JPH08265583A - Color image forming device - Google Patents

Abstract

PURPOSE: To provide the color image forming device which arbitrarily selects the performance for the copy speed or the black character quality by providing a control means which changes the image formation order of black in accordance with the discrimination result of an image color discrimination means. CONSTITUTION: An image reader 250 of a scanner module 200 inputs picture data separated to plural color components. A color document automatic detection circuit 320 discriminates whether inputted picture data is a black-and-white picture or a color picture. A copy processing part CP of an application processor 650 of a system control module 600 discriminates whether inputted picture data is a black-and-white picture or a color picture and the image of black is first formed when the black monochromatic recording/color recording selection function based on discrimination of the circuit 320 is turned on; but it controls image formation of the printer module so that the image of back is formed in the second or following operation when this selection function is turned off and image formation in plural colors including black is selected. Consequently, the performance advantageous to the picture quality or the operability can be selected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image forming apparatus which forms a plurality of color images including black (K) based on color image data composed of a plurality of color components. Specifically, it is applied to, for example, a digital color copying machine, a color facsimile, a color printer and the like.

[0002]

2. Description of the Related Art For example, in a digital color copying machine, the originals to be copied are red (R), green (G) and blue.
(B) Color-separated and read, and based on this image data,
A color image is reproduced using color materials of yellow (Y), magenta (M), cyan (C), and black (K). One of such color image forming apparatuses is Japanese Patent Laid-Open No. 63-10727.
No. 4 is disclosed. Here, the process of winding the recording paper around the transfer drum, forming images corresponding to the color materials of a plurality of colors used for recording on the photosensitive drum in a frame-sequential manner, and transferring to the recording paper is repeated only for the type of the color material used . That is, YMC
When a color image is reproduced with four colors of K, the image forming process is repeated four times.

However, when the original to be copied is composed of only black and white, such as a document original often found in offices, in principle, only K can be used for reproduction. However, if the operator discriminates the original color one by one and copies only with K,
It is troublesome to instruct the device whether to make a copy with four colors of YMCK. Further, an automatic document feeder (ADF: Automatic Ddo)
In the case of a copier with a cument feeder, when copying a mixed black-and-white and color original, it is necessary to classify the original into a black-and-white original and a color original in advance and set them in the ADF in two steps.

The above-mentioned color image forming apparatus disclosed in Japanese Patent Laid-Open No. 63-107274, as a measure against this problem, performs a test scan (pre-scan) on an original document before image formation to determine whether the original document is only a black and white image. Is performed, and if it is a black-and-white original, the sequence of copying only with K is executed. If it is a color original, a sequence for copying in four colors of YMCK is executed. However, this method has a problem that the time required for copying becomes long because it is necessary to scan the document once more in addition to the original image formation.

In Japanese Unexamined Patent Publication No. 04-156183, as a measure for remedying the problem of the method in Japanese Unexamined Patent Publication No. 63-107274, the K-color image formation is performed at the same time as the first original scanning, and the original colors are identified. When the original document is identified as a black-and-white original document at the end of the first scanning, the copy sequence is terminated with only K, and when the original document is identified as a color original document, the image forming sequence of color components is continuously executed. In this method, since the document is scanned by the number of recording colors, the time required for copying does not become long.

By the way, in the image forming apparatus using the electrophotographic process as described above, when an image is formed in a plurality of colors, the toner image formed on the recording paper at the first time is subjected to the image forming operation at the second time and thereafter by the image forming operation. Will re-contact the drum. At this time, due to the adhesive force acting between the toner and the photoconductor, the toner transferred to the recording paper is reverse-transferred to the photoconductor, or the electric field generated by the effect of the charged photoconductor causes the toner on the recording paper. The toner is scattered, and the image quality is deteriorated such that the lines are blurred or blurred particularly in the character and line drawing image portions. This deterioration is greater as the image forming order is faster, and when K is imaged first, in a document in which black characters and color images are mixed in one document, the quality of black characters, which is particularly required for resolution, is inferior. There is.

[0007]

Conventionally, in a color image recording apparatus having a function of automatically identifying the original color, even if the full-color image formation is forcibly designated in preference to this function, the image formation is completed. The sequence is fixed, and the user has to sacrifice the copy speed in the apparatus for performing the pre-scanning of the document color identification and the image quality in the apparatus for forming the first color image as the specification of the apparatus.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a color image forming apparatus which allows a user to select a desired performance such as copy speed, black character quality, or the like.

[0009]

A first invention is a color image forming apparatus for forming a color image with a plurality of colors of a first number (4) including black (K) by using an electrophotographic process.
Means (250) for inputting image data color-separated into a plurality of color components of the second number (3); Image color identification means (32) for identifying whether the input image data includes a monochrome image or a color image
0); ON / OFF of the function (ACS) of the image color identification means (320)
And a function of the image color identification means (320) (AC
When S) is ON, black (K) is imaged first, and when OFF is selected with multiple colors including black (K), black (K) is selected.
The control means (600) for making the image forming order of the second or later is characterized.

A second invention is a color image forming apparatus for forming a color image with a plurality of colors of a first number (4) including black (K) using an electrophotographic process, and a second number (3). A method for inputting image data that has been separated into multiple color components (2
50); image color identification means (320) for identifying whether the input image data includes a monochrome image or a color image; means for switching the timing at which the image color identification means (320) operates
0,650); and when the image color identification means (320) is made to function at the first timing, black (K) is imaged first, and when it is made to function at the second timing, black (K). Is provided for the second and subsequent images.

In order to facilitate understanding, the symbols or corresponding matters of the corresponding elements of the embodiments described later with reference to the drawings are added in parentheses for reference.

[0012]

In the first aspect of the present invention, when the image color identification function (ACS) is ON, the image color identification means (320) separates the input image data into a plurality of (3) color components into a monochrome image. Or the color image is included, the control means (600) sets K as the first image formation, and when the image color identification function is OFF and image formation in a plurality of colors including K is selected, the control means is selected. (600) controls the image formation of K so that it is second or later.

In the second aspect of the invention, the switching means (800, 650) switches the timing at which the image color identification means (320) functions,
When the control means (600) causes the image color identification means (320) for identifying whether the image data color-separated into the plurality of (3) color components includes a monochrome image or a color image to function at the first timing, When K is imaged first and the image color identification means (320) is made to function at the second timing, K is controlled to be imaged after the second.

[0014]

【Example】

—Outline of Outline— The color image forming apparatus of this embodiment is composed of three modules, a scanner module 200, a printer module 400, and a system control module 600. In some cases, an integral connection of the three is not necessary. 1 and 2 show five examples (a) to (e) of usage modes. In these drawings, squares are functional blocks,
The HOST is an external computer device or a facsimile machine (external module), and a thick line 20 between the modules.
Reference numerals 0S and 400S represent transmission lines for control signals and image signals connecting between modules, specifically SCSI cables.

FIG. 1A shows a scanner module 20.
0 shows a usage mode in which 0 is connected to the HOST as a so-called scanner device, and FIG. 1B shows a usage mode in which the printer module is connected to the HOST as a so-called printer.

FIG. 1 (c) shows a mode of use as a general copying machine, one scanner module 2 each.
00, a printer module 400, and a system control module 600 are connected. Here, the system control module 600 is a copy processing CP for integrally controlling the above-mentioned two modules 200 and 400 to achieve a copy function.
(CP in 650 of FIG. 4) is incorporated.

FIG. 2D shows a usage mode of the triple reading copying machine. In this, the first scanner module
The module 200-1, the second scanner module 200-2, the third scanner module 200-3, the printer module 400 and the system control module 600 are connected. Here, for example, the first scanner module 20
0-1 is a general A3 size scanner, the second scanner module 200-2 is a large size scanner such as A1 size, and the third scanner module 200-3 is a color scanner. There are various advantages compared to installing dedicated copying machines. Further, the combination and the number of these can be arbitrarily changed according to the usage frequency. Here, the system control module 600 integrally controls the above-mentioned four modules 200-1 to 3400 to achieve a copying function, so that a duplicate reading process CP2 (indicated by 650 in FIG. 4). One function of CP) is incorporated.

Although not shown, a plurality of printer modules 400 can be similarly connected. At this time, the system control module 600 controls the other modules in an integrated manner to achieve the copying function by the continuous recording copying CP3 (one function of CP in 650 of FIG. 4). Is incorporated. In addition, in the multi-row system, up to six scanner modules 200 and printer modules 400 can be connected together.

FIG. 2E shows the scanner module 20.
0, printer module 400, system control module
It is a copier with copying, facsimile, and printer functions, which is composed of the printer 600. The system control module 600 has a communication line 6 for connecting a host computer.
80PC and communication unit 680P, print processing PR (PR in 650 in FIG. 4) for converting the print data received by the communication unit 680P into the raster description data, and the public line The communication unit 680F for connecting to the 680FC and the reception data of a predetermined compression format received by the communication unit 680F are received.
A color facsimile processing FX (FX in 650 in FIG. 4) for expanding the data and compressing the original image data read by the scanner module 200 into a predetermined format is incorporated.

