abnormality occurs in the device, in other words, the device cannot be operated efficiently.

Increasing the capacity of the memory in order to solve the above problems raises the cost of the memory.

The present invention has been made in view of the above, and an object of the present invention is to effectively utilize a memory to improve the efficiency of operation of the apparatus without increasing the cost of the memory.

[0007]

In order to achieve the above object, the present invention provides an image processing means for performing predetermined image processing such as shading correction and MTF correction on image data input through the input means, and an image processing means. In an image forming apparatus having a storage unit for storing image data image-processed by the processing unit, the corresponding image data is held in the storage unit until the image forming operation is normally completed, and the image forming operation is normal. The present invention provides an image forming apparatus including a control unit that executes an image forming operation using the image data stored in the storage unit when the processing is not completed.

Further, in the above-mentioned structure, the image processing means automatically makes an image when the number of originals of the image data stored in the storage means or the amount of image data stored in the storage means exceeds a predetermined value. It is desirable to change the quantization level of data. Further, it is desirable that the image processing means changes the quantization level by using a switching circuit for the quantum number.

Further, based on the quantization level of the image data, only effective data is extracted from the image data, the image data is converted into an effective data width, and a plurality of effective data widths are obtained based on the data width of the storage area of the storage means. It is desirable to provide a data width conversion means for storing the image data having the effective data width of 1 in the storage means.

Further, when the image data stored in the storage means exceeds the storage capacity of the storage means, or when a predetermined amount or more of image data is stored in the storage capacity, the recording paper is automatically fed. It is desirable to have a paper feed control means for limiting.

[0011]

According to the image forming apparatus of the present invention, when the number of originals of the image data stored in the storage means or the amount of the image data exceeds a predetermined value, the image processing means automatically determines the quantum of the image data. The conversion level is changed, and the data width conversion means packs the image data so as to match the quantization level of the image data and fits the data width of the storage area, and stores it in the storage means. The paper feed control means limits the paper feed of the recording paper when the image data stored in the storage means exceeds the storage capacity of the storage means, or when a predetermined amount or more of image data is stored. The control unit retains the image data stored in the storage unit until the image forming operation is normally completed. On the contrary, when an abnormality (for example, a recording paper jam) occurs during the image forming operation, the image forming operation is performed. The operation is performed by reading the image data stored in the storage means.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the image forming apparatus of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a schematic configuration of a digital copying machine which is an image forming apparatus of this embodiment. The digital copying machine is roughly classified into a copying machine main body 100, an automatic document feeder (ADF) 200, a sorter 300, and It is composed of four units including a double-sided reversing unit 400.

FIG. 2 shows the structure of the copying machine main body 100.
The scanner unit, the writing unit, the photoconductor unit, the developing unit, and the paper feeding unit are provided. Hereinafter, the configuration and operation of each of these units will be described in detail.

[Scanner Unit] The scanner unit includes a reflecting mirror 10.
1, a first light source 102, and a first mirror 103, which are equipped with a first mirror 103 and move at a constant speed, and a second mirror 10.
4 and a third mirror 105, and a second scanner that moves following the first scanner at a speed half that of the first scanner. An original document (not shown) on the contact glass 106 is optically scanned by the first scanner and the second scanner, and the reflection image is scanned by the color filter 107.
The image is guided to the lens 108 via the one-dimensional fixed image pickup device 10
Image on 9.

A fluorescent lamp or a halogen lamp is used as the light source 102, but a fluorescent lamp is generally used because of its stable wavelength and long life. In this embodiment, the reflecting mirror 101 is attached to one light source 102, but two or more light sources 102 may be used. Since the fixed image pickup device 109 described above has a fixed sample clock, the fluorescent lamp will adversely affect the image unless it is lit at a higher frequency.

The fixed image pickup device 109 is generally a CC
D is used. Since the image signal read by the fixed image pickup device (hereinafter, referred to as CCD image pickup device) 109 is an analog value, analog / digital (A / D) conversion is performed.
Various kinds of image processing (for example, binarization processing, multi-value processing, gradation processing, scaling processing, editing processing, etc.) are performed on the image processing board 110, and converted into digital signals as a set of spots.

In order to obtain color image information, in the present embodiment, a color filter 107 that allows only the necessary color information to pass through is disposed in the optical path guided from the document to the CCD image pickup device 109. The color filter 107 is moved in and out in accordance with the scanning of the original, and the functions such as multiple transfer and double-sided copy are activated each time, so that various kinds of copies can be created. The marker on the original image can be read in the copy mode.

[Writing Section] The image information after the image processing is
In the writing unit, the data is written on the photosensitive drum 111 in the form of a set of light spots by raster scanning of laser light. A He-Ne laser is conventionally used as this laser light source. The wavelength of the He-Ne laser is 633 nm,
It is used because it matches well with the sensitivity of copying photoconductors, but since this laser light source itself is very expensive and it is not possible to directly modulate it, there are inconveniences such as the complexity of the device. Due to the increased sensitivity in the long wavelength region of the body, inexpensive semiconductor lasers capable of direct modulation have been used. Also in this embodiment, this semiconductor laser is used as a laser light source.

FIG. 3 shows a plan view of this writing section.
The laser light emitted from the semiconductor laser 112 is converted into a parallel light flux by the collimator lens 113, and the aperture 1
The light beam is shaped into a light beam having a constant shape by 14. The shaped laser light enters the polygon mirror 116 in a form compressed by the first cylinder lens 115 in the sub-scanning direction.

The polygon mirror 116 has an accurate polygonal shape, and is rotated at a constant speed in a constant direction by a polygon motor 117 (see FIG. 2). This rotation speed is
It is determined by the rotation speed and writing density of the photosensitive drum 111 and the area of the polygon mirror 116.

The reflected light of the laser light incident on the polygon mirror 116 is deflected by the rotation of the polygon mirror 116. The deflected laser light is reflected by the fθ lens 118.
A, 118b and 118c are sequentially incident. fθ lens 1
18a, 118b, 118c convert scanning light having a constant angular velocity so as to scan the photosensitive drum 111 at a constant speed,
An image is formed on the photosensitive drum 111 so that the light spot becomes the minimum light spot,
It also has a face tilt correction mechanism.

Fθ lens 118a, 118b, 118c
The laser light that has passed through the
The image data is output for one line after a certain period of time after the synchronization signal for outputting the cueing signal in the main scanning direction is output from the synchronization detection sensor 120 by 9 and one image is formed by repeating this. become.

[Photosensitive Member] A photosensitive layer is formed around the photosensitive drum 111. Semiconductor laser light (wavelength 780
nm) as the photosensitive layer having a sensitivity to
PC), α-Si, Se-Te, etc. are known, and in this embodiment, an organic photoconductor (OPC) is used. Generally, in the case of laser writing, the negative /
Positive (N / P) process and positive that shines light on the background
There are two types of positive (P / P) processes. In this embodiment, the former N / P process is adopted.

The charging charger 121 is of the scorotron type having a grit on the side of the photoconductor, uniformly (-) charges the surface of the photoconductor drum 111, and irradiates the image forming portion with laser light to change the potential of the portion. Drop it. Then, the background portion of the surface of the photoconductor drum 111 is -750 to -800.
V, the image portion has a potential of about -500 V, and an electrostatic latent image is formed on the surface of the photosensitive drum 111. This is applied to the developing roller by the developing units 122a and 122b from -500 to -60.
A bias voltage of 0 V is applied to attach (-) charged toner to make the electrostatic latent image visible.

[Developing Section] In the color copying machine of this embodiment,
As shown in the figure, the main developing device 122a and the sub-developing device 122b
Equipped with two developing devices. Sub-developing device 1 for solid black
22b and the toner replenishing device 123b are removed. In this embodiment having two developing devices, the main developing device 12
Toner replenishing device 1 that pairs black toner into toner replenishing device 123a that pairs with 2a and sub-developing device 122b
By putting a color toner in 23b, the development is selectively performed by changing the main pole position of the multi-color developing device during the development of one color.

This development is performed by the color filter 107 of the scanner.
It becomes possible to read color information by switching between, and to perform multi-function color copying and color editing by combining with the multi-transfer of the paper transport system and the double-sided copying function. For developing three or more colors, a method of arranging three or more developing devices around the photosensitive drum 111,
There is a revolver system in which three or more developing devices are rotated and switched.

The image visualized by the developing devices 122a and 122b is transferred onto the recording paper, which has been synchronized and sent to the photosensitive drum 111, from the back surface of the paper with a (+) charge applied by the transfer charger 123. To be done. The transferred recording paper is subjected to AC neutralization by a separation charger 124 which is integrally held with the transfer charger 123, and the photosensitive drum 1
Separated from 11.

On the other hand, the toner remaining on the photosensitive drum 111 without being transferred onto the recording paper is cleaned by the cleaning blade 12.
It is scraped off from the photoconductor drum 111 by 5 and collected by the attached tongue 126. Further, the photosensitive drum 111
The potential pattern remaining in the area is erased by irradiating the static elimination lamp 127 with light.

[Sheet Feeder] In the present embodiment, a plurality of cassettes 128a, 128b, 128c are provided, and the recording paper which has been transferred once is passed through the re-feeding loop 129 to enable double-sided copying or re-feeding. ing.

A plurality of cassettes 128a, 128b, 12
When one of the cassettes 8c is selected and a predetermined start button is pressed, the paper feed rollers (130a, 130b, 130c) near the selected cassette
Is rotated and is fed until the leading end of the recording paper hits the registration roller 131. At this time, the registration roller 131
Is stopped, the rotation is started at the timing of the image position formed on the photoconductor drum 111, and the recording paper is fed to the periphery of the photoconductor drum 111. After that, the toner image on the recording paper is transferred at the transfer unit, and the separation / conveyance unit 132
The toner image transferred by suction is fixed on the recording paper by a fixing roller composed of a pair of heat roller 133 and pressure roller 134.

The recording sheet transferred in this manner is guided to the sheet discharge port on the sorter 300 side (see FIG. 1) by the switching claw 135 during normal copying. On the other hand, during multiple copy,
The direction is not changed by the switching claws 136 and 137, passes through the lower sheet re-feeding loop 129, and is guided to the registration roller 131 again.

When performing double-sided copying, the copying machine main body 100 is used.
There are two cases, that is, only the case and the case where the double-sided reversing unit 400 (see FIG. 1) is used. Here, the former case will be described. The recording paper guided downward by the switching claw 135 is further guided downward by the switching claw 136, and then sent by the switching claw 137 to a tray (not shown) further below the re-feeding loop 129. By reversing the roller 138, it is fed again in the opposite direction, and by switching the switching claw 137, it is guided to the refeeding loop 129 and fed to the registration roller 131.