-Structure of Each Module-In addition to the structure of the above-mentioned three modules 200, 400 and 600, the module connection when the system is structured as a copying machine with a facsimile and a printer function (for example, (e in FIG. 2) )) In addition to an automatic document feeder 280, a film projector 290, a multi-stage sheet feeder 480 and a sorter 490, which are additional modules (FIG. 3 + FIG. 4 + FIG. 5: electrical system outline, FIG. 6 + FIG. 7 + FIG. 8: Mechanism outline) will be described. 3, FIG. 4, and FIG. 5 are block diagrams of an electric system of one embodiment, which should be originally shown in one drawing, divided into three parts. In the figure, the signal lines with the same symbols are connected to each other as shown in FIGS.
By connecting the drawings in FIG. 5 and FIG. 5, a block diagram of the electric system of the entire embodiment is shown. Similarly, FIGS. 6, 7, and 8 also show a mechanism schematic diagram of one embodiment, which should be originally shown in one drawing, divided into three parts. The printer 400 shown in FIG. 7 is placed on the multi-stage paper feeder 480 shown in FIG.
By placing the system control 600 on top of 00, and placing the scanner 200 on FIG. 6 on top of this system control 600, a schematic diagram of the entire mechanism of one embodiment appears.

Scanner Module 200 (FIGS. 3 and 6)
Overview: The scanner module 200 includes an image reader (202) that reads at least an original image by dividing it into pixels.
˜207, 250), a scanner controller 230 including the first communication unit SCSI, and a power supply circuit 201. Basic image processing circuit 300 and extended image processing circuit 3
50 is added as needed. The image readers (202 to 207, 250) include a color image pickup device 2 for converting a color photographed image into a color component signal.
07, analog / digital converter for converting each color component signal into digital data (hereinafter referred to as A / D converter)
252 etc. are included.

Printer module 400 (FIGS. 5 and 7)
Outline: The printer module 400 includes a paper feed table 412.
Image forming mechanism 400 img for forming and discharging a visible image on the recording medium 190 (A to C) fed from B
A printer controller 430 including a communication unit SCSI of
There is a power supply circuit 401. Image forming mechanism 400i
mg is an electrophotographic image forming device such as an electrophotographic photosensitive member 414, a charger 419, a laser exposure device 441, a developing device 420, a first transfer device 414, an intermediate transfer member 415, and a second transfer device 427. Equipment is included.

Overview of system control module 600 (FIGS. 4 and 7): The system control module 600 includes a third
There is a system controller 630 which includes a communication unit SCSI of The system controller 630 is a scanner module 2
00 for image reading control, and printer module 400
Control the image formation.

Outline of mechanical combination of modules: These three modules 200, 400, 600 can satisfy the function of the system even if they are mechanically arranged as shown in FIGS. It is as a possible structure. For example, in a copying machine configuration (combination as a copying machine), the scanner module 200 is packed in one unit while the printer module 400 is packed in order to reduce the transport unit weight and simplify the system assembly. The system control module 600 is a printer module 40.
The system control module 600 is fixedly mounted on the upper part of 0 to form an integral structure, which is packed in one box and shipped from the factory.

Further modules 200, 400 and 6
When combining 00, consideration for users such as usability, aesthetic cohesion, space occupation efficiency, or electromagnetic radiation,
It also addresses technical issues such as noise immunity, heat dissipation, and prevention of mechanical resonance. For example, when configuring a copying machine, at least the above-mentioned 3 modules 2
Tables 00, 400 and 600 are combined with a table (not shown) or a multi-stage sheet feeding device 480 (FIG. 8), but these are stacked vertically to increase space occupancy efficiency. Further, the height of the platen of the scanna module 200 is set to 900 mm to 1100 mm to obtain good manuscript placing operability and workability. Also, various buttons are located on the platen surface or slightly below it,
It realizes an accurate human interface.

Three modules 200, 400 and 6
In 00, the projected shapes of the stacking surfaces are made substantially equal to avoid awkwardness, and the upper module is prevented from falling off. From the viewpoints of appearance and compatibility with electromagnetic environment, the number of cables connecting them has been reduced as much as possible, and the terminals have been designed to be close to each other in order to shorten the length. However, the system control module 600 can be constructed extremely compactly in the case where only the copying function is required to be realized, and this can be used as a part of another module (200, 400) or It is easy to install as an additional unit, in this case 2
The above consideration may be made by combining the modules 200 and 400. Next, the configuration and function of each module will be described in detail.

[Scanner Module 200: FIGS. 3, 6 and 9 to 11] In the scanner module 200 shown in FIGS. 3 and 6, the scanner controller 230 is mounted on an electric circuit board. A required voltage is applied from the power supply circuit 201. The power supply circuit 201 includes a power plug 20
A commercial power supply voltage (or a voltage of a separate DC power supply) is applied via 1P. 201SW is a power switch, 2
02 is a platen glass (a glass plate on which a document is placed), 2
02S is the image leading end reference position. 202SH is a shell
White board for correcting the ding, 202B is a bar code board for individual identification (for scanner identification), 208 is a first carriage, 209
Is a second carriage, 203 is a document illumination lamp, 204A,
B and C are first, second and third mirrors respectively, 205 is an image forming lens, 205X is a lens optical axis, 207 is a color image pickup device, 211 is a carriage home sensor, S1 and S2.
Is a SCSI connector on (the electric circuit board of) the scanner controller 230 and having the same shape and the same interface. F1 and F2 are optical fiber connectors for optical communication with an additional device (option) selectively connected to the scanner.

The original image reading circuit 250 is mounted on an electric circuit board, the basic image processing circuit 300 is also mounted on the electric circuit board, and the extended image processing circuit 350 is also mounted on the electric circuit board. These are all housed in the housing of the scanner module 200. [Scanner controller 230:
FIG. 3] In the scanner controller 230, a CPU is a microprocessor, a RAM is a read / write memory, a ROM is a read-only memory, an INT is an interrupt controller, a DV is an input / output circuit for sensors and actuators, and a PF is a PF. Serial communication unit, SYNC is first sync signal generator, X
TL is the first crystal oscillator, DMA is the DMA controller,
FIFO is a first-in first-out memory, SCSI is a first communication unit including a SCSI controller, BUS is a bus, and DC is an image data channel.

[Scan Control Function of Scanner Controller 230:
FIG. 9] The scanner controller 230 is a system control module.
It communicates with the printer 600 or the printer module 400 according to a predetermined protocol, controls the original image reading based on the command, and outputs the original image data. Also, all the means in the scanner module 200 and the document feeder 28
The selective addition device such as 0 is controlled in an integrated manner. By the way, in a general image system in which a scanner and a printer are composed of separate modules, for example, an optical file system, it is common to have some page buffer memory between them. However, in such a configuration, a time difference is inevitably generated between the reading of the original image by the scanner and the image formation by the printer. In copiers, this time difference has the undesirable effect of increasing the so-called first copy time.

Therefore, in this embodiment, the page buffer is omitted to reduce the cost and the scanner module 20 is used.
The method of executing the image reading of 0 and the image formation of the printer module 400 in synchronization, that is, with almost no time difference, is adopted. There are two kinds of technical contents in the synchronization between the image reading and the image formation. One is the coincidence of the cycle, and the other is the coincidence of the phase of the tip of the image. If this synchronization cannot be maintained, problems such as expansion and contraction of the copy image will occur for the former, and for the latter,
It is easy to imagine a situation where the copy image position cannot be reproduced correctly with respect to the recording paper.

Further, in this embodiment, each color (C, M, Y,
K) A frame-sequential image forming type printer module 400 is used, but in a color copying system using this type of printer, the printer module 400 uses each color (C, M,
(Y, K) images are sequentially superimposed and formed, but in order to make the device commercially inexpensive, it is a good idea to omit the page buffer memory. At this time, the scanner module 200
For convenience, it is preferable to perform four scans on a single document and send out one of C, M, Y, and K colors for each original scan. Therefore, in the color sequential scanning of four times, it is important to secure the scanning position accuracy of the original image scanning, that is, to synchronize (the scanning starting point is the same point with respect to the original). If the synchronization is wrong, the color plate will be misaligned, and the correct color image cannot be obtained.

The "synchronization" of this embodiment will be described with reference to FIG. This drawing describes one original scan, and the details of two scans are shown in the upper half of FIG. First, when the SCAN command is received from the system control module 600, the first carriage 208 always reaches the original image leading edge 202S with the optical axis 205X after t5 hours from the reception.
In addition, the sub-scanning speed is Vsub. As a result, the image data is always output after a fixed time t5 from the command reception timing, so that the above-mentioned synchronization regarding the phase is first secured. As a device for this purpose, a sensor 211 (FIG. 6) for detecting a carriage reference position is provided to calibrate the scanning reference position every time, and the sub-scanning movement amount of the stepping motor 210 at one step angle is performed. (The amount of movement of the first carriage 208) is set to 1/16 mm or less.
As a motor drive system, a microstep drive system or the like is used.