[ADF] FIG. 4 shows the configuration of the ADF 200. The ADF 200 automatically guides the originals one by one onto the contact glass 106 and automatically ejects the originals after copying. A stack of documents (not shown) placed on the document feed tray 201 is aligned in the width direction of the documents by the side guides 202. The placed document is the paper feed roller 20.
At 3, the sheets are separated and fed one by one, and are conveyed to a predetermined position on the contact glass 106 by the rotation of the conveyor belt 204 and positioned.

When the copying of the predetermined number of sheets is completed, the original is discharged to the discharge tray 205 by rotating the conveyor belt 204 again. Although not described in detail, the side guide 20
By counting the position of 2 and the feeding time of the original,
The document size is being detected.

[Sorter] FIG. 5 shows the structure of the sorter 300. The sorter 300 sorts the recording paper discharged from the copying machine main body 100 into, for example, page order, page by page, or a preset bin 301.
It is a device for selectively feeding a to 301x. Motor 3
The recording paper conveyed by the plurality of rollers rotatably driven by No. 02 is the selected bin 301 by switching the claws (not shown) near the entrances of the bins 301a to 301x.
a to 301x.

[Double-Sided Reversing Unit] FIG. 6 shows the structure of the double-sided reversing unit 400. As described above, the copying machine main body 100 side can perform only double-sided copying for each sheet, but by attaching the double-sided reversing unit 400, double-sided copying can be collectively performed.

When performing a double-sided copy collectively for a plurality of sheets, in the copying machine main body 100 (see FIG. 2), the recording paper which has been fixed is transferred to the double-sided reversing unit 400 via the switching claws 135 and 136. Sent. The recording paper that has entered the double-sided reversing unit 400 is discharged to the tray 4 by the paper discharge roller 401.
It is accumulated on 02. At this time, the recording paper is fed by the feed roller 4
03 and the side alignment guide 404 aligns the vertical and horizontal directions. The recording sheets accumulated on the tray 402 are re-fed by the re-feeding rollers 405 when the back side is copied. At this time, the recording paper sent to the copying machine main body 100 side is directly guided to the re-feed loop 129 by the switching claw 136 and the switching claw 137 (see FIG. 2).

[Control Unit] FIG. 7 is a block diagram showing the overall configuration of the control system in the digital copying machine according to this embodiment. In the figure, reference numeral 701 is a main control board for controlling the entire digital copying machine, and 702 is an ADF2.
ADF control board for controlling 00, 703 is a sorter 300
704 is a sorter control plate that controls the double-sided reversing unit 400, 705 is a paper feed control plate that performs various control of the paper feed unit, 706 is an application system, 707 is a fixing sensor, a density sensor, Reference numeral 708 denotes a sensor such as a registration sensor, 708 is a fan such as an APL fan or exhaust fan, 709 is a counter such as a total counter or a key counter, and 710 is a fixing thermistor for detecting the surface temperature of the fixing roller.

Further, 711 is an LD control plate for controlling the semiconductor laser 112, 712 is a PWM control plate, 713 is a drive plate for driving the polygon motor 117, 714 is a drive plate for driving the main motor 714a, and 715 is a fixing roller. Fixing heater and thermal fuse to prevent overheating, 71
6 is an AC drive plate that serves as an AC power source for a fixing heater, 7
Reference numeral 17 denotes a DC power source that rectifies the AC from the AC driver 716 into DC and serves as a drive source for each DC drive component. Blade SOL (solenoid) for separating operation, first to third
Pickup SOL (solenoid), first to second lock S
OL (solenoid), 719 is a registration CL (clutch) for drivingly transmitting to the registration rollers 131, and a rising relay CL
(Clutch), first to third sheet feeding CL (clutch), 720
Is a sensor related to the sheet feeding unit, 721 is an intake fan, 722
Is a conveyance fan that sucks the recording paper of the separation conveyance unit 132.

Further, 723 is each sensor of the sorter 300, 724 is a drive motor for rotationally driving each roller of the sorter 300, and 725 is each bin 301a of the sorter 300.
Solenoids for switching the recording paper entry to ˜301x, 726 solenoids of the double-sided reversing unit 400,
727 is a clutch of the double-sided reversing unit 400, 728
Is a jogger motor for aligning sheets of the double-sided reversing unit 400, 729 is each sensor of the double-sided reversing unit 400, 730 is each sensor of the ADF 200, and 731 is AD.
F200 solenoids, 732 is a motor that rotationally drives each transport roller of the ADF 200, and 733 is an ADF2
A switch for detecting the setting state of 00 and a switch for switching the paper thickness of the document, and 734 is a display unit for displaying the number of documents of the ADF 200, a jam condition, and the like.

Further, 735 is a scanner motor for scanning and driving the scanner unit, 736 is a rotary encoder connected to the drive shaft of the scanner motor 735, 737 is a lamp control circuit for controlling the lighting of the light source 102, and 738 is a sub-scanning drive mechanism. HP sensor for detecting the reference position of 739, 739
Is ADFSOL (solenoid), 740 is APSSOL
(Solenoid), 741 is a fluorescent lamp heater and a thermistor for temperature control, 742 is a charging charger 123, a separation charger 124, and a developing bias electrode (not shown).
It is a high-voltage power supply that applies high-voltage power to.