Next, for synchronization of the above-mentioned "cycle", one main scanning line is read in synchronization with the pulse train cycle ts1 generated by the first sync signal generator SYNC (FIG. 3), and this is read out as a transmission buffer FIFO. I put it in.
Further, the receiving side of this data, that is, the system control module 600 in this case, sequentially takes out at a cycle substantially the same as the cycle ts1. In the copying mode, the data receiving side is the printer module 400, and the above synchronizing mechanism is maintained. Therefore, no matter how many times the original image is scanned, the original image data will always be obtained after a fixed time from the command reception.
The positional relationship between the paper and the image (registration) is always maintained correctly, no extra buffer memory is required during color copying, color plate registration is maintained, and the copy is quickly output (discharged). ) Will be done. The scanner module 200 is basically the other two modules, that is, the system control module 600 or the printer module.
The SCAN command is received from the file 400.

[Other Functions of Scanner Controller 230: FIG. 1
0, FIG. 11] FIGS. 10 and 11 show a scanner controller 230.
FIG. 3 is a flow chart showing the processing functions of FIG.
This is accomplished by executing the program of the CPU in the scanner controller 230. The execution program is a read-only memory 2
Built in 30 ROM. First, refer to FIG.
When the power is turned on (p201), the CPU executes initialization processing (p202). In this initialization processing, initial parameter setting of various circuit elements, watchdog timer start, initial positioning of the carriage 208, and the like are performed.
Then, a command input from the terminals S1 and S2 is waited, and it is checked whether or not a predetermined time (timeout time) has elapsed while waiting for the command input (p203). When a predetermined time elapses without inputting a command, the power of the image reading circuit 250 is turned off, and the power supply voltage of the image processing circuit 300 and the extended image processing circuit 350 is changed to the data of the register in the circuit element.
Data is lowered to the limit that can be held (p204). This contributes to reduction of power consumption during standby and noise of cooling fan. p205 is generated when the watchdog timer leaves normal execution of the program, and at this time, the failure occurrence notification function p205 notifies the system control module 600 of this. p201 is an interrupt vector when a failure occurs in the image reading circuit 250, the image processing circuit 300, and the extended image processing circuit 350, and p211 identifies the failure portion,
The factor is divided, and p212 notifies the system control module 600 of this. p213 is, for example, motor 2
When 10 is overheated, a fail-safe treatment is performed to avoid the risk of fire.

P220 is an interrupt vector when information is input to the SCSI terminals S1 and S2. At this time, p22
At 1, the sleep timer is stopped. The p222 checks the received contents and branches the received contents to one of the following five types. The first is
In TEST (TEST unit ready) of p230, this is a path for inquiring whether or not the scanner module can scan the document, and in p231, the automatic document feeder 280 which is a selective addition device (option). , Responds to the scanner module preparation status including the film projector 290. p290 is a route when a self-diagnosis DIAG (DIAGnostic) is requested from the scanner, and is typically obtained after the failure occurrence notification functions p205 and p212 notify the failure, and p291 to p293.
Performs self-diagnosis and its answer process.

P240 is an inquiry SENS (Mode SENS) for various setting modes of the scanner module 200.
In step e), the currently set scanning mode of the scanner module 200 including the automatic document feeder 280 and the film projector 290 is answered in the processing from p241 to p245.

P250 is various setting mode setting SEL (mo
de SELECT) This is a path at the time of request and forms a pair with SENS. Various parameters are set by each routine of p251 to p256.

Reference numeral p260 is a pass for a SCAN or COPY request, which is normally once for one original in monochrome processing.
In the case of the RGB processing in the color processing, the request is made three times, and in the case of the CMYK processing, the request is made four times in succession. At the time of this request, first the motor 210 is activated in p261, and then p26
In step 2, the home sensor 211 is monitored to detect the passage of the carriage 208, and a calibration operation for resetting the position counter provided in the RAM is performed. The position counter is incremented by 1 by a sync pulse generated by the first sync signal generator SYNC once for each scanning line. In p263, the image leading edge 202S is correctly displayed after t5 hours from the time of the previously received SCAN or COPY request (FIGS. 6 and 9).
And the mode setting SEL (mode SEL
ect) The drive plan (timing in drive control) of the motor 210 for aiming for the steady state of the scanning speed Vsub set by the request is calculated. Next, in p264, the reference white board 202
SH is read, the shading correction parameter is calculated and set, and is used for the shading correction of the subsequent image reading data.

Subsequently, the bar code 202B is read at p265, the acceleration control is performed at p267, and when the desired speed is reached, the constant speed control is switched at p268. p270
Monitors whether or not the count value of the position counter has reached the document leading edge position, and when it reaches the position, the process proceeds to p267. p26
Reference numeral 7 opens the entrance gate of the FIFO, which is a buffer memory for image data, and prepares to receive the image signal from the basic image processing circuit 300 through the image signal line 300D.

Thereafter, p271 to p274 are a group of tasks for sending the original image data to the FIFO. First, in p271, the first sync signal generator SYNC detects a sync pulse generated every scanning line. In p272, the image data of 4752 pixels for one scanning line is transferred to the FIF through the image signal line 300D.
Store in O. At this time, the carriage position counter is incremented in p273. In p274, it is checked whether or not this loop is equivalent to the original image size (for one surface), for example, in the case of A3 size, 6720 scanning lines, that is, 6720 scanning lines are repeated. After scanning one surface, p275
Closes the entrance gate of the FIFO, receives the detection result from the special document detecting circuit 500 (FIG. 3) in p276, and p27
In step 7, the color detection result is received from the color original automatic detection circuit 320 (FIG. 3). The transfer of such information is performed through the bus BUS. Next, the motor is inverted and driven at p278, and p2
The home is detected at 79, and the motor 210 is stopped at p280. Further, in p223, the sleep timer is started.

[Image reader (207, 250): FIG. 3] In FIG. 3, 207 is a color image pickup device, 252 in the original image reading circuit 250 is an analog / digital converter, 253 is a shading correction circuit, 254 is a sampling position deviation compensating circuit. Original picture (original) 18
0 is placed on the platen 202 with the copy surface down and the reading start position at the left end 202S of the platen. The imaging lens 205 reduces and projects the original image onto the light receiving surface of the imaging device 207. The image pickup device 207 is a charge-coupled device (CCD) and has a color image pickup function. One-dimensionally arranged R image pickup units of 4752 pixels covered by a red filter and one-dimensional array of 4752 pixels covered by a green filter. The G image pickup section is arranged and the B image pickup section, which is one-dimensionally arranged with 4752 pixels covered with a blue filter, is arranged in parallel in three columns in the main scanning direction (direction perpendicular to the plane of FIG. 3). The three rows of image pickup units are almost adjacent to each other, specifically, at an interval of 4/16 mm in terms of the original screen 180. The scanning direction of this one-dimensional imaging device will be referred to as main scanning, and the direction orthogonal to this will be referred to as sub-scanning. The illumination lamp 203 and the first mirror-204A are mounted on the first carriage 208, and the second mirror-204B and the third mirror-204C are fixed to the second carriage 209.

When the original screen 180 is read, the first carriage is at the sub-scanning speed Vsub and the second carriage is at the speed of Vsub / 2, and the optical conjugate relationship is maintained by the original picture scanning motor 210 and the drive wire 210W. As it is, the scanning (sub-scanning) drive is performed from the left end to the right end. A stepping motor is used as the motor 210. Sub-scanning speed Vsub
Is variable in 1% increments from 1/8 to 4 times the reference speed, and an arbitrary speed is selected by a command (magnification instruction) from another module.

[Functions of Image Readers (207, 250): FIG. 9] FIG. 9 shows image reading mechanisms (203 to 206:
The velocity diagram of FIG. 6) is shown. The original image scanning will be described with reference to this. The first carriage 208 normally stands still above the carriage home sensor 211 and stands by. The sensor output at this time is ON. When the scan command SCAN or REQ is received, the lamp 203 is turned on at t1.
The motor 210 is driven to start scanning to the right. After t2, the carriage 208 goes out of the detection range of the home sensor 211, and the output is turned off. This deviated position is stored as a scanning reference position (start point) and used as a calibration reference point for the sub-scanning position. Further, the scanner controller 230 calculates an optimum acceleration plan to achieve the arrival time t5 to the image leading edge 202S and the required accuracy of the speed Vsub, and calculates the step pulse train of the motor 210. Thereafter, the carriage speed is driven by this pulse train, and the time to reach the image leading edge 202S and the desired constant speed scanning are achieved as planned. After passing the calibration reference point, the imaging device 207 reads the image of each color projected by the lens 205 in units of main scanning lines regardless of the sub-scanning speed. This is convenient for keeping the charge storage time of the imaging device 207 constant. The main scanning cycle is the pulse train cycle t generated by the first synchronization signal generator SYNC.
s1 and the pulse train is connected to the reading circuit 250 via the bus BUS. The first synchronization signal generator SYNC divides the original oscillation frequency of the crystal oscillator XTL connected here and outputs it to the bus BUS. The total number of pixels of the image pickup device 207 is 4752, and one main scanning line is decomposed into 16 pixels / mm in terms of original image, sampled and read, and an analog voltage corresponding to RGB reflected light in pixel units from the original image 180 is output. .. After that, the A / D converter 252 outputs an 8-bit digital signal (R, G, B image data).
, That is, quantized into 256 gradations, and passed to subsequent circuits.

After passing through the calibration reference point, the white reference plate 202SH is first read at t3, and the 8-bit digital conversion value is stored in the shading correction circuit 253. The image data read thereafter is effectively subjected to the shading correction. At time t4, when the carriage 208 passes under the individual identification bar code plate 202B for tracking illegal copying of securities, remote service, etc., this is read and the image data is read. It is transmitted to the system control module 600. Next, at the time t5, the original image tip 20
When 2S is reached, the image reading circuit 250 causes the original image 18
0 is read in scanning line units, and as the color separation digital data 250D for each pixel, the basic image processing circuit 30 of the next stage is sequentially arranged.
Output to 0. All of the A3 size original images 180 and 6720 scanning line segments are read, and the carriage 208 reaches the right end, and t6
When the time comes, turn the motor 210 in the opposite direction to
It returns to the scanning position 211 and is stopped to prepare for the next scanning.

[Basic Image Processing Circuit 300: FIG. 3] In FIG. 3, 301 is a spatial filter circuit, 302 is a variable magnification circuit, 303 is a color processing circuit, 304 is a gradation processing circuit, 31
Reference numeral 0 is an image area automatic separation circuit, 320 is a color document automatic detection circuit, and 500 is a specific original image detection circuit.

[Function of Basic Image Processing Circuit 300: FIG. 3]
The spatial filter circuit 301 shown in FIG. 3 performs smoothing processing or sharpening processing. Generally, when the original image (original) 180 is a halftone dot printed matter, the former process is performed, and when the original is only a character, the latter process is performed. The selection is input on the original designation screen of the console 800, or depends on the separation result from the image area automatic separation circuit 310 described later. Magnification circuit 3
02 scales the image in the main scanning direction by 25% to 400%. The copy scaling in the sub-scanning direction is achieved by changing the image reading speed (sub-scanning speed: speed of the motor 210).

The color processing circuit 303 masks the RGB signals (R, G, B image data) of the original image to record the color signals C (cyan), M (magenta), Y.
(Yellow), K (black) image forming signals (image data of each recording color
Data). Further, so-called adaptive color processing such as color processing suitable for the character image and the grayscale image, for example, pure blackening processing of the black character portion is performed. If necessary, R
As the GB signal is passed through the scanner controller 230, as shown in FIG.
To the system control module 600. The gradation processing circuit 304 performs dither processing from any of the 8-bit CMYK image signals to create a 4-bit recorded image signal.
Further, so-called adaptive gradation processing, which is gradation conversion suitable for each of the character image and the grayscale image, is performed. The image area automatic separation circuit 310 discriminates a character image portion and a grayscale image portion on one original image on a pixel-by-pixel basis, and the result is determined by the spatial filter circuit 3.
01, the color processing circuit 303, and the gradation processing circuit 304. The color document automatic detection circuit 320 performs color document / black and white document identification processing. The specific original image detection circuit 500 determines whether the original 180 is a specific original image such as securities whose copying is prohibited. When a specific original image is detected, the image signal is altered, for example, by blackening the entire surface. The specific original image detection circuit 500 includes n pieces of background characteristic matching circuits, a color characteristic detection circuit, a specific mark detection circuit, a specific character string detection circuit, and a logical circuit that takes a logical sum of these detection results. An original image which is configured to be copy-unusable or copy-prohibited is detected and notified to the gradation processing circuit 304. The gradation processing circuit 304 performs image conversion of black on the entire surface. The feature of the circuit 500 is that the background characteristic matching circuit, the color characteristic detecting circuit, and the specific mark detecting circuit can be selected according to the national situation and used in an arbitrary number of combinations.

[Operation of Basic Image Processing Circuit 300: FIG. 3]
Please refer to FIG. Original image read RGB image data 2
51D is input in parallel to the spatial filter circuit 301, the image area automatic separation circuit 310, the color document automatic detection circuit 320, and the specific original image detection circuit 500, and processed in parallel. The functions of the basic image processing circuit 300 are divided into two categories.

The first category is a function for supporting an image operation instead of directly operating an image signal. For example, there are an image area separation process for discriminating and separating a character region and a gradation image region, a document size detection process, and a color document / monochrome document discrimination process. In this category of processing, for example, color document / black and white document identification processing, all document information on the platen 202 must be checked.

The second category is processing for manipulating image signals, such as spatial filtering, scaling, image trimming, image movement, color correction, and gradation conversion. These processes are further classified into those having common processing contents depending on the image area, such as scaling, and those having different two image areas of the character image and the grayscale image portion, such as gradation processing.

Most of the processing results of the first category are transmitted to the system control module 600 of FIG. Upon receiving this, the system control module 600 issues a command to the other modules based on this to proceed with the image forming process.

For example, when the basic image processing circuit 300 detects that it is a black and white original, the circuit 300 informs the scanner controller 230, the first communication unit SCSI informs the system control module 600, and the module. 600 is a printer module 400 shown in FIG.
Send a command to stop Y development. Then, the printer controller 430 in the printer module 400 energizes only the K developing device 420K to stop the development of other colors and efficiently form an image.

The image processing contents of the second category are automatically activated (selected) according to the processing result of the first category and the case where the operator operates the console 800 (FIG. 7).
Some are specified and input from the above, and some are obtained by combining these. A specific color image erasing process will be described as an example of these processes. In this process, a specific color included in the original image is erased, other colors are saved, and the transfer paper 190 is stored.
A basic image processing circuit 3 for forming an image on A
This is achieved by the “color conversion” process by the color processing circuit included in 00. Note that the specific color can be adjusted by the operator to the console 80
Input from 0. In either case, in the copy mode, the RGB image signals input to the basic image processing circuit 300 are finally converted into recording signals C (cyan), M (magenta), Y (yellow), K ( It is converted to black) and this data is passed to the printer module 400. When the original is identified as a black-and-white original or when a black monochromatic processing command is received, monochrome processing is performed and only the K signal is output.

[Extended Image Processing Circuit 350: FIG. 3] The extended image processing circuit 350 includes the two circuits shown in FIG. 3, an image area designation image processing circuit 351 and an image editing circuit 352.
The extended image processing circuit 350 (electrical circuit board) is arranged near the outer periphery of the scanner module 200 so that it can be selectively incorporated according to the user's request.

The image area designation image processing circuit 351 has a function of subjecting the original image identification area designated by the operator to image processing different from that of other general areas. Further, the image editing circuit 352 is provided with various image processing functions, for example, image left-right reversal, mosaicization,
It has the role of forming special effect images such as solarization, posterization, high contrast, and line image. The image trimming process, which is one of the region designation image processes, will be described as an example of the process included here. In the image trimming, a specific region of the original image is copied,
This is the process of blanking the others. The processing method is JP-A-62-1.
A well-known technique as disclosed in Japanese Patent Publication No. 59570 is used. However, according to this technique, since the felt pen mark attached to the original image is attached to the original, there is a problem that the original is damaged. In view of this drawback, in the present embodiment, the original image is read by pre-scanning, and this is displayed on the two-dimensional display 820 of the console 800 (FIG. 7), and the operator can move the cursor while viewing the image. 813 and a confirmation key 814 are used to input and specify a trimming range, and the area specifying image processing circuit 351 blanks the input area.

[Printer Module 400: FIGS. 5 and 7] The printer module 400 includes an image forming mechanism 400.
img, a printer controller 430 including a second communication unit SCSI, a power supply circuit 401, and a selective accessory device (multistage sheet feeding device 480, sorter 490). The image forming section 400 img includes various image forming elements such as a photoconductor 414, a charger 419, a laser exposure device 441, a developing device 420, a first transfer device 414, an intermediate transfer member 415, and a second transfer device 427.