Further, 802 is an image preprocessor (IPP) having functions of shading correction, black level correction and light amount correction, and 803 is MTF correction function (spatial frequency high range emphasis), speed conversion function (magnification), γ conversion function. , An image processing unit (IPU) having a data depth conversion function (8 bit / 4 bit / 1 bit conversion), a memory device (MEM) 804 for taking in the output of the IPU 803,
An external storage device 805 inputs / outputs data to / from the memory device 804.

8 and 9 are block diagrams of the electrical equipment control section of the digital copying machine according to this embodiment. The two diagrams are obtained by dividing one block diagram, and the two diagrams are connected to form one overall block diagram.

The control unit of the color copying machine has two Cs.
It has a PU, the CPU (a) controls sequence-related control, and the CPU (b) controls operation-related. The CPU (a) and the CPU (b) are connected by a serial interface (RS232C).

First, the sequence control will be described.
The CPU (a) (hereinafter, referred to as a sequence) controls the timing of the recording paper conveyance, and as shown in FIG. 9, a paper size sensor, a sensor related to the paper conveyance such as discharge detection and registration detection, A double-sided control plate 704, a high voltage power supply 742, a relay driver, a solenoid driver, a motor driver, a sorter control plate 703, an optical writing unit 743, etc. are connected.

Regarding the sensor, a paper size sensor for detecting the size and direction (direction) of the recording paper loaded in the paper feed cassette and outputting an electric signal according to the detection result, resist detection, paper discharge detection, etc. Signals are input from a sensor related to recording paper conveyance, a sensor that detects the presence or absence of a supply such as an oil end and a toner end, and a sensor that detects a machine abnormality such as a door open or a fuse blown.

Input / output signals of the double-sided control plate 704 include a motor for aligning the width of the recording paper, a paper feed clutch, a solenoid for changing the conveyance path, a paper presence sensor, and a side fence for aligning the recording paper width. There are home position sensors, paper transport sensors, and so on.

The drivers include a paper feed clutch, a registration clutch, a counter, a motor, a toner replenishing solenoid, a power relay, and a fixing heater.

The sequence and the sorter control plate 703 are connected by a serial interface, and the sorter control plate 703 conveys the recording paper at a predetermined timing according to a signal from the sequence and discharges the recording paper to the bins 301a to 301x. There is.

The fixing temperature, the photo sensor input (P sensor input), the monitor input of the semiconductor laser 112, and the reference voltage of the semiconductor laser 112 are input to the analog input section (see FIG. 8). The fixing temperature is controlled on / off by an input from a thermistor in the fixing unit so that the temperature of the fixing unit becomes constant. As for the photosensor input, a photosensor pattern created at a predetermined timing is input by a phototransistor, and a toner replenishing clutch is turned on / off to control the toner density.

As a mechanism for adjusting the power of the semiconductor laser 112 to be constant, an A / D converter and an analog input section of a CPU are used. This is a preset reference voltage (the output voltage of the semiconductor laser is 3 mW
Is set so that the semiconductor laser 112
It is controlled so that the monitor voltage when the lights up is the same.

The image processing substrate 110 generates timing signals for masking / trimming of image data, erasing, photosensor pattern of density sensor, etc., and outputs a video signal to the semiconductor laser 112. The gate array synchronizes the image data continuously transmitted in 2-bit parallel from the scanner unit with the synchronization signal PMSYNC from the optical writing unit 743, and further converts the image data into a 1-bit serial signal in synchronization with the image writing position signal RGATE. And outputs it to the image processing board 110.

Next, operation-related control will be described below. The main CPU (b) controls a plurality of serial ports and a calendar IC. In addition to the sequence of sequence control being connected to the plurality of serial ports, an operation unit 850, a scanner control circuit 800, an application circuit 706, an editor, etc. are connected.

In the operation unit 850, the key input information by the operator is serially transmitted to the main CPU (b), and the display unit is turned on by the serial reception from the main CPU (b). In the scanner control circuit 800, the scanner motor 73
Drive control, image processing, and serial transmission processing of image reading information to the main CPU (b);
Interface processing between the DF 200 and the CPU (b) is performed.

The application circuit 706 exchanges preset information through an interface with an external device (facsimile device, printer, etc.).
In addition, the editor is image editing data (masking, trimming, image shift, etc.) input from the operation unit 850.
Is serially transmitted to the main CPU (b) to input the processing content of image editing. The calendar IC reads the stored date and time by the main CPU (b) at any time,
The current time is displayed on the display unit of the operation unit 850, timer control by setting the on time and the off time of the copying machine, and the like are executed.

FIG. 10 is a block diagram showing the scanner section (see FIG. 7) in the digital copying machine according to this embodiment. In the figure, 801 is a timing control circuit that outputs each signal based on an instruction from the scanner control circuit 800, 802a is a signal processing circuit that performs image signal amplification and light amount correction processing, and 802b is analog data converted to digital data. An A / D converter 802c is a shading correction circuit for correcting distortion of image data.