The printer controller 430 is mounted on an electric circuit board, and a required voltage is applied from the power supply circuit 401. A commercial voltage is applied to the power supply circuit 401 via a commercial power plug 401P and a power switch 401SW (FIG. 7). S1 and S2 (FIG. 5) are SCSI connectors having the same shape and the same interface on the printer controller 430, and F1 and F2 are selective addition devices (multistage sheet feeding device 480, sorter 490; This is an optical fiber connector for optical communication with (optional). 441 is a ray
The diode, 442 is an fθ lens, 443 is a rotary polygon mirror, 444 is a mirror, 412A is an automatic paper feed cassette for double-sided copying, 412B is a manual paper feed tray, 413A, B
Is a paper feed roll, 418R is a registration roll pair, 413
F, G, H, and J are conveying roll pairs, 414 is a photoconductor drum, 415 is an intermediate transfer belt, 416 is a primary transfer corotron, 417 is a transfer corotron, 419 is a charging scorotron, and 420C, M, Y, and K. Are cyan, magenta, yellow, and black developing devices, 420 is a developing device assembly, 421 is a cleaner, 422 is a conveyor belt, and 423A.
Is a fixing roll, 423B is a fixing backup roll, 4
24 is a discharge roll, 425 is a discharge switching roll, 42
Reference numeral 6 is an image leading edge position sensor.

[Printer Controller 430: FIG. 5] The CPU in the printer controller 430 is a microprocessor, RAM is a read / write memory, ROM is a read-only memory,
INT is an interrupt controller, PE is a serial communication unit, SYNC is a second synchronization signal generator, and XTL is a second.
Crystal oscillator, DMA for DMA controller, FIFO for first-in first-out memory, SCSI for S
Second communication unit including CSI controller, S1, S
Reference numeral 2 is the same connector, DV is an input / output circuit for various actuators such as sensors and motors, BUS is a bus, and DC is a data channel.

[Timing Control and Synchronous Control of Printer Controller 430: FIG. 12] The printer controller 430 communicates with the system control module 600 or the scanner module 200 by a predetermined protocol, and is basically the main component. Image data is acquired for each scanning line, and the image forming mechanism elements in the printer module 400 are energized and controlled to form an image based on the image forming mode of the command, and the final image (copy ) Output 190B. In addition, the printer module
The multi-stage sheet feeding device 480, the sorter 490 (option), etc., which are selectively added to the tool 400, are integrally controlled. When the image forming mode is "full color mode", CM
The YK color is formed for each surface, and the intermediate transfer belt 41 is formed.
5 is overlaid and transferred to the recording paper 190A to execute the frame sequential image forming method for forming the final image (190B). Therefore, in the full-color mode, the scanning request (color plate image data request) is output to the system control module 600 or the scanner module 200 four times for each print. Further, in each single color copy mode of RGB, each scanning request of MY, YC and CM is output twice. In color image formation, the intermediate transfer belt 415
It is important to ensure the accuracy of registration (registration) for each color plate.

This alignment (registration) will be described with reference to FIG. FIG. 12 shows the synchronization of image signals for one color. First, a data request command REQ is sent to the system control module 600 or the scanner module 200 to receive the image data. This indicates that the method of sending before a fixed time t5 is adopted. In color image formation, in the second and subsequent color plate formations, the data request signal REQ may be issued before t5 time when the leading edge of the previous color plate image will reach the exposure point 441X (FIG. 12). become. In order to accurately measure the time at which the leading edge of the previous color plate will reach 441X, the image leading edge sensor 426
Are provided so as to face the intermediate transfer belt 415. Basically, the distance L1 from the exposure point 441X to the primary transfer point 414T added to the product of the peripheral velocity Vpc of the photoconductor and t5;
When the distance L2 from the primary transfer point 414T to the detection position of the image leading edge sensor 426 is made equal, and in the second and subsequent color plate formation, when the sensor 426 detects the leading edge of the image of the color formed before, data request is made. Issue signal REQ.

This so-called constant time advance data request method is as follows:
This is particularly effective for a data transmission source such as a scanner module 200 whose scanning means (carriage) has a certain mass and requires a certain amount of preparation time before outputting image data. is there. When the data request command REQ is transmitted in this manner, the scanner module 20
According to the module-to-module protocol, as described in section 0, the data source (scanner) is the first one after t5 hours.
Scan line data is available. This ensures synchronism with respect to the phase (front end alignment of each color image).

Next, in order to achieve "synchronization" so that each color component at the same point on the original document becomes the same point on the recording paper, first, in synchronization with the pulse train period ts2 generated by the second synchronization signal generator SYNC, 1 The recording data of the scanning line segment is received from the other party (scanner / host) and put in the reception buffer FIFO. Further, the rotary polygon mirror 442 is driven in synchronization with the pulse train period ts2, specifically, the phase lock servo drive is performed, and the mirror surfaces are switched at the period ts2 (line switching). As a result, the bright spot 441X of the laser 441 exposes and scans on the photoconductor 414 at a cycle of ts2. Further, as a matter of course, during the bright spot scanning, the laser drive circuit 441DV drives the image data D1 for one line.
To D4752, the laser 441 is controlled to be lit 4752 times in pixel units. In the copy mode, the data
The data transmission side is the scanner module 200, and in the printing mode, the data transmission side is the system control module 600 to maintain the above synchronization mechanism.

Therefore, no matter how many times the original image is scanned, the recorded image data is always obtained after a fixed time from the reception of the command, and the positional relationship (registration) between the paper and the image recorded on it is correctly maintained. The registration of the different color images (color plate registration) is maintained.

The present color plate registration system is also characterized in that the image forming interval for each color plate can be arbitrarily set. In the image formation of the A4 size color copying mode of the present embodiment, one color is formed for each cycle (one turn) of the transfer belt 415, and in the image formation of the A3 size color copying mode, the transfer is performed. By forming one color every two cycles of the belt 415, a sufficient time for color plate exchange such as rotation of the developing device assembly 420 is ensured.

Further, in the image formation of the color print mode in which the recorded image data is received from the module different from the scanner module 200 to form the image, one color is formed regardless of the image size. It became possible to insert an optional pause time each time. Accordingly, R included in the system controller 630
Even if the image data memory such as AM has a relatively small amount of hardware and the CPU has a normal capacity,
The print processing PR of the application processor 650 develops an output image into bitmap data without being restricted by time for each color, and when the one-color data is completed, the system control module
Data is transferred from the printer 600 to the printer module 400, and the printer module 400 forms one color.

[Function of Printer Controller 430: FIG. 13,
14] FIGS. 13 and 14 show the control operation of the printer controller 430. The functions shown in these drawings are executed by the program execution of the CPU of the printer controller 430. The execution program is stored in the read-only memory ROM.

Reference numeral p401 in FIG. 13 indicates the operation of turning on the power supply 401, and p402 indicates initialization processing, for example, initial parameter setting of various circuit elements, watchdog timer start, 4
It is a function such as initial alignment of the color developing device aggregate 420. In p403, it is determined whether or not the command input from the terminals S1 and S2 has not come within a predetermined time. p40
Reference numeral 4 denotes a function of turning off the heater power supply of the fixing device 423, which contributes to reduction of power consumption during standby. p405 is generated when the watchdog timer leaves normal execution of the program, and at this time, the failure occurrence notification function p405 notifies the system control module 600 of this. p201 is an interrupt vector when a failure occurs in the image forming mechanism 400img or other modules 400, p411 identifies the failure part and analyzes the cause, and p412 notifies the system control module 600 of this. To do. p413 is, for example,
If the 414M is overheated, a fail-safe process is performed to avoid the risk of fire.

Referring to FIG. 14, p420 indicates a terminal S
The interrupt vector when there is information input to S1 and S2,
At this time, the sleep timer is stopped at p421. p42
2 checks the received content and branches it to one of the following 5 types. First, p430 TEST (TEST unit re
ady) is a route for inquiring whether or not the printer module 400 can form an image. In p431, the printer module state including the selective addition devices 480 and 490 is answered. p490 is a route for requesting a self-diagnosis DIAG (DIAGnostic) from the printer, and is typically obtained after the failure occurrence notification functions p405 and p412 notify the failure, and p491 to p493.
Performs self-diagnosis and its response process.

P440 is an inquiry SENS (Mode SEN) for various setting modes of the printer module 400.
In Se), the printer module model including the selective addition devices 480 and 490 is processed in the processes of p441 to p445.
Answer the setting status. A p450 is a path at the time of requesting various setting mode setting SEL (mode SELECT), and forms a pair with the above SENS. Various parameters are set by each routine of p451 to p456. In p456,
It is registered in advance that the destination of the recorded image data request is the scanner module 200 in the case of the copy mode and the system control module 600 in the case of the print mode.

P460 is the path for PRINT request,
In the normal monochrome image forming process, 1 is applied to one print.
4 times for the full color processing and 2 times continuously for the secondary color monocolor processing. As described above, even if a plurality of PRINT requests for one print arrive at irregular intervals, it is possible to perform control so that each color plate is correctly overlaid. At the time of this request, first, the motor 414M is activated in p461, then the image formation sequence control is started in p462, and p463
The monitoring operation of the tip sensor 426 is monitored by. When the sensor detects the leading edge of the image, p467 is immediately activated,
The data transfer request signal REQ is sent to the scanner module 200.
Alternatively, it is output to the system control module 600. p
At 465, the line counter (scan line counter) provided in the memory RAM is reset. This counter is incremented by 1 by a synchronization pulse generated by the second synchronization signal generator SYNC once for each scanning line. p466 is the time from the generation of the data transfer request signal REQ until the data transfer destination prepares the data of the first line,
In other words, when an image of another color already exists, it is a task of monitoring the time corresponding to the cyclic return of the image to the exposure position 441X. When this time elapses, p467 resets the line counter for the second time, and FI which is a buffer memory for image data is further reset.
Open the exit gate of the FO, and lay out via the image signal line DC.
The driver 441D prepares to deliver a recorded image signal. Thereafter, p468 to p472 are a task group for storing the recorded image data, which is taken from the terminals S1 and S2, in the FIFO for each scanning line. First, in p468, the second synchronizing signal generator S
The YNC detects a sync pulse generated every scanning line. p469 is one scan line 4 acquired from terminals S1 and S2
The recorded image data for 752 pixels is stored in the FIFO. At this time, the line counter is incremented in p470. In p472, this loop is equivalent to the recording size, for example, in A3 size paper, 6720 scanning lines, that is, 6720 times are repeated. When laser scanning for one surface (A3 size, 6720 times) is completed, p473 becomes 43.
0FIFO exit gate is closed, laser driver 441
The drive signal of D is cut off. At this time, of course, the terminals S1 and S
The acquisition of recorded image data from 2 is also completed.

In p474, it is checked whether or not the image formation this time is the last color image formation of the last recorded color image. If the color is not the final color, the remaining image forming sequence control is completed, and the motor is stopped at p480. If the final color image formation has been completed, p474 to p4
The paper feed, secondary transfer, fixing, and paper discharge processes described in 78 are executed, and the recorded image 190B is printed on the printer module 400.
Discharge to the outside.

[Operation of Image Forming Mechanism 400 img: FIG. 7] The printer module 400 includes the printer controller 43.
Based on 2-bit recording data of pixel density 1/16 mm or 1/24 mm for main scanning and sub scanning for each CMYK color input to 0, recording dot density for each CMYK color for both main scanning and sub scanning on transfer paper 1/16 mm or 1
A full color visible image consisting of a / 24 mm dot pattern is formed and output. The selection of dots having a recording dot density of 1/16 mm or 1/24 mm is designated in advance by a mode selection command. The default is a dot density of 1/16 mm. When the image forming cycle is started, first, the photosensitive drum 414 is rotated counterclockwise and the intermediate transfer belt 415 is rotated clockwise by the drive motor 414M. With the rotation of the intermediate transfer belt 415, C toner image formation, M image formation, Y image formation, and K image formation are performed, and finally CMYK.
A toner image is formed on the intermediate transfer belt 415 in this order.

First, C image formation is performed as follows. The charging scorotron 419 uniformly charges the photosensitive drum 414 with negative charges to −700 V by corona discharge. Then, the laser diode 441 performs raster exposure based on the C signal. A recording signal (recording image data) for image formation is sent from the scanner module 200 in a general copy mode, and a special copy mode including an intelligent image processing or a facsimile mode. It is supplied from the system control module 600 in the print mode or the print mode.
In the copy mode, to the scanner module 200, and in the print mode and the facsimile mode to the system control module 600, "recorded image data can be sent after a predetermined time. The data request signal REQ "" is issued.

The recording signal is the SCS of the printer controller 430.
The laser drive circuit 441DV which is input from the I terminal S1 or S2 and is a recording control circuit controls the light emission of the laser diode 441 in input pixel units based on the recording signal.
The recording signal is 4 bits per pixel. More specifically, when the pixel has the highest C density, only the entire main scanning width is read.
In the case of an intermediate density signal, it emits light for a time proportional to the density data.

When the raster image is exposed in this way, in the exposed portion of the photosensitive drum 414 that is initially uniformly charged, the charge proportional to the amount of exposure light disappears and an electrostatic latent image is formed. . The toner in the developing device 420C is negatively charged by stirring with the ferrite carrier, and the cyan developing roll 420C of the developing device 420C is negatively charged with respect to the metal base layer of the photosensitive drum 414 by a power supply circuit (not shown). Is biased to a potential in which the direct current potential and the alternating current are superimposed. As a result, the toner does not adhere to the portion of the photoconductor 414 where the electric charge remains, and the C toner is adsorbed to the non-charged portion, that is, the exposed portion, and the C visible image (C A toner image) will be formed.

Further, in the laser drive circuit 441DV, in addition to the light emission control based on the recording signal of the laser diode 441, special image pattern data is generated at the time of Y image formation,
This is unconditionally added to the input image data. That is, it has a function of driving the laser diode 441 by the logical sum of the input image data and the special image pattern data. This pattern is a fine image in which the system identification number is patterned, and is attached to assist in tracking this when an illegal image such as securities is formed by some method.

In this way, when the toner image on the photoconductor rotates counterclockwise and reaches the position opposite to the primary transfer corotron 416, the toner image comes into contact with the photoconductor and the intermediate transfer belt 415 driven at the synchronous speed. Corona transcribed. Photoconductor 414
Some of the above untransferred residual toner is cleaned by the cleaning device 421 in preparation for reuse of the photoconductor 414. The toner recovered here is stored in a waste toner tank (not shown) via a recovery pipe. The intermediate transfer belt 415 is
In particular, in order to maintain good image carrying characteristics for a long time, which is often required in a printing mode, a material having a relatively large specific resistance value is used. As a result, even if it takes a long time, for example, 20 minutes, until the next M toner image is formed,
It became possible to carry without disturbing the image.

Next, prior to performing the M image forming raster exposure based on the M signal, the developing device assembly 420 is rotated counterclockwise so that the M developing roll 420M faces the photoconductor 414. Next, the leading end position of the C visible image previously formed is detected by the leading end detection means 426, and the scanner module 20 is detected.
0 or request signal REQ for system control module 600 to "send recording M data after a predetermined time"
Emit again. This request signal is sent to the image position detecting means 42.
6 is issued when the registration (toner registration) C toner mark image, which has been added slightly ahead of the effective C image in the previous step, is detected. Further, instead of the C toner mark, a system in which a permanent mark is previously attached to the intermediate transfer belt may be used. This request signal RE
If the M signal is sent in synchronism with Q, M image exposure, development, and primary transfer are performed, and accurate color plate alignment is performed on the original existing C image, that is, on the intermediate transfer belt 415. C
The M image will be correctly superimposed on the image. When the M raster image is exposed in this manner, in the exposed portion of the photosensitive drum 414 that is initially uniformly charged, the charge proportional to the amount of exposure light disappears and an electrostatic latent image is formed. The M toner in the developing device 420M is negatively charged, and the developer of the developing roll 420M of the present developing device is the photosensitive drum 41.
4 and is biased to the same potential as in C development. Therefore, the toner does not adhere to the portion of the photoconductor 414 where the electric charge remains, and the M toner is applied to the portion exposed by the M signal.
Will be adsorbed, and an M visible image similar to the electrostatic latent image will be formed. Similarly, the Y image is displayed on the CM toner image as K
The images are formed on the CMY images in an overlapping manner.
The intermediate transfer belt 4 thus rotated at least four times
The full-color image formed on 15 is secondarily transferred 4
It is transferred to 17 parts. On the other hand, at the time when the image formation is started, the transfer paper 190A is fed from the three feeding units, that is, the cassette 412A, the manually inserted paper feeding tray 412B or the external feeding port 412C.
3B or the feeding roll pair 413F is fed by the feeding or feeding action, and stands by at the nip of the registration roll pair 418R.

When the tip of the toner image on the intermediate transfer belt 421 reaches the secondary transfer corotron 427,
Just as the front end of the transfer paper 190A coincides with the front end of the image, the registration roll pair 418R is driven to register the paper and the image. In this way, the transfer paper is superposed on the intermediate transfer belt image and passes under the secondary transfer corotron 417 connected to the positive potential power source. At this time, the transfer paper is positively charged by the corona discharge current, and most of the toner image is transferred onto the transfer paper. Then, when passing through a neutralization core (not shown) connected to a grounding source arranged on the slightly left side of the secondary transfer corotron 417, the transfer paper discharges electric charge, and the attraction force between the intermediate transfer belt and the transfer paper almost disappears. . Eventually, the weight of the transfer paper exceeds the suction force, and the transfer paper 190 is separated from the intermediate transfer belt 421 and transferred to the transport belt 422. The transfer paper on which the toner image is placed is sent to the fixing device 423 by the carrying belt 422. At this time, the fixing roll 423A and the backup roll 423 heated.
Heat and pressure are applied in the nip portion of B, the toner is melted, and the fibers of the transfer paper 190A are embedded in the toner and fixed. That is, Copy-190B is completed. Completed copy 190
After that, B is sent out of the main body by a pair of discharge rolls 424. The discharged copy paper 190B is stacked face up on a tray (not shown).