The image reading operation of the scanner section configured as described above will be described. The scanner control circuit 800 uses the lamp control circuit 73 based on an instruction from the main CPU (b).
7, timing control circuit 801, IPU 803, and
The scanner motor 735 is controlled. Lamp control circuit 73
7 is a light source 1 based on an instruction from the scanner control circuit 800.
ON / OFF of 02 and light amount control are performed.

Further, the timing control circuit 801 outputs each signal based on the instruction from the scanner control circuit 800. That is, when the reading of the document starts, the CCD
A transfer signal for transferring data for one line to the shift register and a shift clock pulse for outputting the data in the shift register bit by bit are output to the image sensor 109. Further, a pixel synchronization clock pulse CLK and a main scanning synchronization pulse LSY are supplied to an image reproduction system control unit (not shown).
The NC and the main scanning effective period signal LGATE are output.

This pixel synchronizing clock pulse CLK is C
The signal is almost the same as the shift clock pulse input to the CD image sensor 109. In addition, the main scanning synchronization pulse LS
YNC is almost the same signal as the main scanning sync signal PMSYNC output from the sync sensor of the optical writing unit 743, but is output in response to the pixel sync clock pulse CLK. The main scanning effective period signal LGATE is output data DATA0 to DATA0.
It becomes H level at the timing when DATA7 is regarded as valid data. In this case, the CCD image pickup device 109
Outputs 4800 bits of valid data per line.

Further, the scanner control circuit 800 has a main C
Upon receiving a reading start instruction from PU (b), the light source 102 is turned on, the scanner motor 735 is started to be driven, and the timing control circuit 801 is controlled to start reading by the CCD image pickup device 109. In addition, the sub-scanning effective period signal FGA
Set TE to H level. The sub-scanning effective period signal FGATE becomes L-level after the time required to scan the maximum reading length (in this case, the size in the longitudinal direction of A size) in the sub-scanning direction after being set to H level.

The analog signal output from the CCD image pickup device 109 is the signal processing circuit 8 in the IPP 802.
Amplification processing and light amount correction by 02a, A / D converter 80
It is converted into a digital multilevel signal by 2b. The converted image signal is subjected to distortion correction by the shading correction circuit 802c and input to the next IPU 803.

FIG. 11 is a block diagram showing details of the IPU 803 according to this embodiment. In the figure, reference numeral 901 denotes an MTF correction unit for correcting blurring or deterioration of an image signal, and 902.
Reference numeral 903 denotes a scaling processing unit that electrically scales the image signal based on a designated scaling factor, 903 a γ conversion unit that corrects the input / output characteristics of the image signal to be optimum for the characteristics of the image forming process,
Reference numeral 904 denotes a data depth switching mechanism section including a 4-bit conversion circuit 905, a binarization circuit 906, a dither circuit 907, a changeover switch (SW1) 908, and a changeover switch (SW2) 909.

The data processing operation of the IPU 803 configured as above will be described. The image signal input from the IPP 802 is high-frequency emphasized by the MTF correction unit 901. Next, the scaling processing unit 902 performs electrical scaling to a predetermined magnification, and the γ conversion unit 903 optimizes the input / output characteristics of the image signal with respect to the image forming process characteristics. γ conversion unit 90
The image signal output from the data 3 is a data depth switching mechanism unit 9
It is input to 04 and converted into a predetermined quantization level.

This data depth switching mechanism section 904 has 4 bi
The t conversion circuit 905 outputs 4 bit DATA.
The binarization circuit 906 converts the inputted 8-bit multi-valued data into binary data by a preset fixed threshold value and outputs 1-bit DATA. Dither circuit 907 is 1
A halftone image is displayed by bitDATA. At this time, the changeover switch (SW2) 909 selects and outputs the output of the binarization circuit 906 or the dither circuit 907. Then, the changeover switch (SW1) 908 is used for these three data (8 bit DATA, 4 bit DATA, 1 bit).
DATA0) and select DATA0
Outputs (least significant bit) to DATA7 (most significant bit). The changeover switch (SW1) 908 and the changeover switch (SW2) 909 are changed over by a signal from the scanner control circuit 800, whereby the quantization level of the image signal can be changed. This IPU
The output data format of 803 is shown in FIG.

FIG. 13 shows the IPU 80 in this embodiment.
FIG. 3 is a block diagram showing a memory system including a MEM 804 and a multiplexer. In the figure, reference numerals 810 to 812 denote multiplexers (MUX1), (MUX) for selecting and switching a plurality of input data.
2) and (MUX3), EXTIN in the figure indicates an image data input signal from the outside, and EXTOUT indicates an output signal to the outside.

The operation of the memory system configured as above will be described. For example, when outputting a copy in which the parameters of a plurality of IPUs 803 are changed by one exposure scan of the scanner unit, first, the multiplexer (MUX1) 810 is set to A and the multiplexer (MUX) is set at the time of scanner scanning.
2) 811 is set to B and multiplexer (MUX3) 812 is set to A, and the first copy is performed. The raw data at this time is sent to the ME via the multiplexer (MUX2) 811.
Input to M804.

Next, the second and subsequent sheets are multiplexers (MUs).
X1) 810 is set to B, the data from the MEM 804 is input to the IPU 803, and the multiplexer (MUX
3) Output to the scanner control circuit 800 via 812. At this time, the parameters of the IPU 803 are changed every time copying is performed. When holding compact data such as 1-bit DATA, a multiplexer (MU)
X2) 811 is set to A, and the output of the IPU 803 is taken into the MEM 804. At this time, the optical writing unit 743 switches to the binary data (1 bit) mode and executes the copying process.