When copying on both sides, the switching
Move the rule 425 to the right along with the paper deflection, and
Then, the transfer sheet is once inverted to be reversed, and then guided by a conveying roll pair 412H to a double-sided copying / automatic sheet feeding cassette 412A. At this time, the copied transfer sheets 190C are stacked with the copy side facing up.

[System control module 600: FIG.
FIG. 7] The system control module 600 is an outline, and includes a system controller 630, a console 800 including a key input board 810 and a bit map display 820, a floppy disk device 740, a magneto-optical storage device or a CD.
-ROM drive device 730, IC card drive device 74
5, third communication unit SCSI and acceleration processor 750
Composed of. These are all housed in the housing of the module 600. The module 600 can be fitted and fastened to the connector 400AL2 on the upper portion of the printer module 400 by the connector 600AL1.

Referring to FIG. 7, the console 800 is
The operation surface is exposed on the upper side, and it is arranged on the front side so that the scanner module 200 can be operated even when it is stacked. Further, the floppy disk device 740, the magneto-optical storage device or the CD-ROM drive device 730 and the IC card drive device 745 are provided with the recording medium insertion surface at the front side in consideration of usability, and the connector S of the third communication unit SCSI is used.
1, S2 is a back surface.

[System Controller 630: FIG. 4] The CPU of the system controller 630 is a microprocessor, RAM is a read / write memory, ROM is a read-only memory, and I
NT is an interrupt controller, SYNC is a synchronization signal generator, XTL is a crystal oscillator, and DMA is a DMA controller.
La, FIFO is a first-in first-out memory, SCSI is the SC of the third communication unit.
SI controller, S1 and S2 are SCSI terminals, BUS
Is a bus, DC is a data channel, and 650 is physically a magnetic disk drive, but it is also called an application processor because it functionally stores a system control program. A magnetic disk is used as a storage medium, for example, a ROM.
There is no problem in substituting for.

The first function of the system controller 630 is to enable various module configurations as shown in FIGS. 1 and 2, specifically, system control in each of the various module configurations. Is. The second function is control of the console 800 such as screen display and key input, and the third function is a communication control function with a facsimile or an external host computer and a recorded image data expansion function. is there.

[Application Processor 650: FIG. 4] Application Processor 6
Reference numeral 50 denotes various processing functions (programs), copy processing CP,
It is composed of various processing functions (program on the magnetic disk HDD) of the facsimile processing FX, the printing processing PR and the intelligent image processing AI. All of these processes share the hardware resources of the system controller 630 and are implemented in the form of executing a program stored in the magnetic disk HDD. The copy process CP is a scanner module 2
00, a printer module 400, and a system control module 600 are connected to each other to integrally control the entire system to realize an image copying function. The facsimile processing FX is processing for realizing a facsimile function in a system in which the scanner module 200, the printer module 400, the system control module 600, and the public line 650FC are connected. The print processing PR is a system in which the printer module 400 and the system control module 600 are connected to each other and the print data is received from an external computer. This is a process for realizing the print function to be performed. The intelligent image processing AI is processing for realizing intelligent image processing in a system in which the scanner module 200 or the printer module 400 and the system control module 600 are connected.

Here, the intelligent image processing means, for example, recognizing a character from an image read by the scanner module 200 and creating a graph based on the character.
And the output image 190B are subjected to significantly different image processing. The intelligent image processing differs from the general copying mode in that the image data is temporarily transferred to the system control module 6
Image data is processed by the intelligent image processing CP, and the processed image data is transferred to the printer module 400 to form an image.

[Function of the application processor 650: FIGS.
8] FIG. 15 is a flow chart showing the processing contents of the copying process CP and the printing process PR, FIG. 16 is a time chart showing the operation of the modules 200, 400 and 600 appearing by the copying process CP, and FIG. 17 is a printing process. FIG. 18 is a time chart showing the operation of the modules 200, 400 and 600 which is displayed by the processing PR. FIG. 18 shows the modules 200, 400 when a failure occurs during execution of the copy processing CP.
6 is a time chart showing the operations of the above-mentioned and 600.

In FIG. 15, a thin line frame indicates a process common to the copy process CP and the print process PR, a thin broken line frame indicates a process peculiar to the copy process CP, and a thick line frame indicates a process peculiar to the print process PR. p601 is a start address when the printer module 400 is powered on. Printer module 4
00 is turned on because the system control module 600 is assembled together with the printer module 400 so as to receive power supply from the printer module 400. In p604, parameters on various software, for example, interrupt controller IN
Initialize the internal register of T. The step p602 indicates that the watchdog timer has timed out, the data to be backed up is protected, the data is saved, and the process branches to the initialization process. p605 monitors the presence or absence of various events, and p606 examines the contents and jumps to four types of paths.

The step p610 branches when the notification of the failure occurrence is received from the scanner module 200 or the printer module 600, and the contents are confirmed from p611 to p614. p615 displays on the display 820 so that the operator can understand the details of the failure.
In step 2, the service center connected by the public line is notified of the information. p617 receives an instruction such as a failure recovery procedure from the service center, and this is displayed on p618. The step p620 branches when a notice of an abnormality occurrence is received from the scanner module 200 or the printer module 600. Abnormality here means a state such as supply shortage of a toner or recording paper or opening of a housing door, supply of a supply or closing of a door, which can easily be brought to a normal state. The contents are confirmed from p621 to p624. The display on p615 shows the details of the abnormality.
0 is displayed, and p625 displays a message regarding the procedure for returning to the normal state, such as urging the supply of supplies.
00 on the display 820.

In p660, the operator is console 80.
Various copy modes input from 0, for example, when the mode is set such as the designation of the image processing mode or the sort mode, or when the setting command is received from the host computer in the printing mode. , Display 820 on p661
A response screen is displayed and a mode setting command is sent to the scanner and printer modules 200 and 400.

P630 branches when the start button 811 is pressed or when a start command is received from the host computer in the print mode, and the printer module 400 is inquired about the preparation status from p631 to p632. . In the copy mode, p633 to p63
In step 4, the scanner module 200 is inquired about the preparation status. If these are ready, a COPY command is sent to the scanner module 200 at p635 only in the copy mode. In p636, a PRINT command is sent to the printer module 400. In the case of the copy mode, this is the scanner module 200 and the printer module 400.
Commands are exchanged between them, image data is transmitted and received according to the procedure described in the section of the module, and a copy is generated. In the printing mode only, in p636, the image data for one page of one color is transferred from the system control module 600 to the printer module 400 according to the procedure described in the section of the printer module. p637 to p640
Inquires whether the series of image reading process and image forming process has been completed. If it has returned to the initial state, this is displayed on the display 820. p64
In step 2, it is checked whether or not a predetermined color plate and a predetermined number of copies have been completed, and if the remaining image formation is still required, the process returns to the beginning. At the time of color copy, this loop is repeated four times.

[System Operation Timing: FIGS.
8] FIGS. 16, 17 and 18 show the signal flow and timing of the three modules 200, 400 and 600, and FIG. 16 shows the operation timing of the copy mode (CP). FIG. 17 shows the operation timing of the print mode (PR), and FIG. 18 shows the operation timing when a failure such as a transfer paper jam occurs during execution of the copy mode (CP).

[Operation Timing of Copy Mode: FIG. 16]
Reference is made to FIG. The system control module 600 is
By the action of the copying process CP, the PRINT command is issued four times for four colors at equal intervals.

[Operation timing of print mode: FIG. 17]
Reference is made to FIG. The system control module 600 is
By the action of the printing process PR, the PRINT command is issued four times for four colors at regular intervals instead of at regular intervals. When there is a lot of print data, the PRINT command issuance interval is generally much longer than the copy mode interval. Also, as a result of the unevenness of the color data size handled by the print processing PR and the non-uniformity of the software development work of the bitmap data, it appears as a variation in the image data processing completion time, and the PRINT command is adjusted to this variation. Are issued at unequal intervals.
In the print mode (PR), the scanner module 20
0 does not participate at all, and it works without any problem even if it is physically cut off.

[Operation Timing at Failure: FIG. 18] FIG. 1
FIG. 8 shows an example of processing timing when a transfer paper jam occurs in the printer module 400 in the copy mode (CP).

As described above, the printer control means
(430) irregularly receives image data for each color plate, and when the specific color plate data is received, the image forming means (400 img) is urged to form an image of the specific color, and After the plate image is formed, it is output as a visible image on the recording medium (190A). Therefore, when viewed from the external computer, the degree of freedom in timing of data transfer for each color plate is high, and the versatility of the color image forming apparatus is high. A memory for accumulating a huge amount of print data for each color is substantially unnecessary.

The image leading edge position detecting means (426) detects the leading edge of the color plate image already formed, and the printer controlling means (430)
Executes a series of color plate registration control. Therefore, even if the image forming intervals between the color plates are random, the registration between the different color plates is always performed accurately,
No color shift occurs.