FIG. 14 is an explanatory diagram showing the flow of image signals according to the present embodiment, and shows the flow of data by the processing described in FIG. In this way IPU803
MEM8 for both raw and processed data
It is possible to take in 04. This makes M
By inputting raw data stored in the EM 804 into the IPU 803, a plurality of IPU 803 can be obtained by one scan.
You can make a copy with changed parameters. Further, for example, when handling compact image data such as 1-bit DATA, the output of the IPU 803 is set to the MEM80.
I am trying to incorporate it in 4.

FIG. 15 shows the M used in this embodiment.
The block diagram of the structure of EM804 is shown and it is the structure which connected the pixel process unit (PPU) to the memory unit 804c. In the figure, 1801 is a logical operation between image data (for example, AND, OR, EOR, N
Pixel process unit (PP) that performs OT
U) and 1802 are image process units (IPU)
803 and Pixel Process Unit (PPU) 1801
A multiplexer (MUX6) 1803 for selecting and switching data input from is a multiplexer (MUX7) 1803 for selecting and switching data input from the pixel process unit (PPU) 1801 and the memory unit 804c.

In the above configuration, the pixel control unit (PPU) 1801 logically operates the memory output data and the input data to perform the scanner control circuit 800.
Output to. Also, memory output and input data (eg,
The data from the scanner unit) can be logically calculated and stored again in the memory unit 804c. The input data to the memory unit 804c which is the output destination and the scanner control circuit 800 is switched by the multiplexer (MUX6) 1802 and the multiplexer (MU).
X7) 1803. Such a function is generally used for image composition processing, for example, image composition processing such as overlaying overlay on scanner data.

FIG. 16 is a block diagram showing an example of the internal structure of the memory unit 804c. In the figure, 1
Reference numeral 601 is an input data width converter for processing input data such as image data (including image data whose quantization level has been changed), 1602 is a memory block for storing packed image data, 1603 is a memory block 16
An output data width converter for processing and outputting the image data stored in 02, 1604 is an input data width converter 16
A direct memory controller (DMC1) for writing / reading data at a predetermined address of the memory block 1602 corresponding to the number of data packed by 01 and the memory data width, and 1605 is an output data width converter 1603.
A direct memory controller (DM) that performs a data write / read operation to a predetermined address of the memory block 1602 corresponding to the data packed by the memory and the memory data width.
C2).

Memory unit 8 configured as described above
In 04c, an input data width converter 1601 and an output data width converter 1603 are arranged on the input side and the output side of the memory block 1602, respectively. In the present embodiment, the data width of the storage area of the memory block 1602 is 16 bits, and the input data width converter 1601 packs the image data according to the three quantization levels changed by the IPU 803 (see FIG. 17). ), Output data width converter 16
03 unpacks the image data. The direct memory controller (DMC1) 1604 controls writing of image data to a predetermined address of the memory block 1602 in accordance with the number of data packed by the input data width converter 1601 and the data width of the storage area. In addition, the direct memory controller (DMC2) 160
Reference numeral 5 controls the reading of image data from the memory block 1602 by the output data converter 1603.

Next, regarding the processing operation for the image data amount stored in the memory block 1602, by mounting a large sorter and performing continuous copying,
A case where a large number of recording sheets exist in the machine will be described as an example. Here, the storage capacity of the memory block 1602 in this embodiment is set to correspond to the number of recording sheets that may exist in the machine in a general case.

The memory block 1602 stores all the image data formed on the recording paper inside the machine, and when one recording paper is ejected out of the machine, the main CPU (b) causes the scanner control circuit 800 to operate. A predetermined signal is output to. When the scanner control circuit 800 receives this signal, it outputs a predetermined control signal to the direct memory controller (DMC1) 1604 and the direct memory controller (DMC2) 1605. The direct memory controller (DMC1) 1604 makes the image data of the recording paper discharged outside the machine unnecessary by this control signal,
For example, in the memory block 1602, when there is no extra storage area, new image data is overlaid on the area where the image data of the discharged recording paper was stored.

When the memory capacity in the memory block 1602 becomes low, the direct memory controller (DMC1) 1604 outputs a signal to that effect to the scanner control circuit 800, and the scanner control circuit 80
For 0, the IPU 803 changes the quantization level of the image data (see FIG. 11). As a result, the image data of the recording paper existing in the machine is stored in the memory block 160
2 can be stored. Here, the remaining storage capacity in the memory block 1602 is determined by the number of recording sheets existing in the machine or the amount of image data actually stored, but it may be determined by both conditions. Good.

When the storage capacity in the memory block 1602 is further reduced (in the present embodiment, there is no storage capacity for storing the image data of one original document), the main CPU (b) is a recording paper cassette. 128
By temporarily suspending the removal from the a, 128b, and 128c, it is possible to reduce the number of recording sheets existing in the machine and store new image data in the memory block 1602. In this case, the recording paper existing in the apparatus may be reduced by increasing the document conveyance interval time by the ADF 200. As a result, even if the recording paper is jammed, the image data of the jammed recording paper is stored in the memory block 1602. Therefore, the original corresponding to the jammed recording paper is again placed on the contact glass 106. There is no need to place it, and jam handling can be made extremely easy.

Next, the operation of reading the image data of the jammed recording paper from the memory block 1602 will be described. When the recording paper is jammed, the main CPU (b) determines the jammed recording paper by the sensor arranged in the machine and causes the scanner control circuit 800 to output a control signal to the direct memory controller (DMC2) 1605. . When the control signal is input, the direct memory controller (DMC2) 1605 controls the output data width converter 1603 to read the image data of the jammed recording paper from the memory block 1602.

FIG. 17 shows the memory block 1 shown in FIG.
6 is an explanatory diagram showing a format of image data stored in 602. FIG. (A) Type 1 shows 1-bit data, (b) Type 2 shows 4-bit data, and (c) Type 3 shows 8-bit data. It should be noted that the normal transfer rate of image data from the scanner or the transfer rate of image data to the scanner control circuit 800 is 8 bits because the period of one pixel is fixed in the apparatus.
It is constant regardless of data, 4-bit data, and 1-bit data.

In this embodiment, the MBS (Most Significant Bi) of eight data lines is used.
(t: the most significant bit of data) is defined as 1-bit data, 4-bit data, 8-bit data and MBS justification. This data is stored in the memory block 1602.
The blocks to be packed and unpacked to the data width (16 bits) of the input data width converter 1601 and the output data width converter 1603 can use the memory corresponding to the data depth by performing the packing process.
Can be effectively used.

FIG. 18 is a block diagram showing the configuration of the external storage device 805 which executes the image data saving process.
In this embodiment, the image data can be stored in the external storage device 805 when the image data of a large number of originals is desired to be stored in the copy mode or the like.
In the figure, 805a is an interface (I / F) that controls input / output of image data, 805b is a file controller (FC) that controls a floppy disk controller (FDC) 805e, and a hard disk controller (HDC) 805c, and 805c is A hard disk controller (HDC) that controls writing / reading of a hard disk (HDD) 805d, and a writing / reading 805d.
A readable hard disk (HDD), 805e is a floppy disk controller (FDC) that controls a floppy disk driver (FDD) 805f, 805f is a floppy disk driver (FDD) that drives a floppy disk (FD) as a storage medium, and 805g is A line drawer (LD) that controls the interface (I / F) 805a.

The operation of saving the image data in the external storage device 805 in the above configuration will be described. When the image data is stored in the floppy disk (FD), it is output from the EXTOUT shown in FIG. 13 to the floppy disk controller (FDC) 805e controlled by the file controller (FC) 805b via the interface (I / F) 805a. , The floppy disk driver (FDD) 805f stores the data on the floppy disk (FD). The hard disk controller (HDC) 805c is a file controller (F
C) A hard disk (HD
D) Write / read on 805d. It should be noted that the hard disk (HDD) 805d stores format data and overlay data for general use, and can be used as needed.

Next, another embodiment of the memory device (MEM) 804 will be described with reference to FIGS. The operation based on the image data amount stored in the memory unit 804c is described in the above-mentioned MEM80.
4 (see FIG. 15).

FIG. 19 shows the above memory device (MEM) 80.
4 is a block diagram showing an example of the internal configuration of FIG. In the figure, 804a is a COMP (compressor) that performs data compression processing, 804b is a multiplexer (MUX4) that selects and switches data input from the IPU 803 and COMP 804c, and 804c is CO in addition to image data.
A memory unit for storing compressed data processed by the MP 804a, and an EXP for decompressing data 804d.
(Expander), 804e is a memory unit 804c and EX
Multiplexer (MUX5) for selecting and switching data input from P804d, 813 is COMP804
It is an error detector which monitors the error signal of a and EXP804d.

The MEM 804 configured as described above is
The COMP 804a is arranged in front of the memory unit 804c, the EXP 804d is arranged after the memory unit 804c, and the multiplexer (MUX4) 804b,
By providing the multiplexer (MUX5) 804e connected to the memory unit 804c, the image data and the compressed data can be selectively stored. That is, when the image data is stored in the memory unit 804c, the multiplexer (MUX4) 804b and the multiplexer (MUX5) 804e are set to A, respectively.
When storing the data processed by the COMP 804a in the memory unit 804c, a multiplexer (MU) is used.
X4) 804b and multiplexer (MUX5) 804e
To B respectively. In the above structure, CO
The MP804a performs memory processing according to the scanning speed of the scanner unit, and the EXP804d uses the scanner control circuit 8
The processing is executed according to the transfer speed to 00. When storing the compressed data in the memory block 1602, the input data width converter 1601 stores the compressed data in the memory block 1602 without performing processing on the compressed data.

FIG. 20 shows image data compression and
FIG. 16 is a block diagram of a configuration example of a memory device (MEM) 804 that enables recovery when the decompression processing speed is not in time. This MEM 804 is effective when handling a binary image signal (the image data is often represented by a binary image signal), and in FIG.
Is a memory management unit (MMU) for controlling the memory by simultaneously inputting / outputting two input data and one output data to / from the memory unit 804c, and 815 selects data input from the memory unit 804c and the EXP804d. It is a multiplexer (MUX8) for switching.

In the above configuration, the memory unit 80
Simultaneously with scanning with the scanner, data and image data compressed by the COMP 804a are input to the memory unit 804c at 4c. The data input to the memory unit 804c is stored in different memory areas, and the compressed data is input to the EXP 804d as it is for decompression processing. Memory unit 80 for all data for one page
If the processing time by COMP 804a and EXP 804d is in time until the input to 4c is completed and the processing is completed normally, the memory area of the compressed data is left,
Release the image data area.

Here, the error detector 813 causes the COM
When an error signal from P804a or EXP804d is detected, the data area of the compressed data is immediately canceled and the image data is adopted. COMP8
04a and EXP804d verification processing,
High-speed and reliable data processing and effective use of the memory area can be realized.

As described above, the memory management unit (M
The MU) 814 enables dynamic allocation of the memory area, but the same processing can be performed by disposing two memory units for image data and compressed data as another method. Such a configuration is effective when used for applications such as electronic sorting, in which multiple pages are stored and the conditions that satisfy both the number of stored pages and the printing speed, such as outputting to a printer in real time, must be satisfied. Target.

In the present invention, the quantization level of the image data is automatically changed by the remaining storage area in which the image data can be stored in the memory. For example, when the storage area is low, the operation panel The fact may be displayed on the display so that the quantization level can be arbitrarily selected. Further, the quantization level of the image data stored in the memory may be selected from the beginning.

[0090]

As is apparent from the above, according to the present invention, image processing means for performing predetermined image processing such as shading correction and MTF correction on image data input through the input means, and an image by the image processing means. In an image forming apparatus provided with a storage unit for storing processed image data, the corresponding image data is held in the storage unit until the image forming operation is normally completed, and the image forming operation is not normally completed. In this case, since the image forming apparatus is provided with the control unit that executes the image forming operation using the image data stored in the storage unit, the memory can be effectively used to operate the apparatus without increasing the cost of the memory. It is possible to improve efficiency.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a schematic configuration of a digital copying machine which is an image forming apparatus of this embodiment.

FIG. 2 is an explanatory diagram showing a configuration of a copying machine main body.

FIG. 3 is a plan view of a writing unit.

FIG. 4 is an explanatory diagram showing a configuration of an ADF.

FIG. 5 is an explanatory diagram showing a configuration of a sorter.

FIG. 6 is an explanatory diagram showing a configuration of a double-sided reversing unit.

FIG. 7 is a block diagram showing the overall configuration of a digital copying machine.

FIG. 8 is a circuit diagram showing an electrical equipment control unit in the digital copying machine.

FIG. 9 is a circuit diagram showing an electrical equipment control unit in the digital copying machine.

FIG. 10 is a block diagram showing an image reading operation of the scanner of the digital copying machine.

FIG. 11 is a block diagram showing details of an image process unit.

FIG. 12 is an explanatory diagram showing an output data format of an image process unit.

FIG. 13 is a block diagram showing a memory system according to the present invention.

FIG. 14 is an explanatory diagram showing a flow of an image signal according to the present invention.

FIG. 15 is a block diagram showing a configuration of a memory device according to the present invention.

FIG. 16 is a block diagram showing an internal configuration of a memory unit.

FIG. 17 is an explanatory diagram showing a format of image data stored in a memory block.

FIG. 18 is a block diagram showing a configuration of an external storage device.

FIG. 19 is a block diagram showing an example of an internal configuration of a memory device.

FIG. 20 is a block diagram showing the configuration of a memory device that enables recovery when the processing speed of compression and expansion of image data is not in time.

FIG. 21 is a block diagram showing a flow of conventional image data processing.

[Explanation of symbols]

110 image processing board 701 main control board 800 scanner control circuit 802 image preprocessor 803 image process unit 804 memory device 804c memory unit 904 data depth switching mechanism section 905 4-bit conversion circuit 906 binarization circuit 907 dither circuit 908 changeover switch (SW1) 909 Switch (SW2) 1601 Input data width conversion unit 1602 Memory block 1603 Output data width conversion unit 1604 Direct memory controller (DMC1) 1605 Direct memory controller (DMC2)

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoshikazu Inoue             1-3-3 Nakamagome, Ota-ku, Tokyo Stocks             Company Ricoh

Claims (5)

[Claims] 1. An image processing unit for performing predetermined image processing such as shading correction and MTF correction on image data input through an input unit, and a storage unit for storing image data image-processed by the image processing unit. In the provided image forming apparatus, the corresponding image data is held in the storage unit until the image forming operation is normally completed, and when the image forming operation is not normally completed, the image data is stored in the storage unit. An image forming apparatus comprising: a control unit that executes an image forming operation using existing image data. 2. The image processing means automatically stores the image data when the number of originals of the image data stored in the storage means or the amount of image data stored in the storage means exceeds a predetermined value. The image forming apparatus according to claim 1, wherein the quantization level is changed. 3. The image forming apparatus according to claim 1, wherein the image processing unit changes the quantization level by using a quantum number switching circuit. 4. Only valid data is extracted from the image data based on the quantization level of the image data,
Data width conversion means for converting the image data into an effective data width and storing the image data in the storage means in the storage means as a storage unit based on the data width of the storage area of the storage means. The image forming apparatus according to claim 1, further comprising: 5. When the image data stored in the storage means exceeds the storage capacity of the storage means, or when a predetermined amount or more of image data is stored in the storage capacity, the recording paper is automatically recorded. The image forming apparatus according to any one of claims 1, 2, 3, and 4, further comprising a paper feed control means for limiting paper feed.