A multicolor image is temporarily formed on the intermediate transfer belt (415) so as to be superposed thereon, and then transferred to the final recording medium (190A) and outputted. Therefore, even if the image forming interval between the color plates is random and there is an environmental change such as a temperature change, the color plate registration is always performed accurately and no color shift occurs.

The printer control means (630) irregularly receives the image data for each color plate, and when the specific color plate data is received, the image forming means (400img) forms an image of the specific color. The image forming means (400 img) converts the image data for each color plate into a visible image, forms the visible image, and outputs it as a visible image on the recording medium (190A). Further, the scanner module (200) converts the original image into recorded image data and outputs it, and the system control means (6
00) issues color plate image forming commands at equal intervals in the copy mode, and issues color plate image forming commands at non-equidistant intervals in the print mode. Therefore, in the color image copying mode,
A color image is formed in the shortest time, and in color printing mode, when viewed from an external computer, the degree of freedom in timing of data transfer for each color plate is high, and the versatility of the color image forming apparatus is high. Is high. A memory for accumulating a huge amount of print data for each color is substantially unnecessary.

The basic configuration and operation of the color image forming apparatus according to the embodiment of the present invention have been described above. Next, the basic image processing circuit 30 of the scanner module 200
0 configuration and operation of the system control module 600
It will be described in detail together with the processing of.

-Details of partial functions of the basic image processing circuit 300: FIGS. 19 to 26- [ACS ON mode] FIG. 19 shows a scanner module.
The configuration of the basic image processing circuit 300 of the module 200 is shown in some detail. First, in the copy mode, a color document / black and white document identification mode (ACS: Auto Color Selection) is performed by the operation unit connected to the system control module 600.
When is selected (ON), the scanner module
RGB input to the basic image processing circuit 300 of the module 200
In the color original automatic detection circuit 320, the data is discriminated between a color original and a monochrome original.

In parallel with this, in the color processing circuit 303, K
An image forming signal for color is calculated, subjected to γ correction and dither processing in the gradation processing circuit 304, converted into a 4-bit recording signal, and sent to the printer module 400. In this ACS ON mode, the color processing circuit 303
The color processing parameter is set so as to calculate the K amount corresponding to CR100%.

The printer module 400 energizes the K developing device to form a K color toner image on the photoconductor on the basis of the transferred image recording signal and further forms the intermediate transfer belt 415.
The toner image is transferred onto and held. When the first scanning of the original is completed, the color original automatic detection circuit 320 outputs a discrimination signal of a color original or a monochrome original. At this time, if the original is identified as a black-and-white original, the image formation is ended and the step of transferring to recording paper is started. If it is identified as a color original,
The color processing circuit 303 of the basic image processing circuit 300 is changed to the color processing parameter for calculating the image forming signal for cyan, and the printer module 400 activates the C developing device to continue the image formation. Thereafter, when a full-color toner image is formed on the intermediate transfer belt by forming magenta and yellow images, the toner image is transferred to the recording paper and is conveyed to the fixing device 426 by the conveyance belt 422, and the toner image is formed on the recording paper. A fixed copy image is obtained.

In this ACS ON mode, 1
The original color cannot be identified until the scanning of the original is completed, but since the color processing circuit 303 sets a parameter corresponding to UCR 100%, in the case of a monochrome original, the recording signal is originally formed only by K, and CMY is used. Since the color component of is almost 0, a black-and-white image with no information loss can be obtained even if the image formation is stopped by K alone. In the case of a color original, a natural full-color image can be obtained by subsequently forming a CMY color component image and superposing it on the K image.

With this method, since there is no unnecessary document scanning,
This is advantageous in terms of copy speed, and is particularly useful when a black-and-white original and a color original are mixed and continuously copied using an automatic original feeder (ADF: Auto Document Feeder).

However, from the viewpoint of image quality, there are the following problems. That is, in the method in which the toner images formed on the photosensitive member are transferred onto the transfer medium a plurality of times to superpose the toner images of a plurality of colors, the toner image transferred onto the transfer medium at the first time is the second color. During the subsequent transfer to the transfer medium, it comes into contact with the photoconductor again. At this time, due to the adhesive force acting between the toner and the photoconductor, the toner transferred to the transfer medium is reversely transferred to the photoconductor, or the electric field generated by the influence of the charged photoconductor causes the toner on the transfer medium. Of the toner is scattered, and the image quality is deteriorated such that the lines are blurred or blurred particularly in the character and line drawing image portions. This deterioration occurs as the number of re-contact with the photoconductor increases.
In other words, the faster the image forming order is, the larger the color is, and when K is imaged first, the quality of black characters, which requires particularly high resolution, is inferior in a document in which a black character image and a color image are mixed in one document. There is a defect.

As described in the above examples, when the intermediate transfer member is used as the transfer medium, this deterioration is more remarkable. Compared to the method of directly transferring and superimposing the toner image on the recording paper, the method of using the intermediate transfer member does not require the recording paper to be wound around the transfer drum. Therefore, it is possible to wind the recording paper around the drum such as thick paper, OHP sheet, and small size paper. Although it has the great advantage of being able to form an image on recording paper that is difficult to transfer, the toner that remains as a transfer residue on the transfer body in this transfer step increases because the number of steps for transferring the toner image from the intermediate transfer body to the recording paper increases. In consideration of the above, the influence of the decrease in the toner adhesion amount due to the above-mentioned reverse transfer to the photoconductor becomes relatively large with respect to the toner amount finally transferred to the recording paper.

[ACS OFF Mode] Therefore, in the present invention, in order to allow the operator to give priority to image quality over copy speed, the operation unit 800 (FIGS. 4 and 7) causes the above-mentioned AC
When the S function is turned off and the full-color image forming mode is designated, the image forming sequence is executed so that the K image forming order is the last. In the image forming process for the first color, the color processing circuit 303 of the basic image processing circuit 300 is set with the color processing parameter for calculating the print image data for cyan, and the printer module 400 activates the C developing device. The M, Y, and K images are sequentially formed, superposed on the intermediate transfer member, transferred to a recording sheet, and fixed to complete a copy image.

In this mode, that is, in the ACS OFF mode, it is premised that the original is a color image.
By setting the UCR processing parameter for the area that is a grayscale image at a low value, for example, 50%, the highlight area is smoother and the shadow area is deeper than when set to 100%. It can also be configured to form various images.

Here, the influence on the copy image by changing the image forming order will be described. It has already been explained that the earlier the image forming order is, the more the amount of the toner finally transferred to the recording paper is reduced (loss) due to the reverse transfer of the toner to the photoconductor. Therefore, due to the change of the image forming order, the color components whose image forming order is delayed have less toner loss and the image becomes dark. On the other hand, the color components whose image formation order is faster cause a large loss of toner, resulting in a light image. Therefore, in the present invention,
Correction for this change in image density is performed.

Before explaining the correction, the signal flow in the basic image processing circuit 300 will be described with reference to FIG. The image data read by color separation into RGB by the scanner device (207, 250) is input to the scanner γ conversion circuit of the basic image processing circuit 300 and the specific original image detection circuit 500. As described above, the specific original image detection circuit 500 detects a specific image such as banknotes or securities whose copying is prohibited. The scanner γ conversion circuit converts the reading characteristics of the scanner and corrects the difference in characteristics between RGB. The image data that has undergone the scanner γ conversion is processed by the image area automatic separation circuit / color original automatic detection circuit (3
10/320) and the delay memory. Since the color original automatic detection circuit 320 shares the color determination signal output from the image area automatic separation circuit 310, both circuits are integrated here. The delay memory is a circuit for matching the recording image signal processing and the timing of the image area signal output from the image area automatic separation circuit 310. The extended IPU circuit is
This is a circuit for editing and processing images. The spatial filter 1 is used for correction of the MTF of the input system and smoothing processing for removing noise.

The color processing circuit 303 is a color conversion circuit 303e.
And the UCR / UCA processing circuit 303f, and converts RGB image data of the input system into YMCK image data of the recording system. The spatial filter 2301 is used for YMCK image data, such as sharpening adjustment and smoothing processing for noise removal. Next scaling circuit 302
Performs enlargement / reduction processing in the main scanning direction. Finally, in the gradation processing circuit 304 composed of the printer γ conversion circuit 304a and the dither processing circuit 304b, it is converted into a 4-bit recording image signal and passed through the SCSI-I / F (communication unit interface). Printer module 4
00.

The CPU rewrites the parameters of these image processing circuits and receives detection signals and the like output from the image processing circuits via the CPU peripheral circuits. Also C
The PU is also connected to the SCSI-I / F and can communicate with the system control module 600. The PU receives the image processing mode and image adjustment information supported by the operator from the system control module. The desired image processing parameter can be set in the corresponding circuit.

In the present invention, the difference in color reproducibility due to the difference in image forming order is corrected by changing the parameters of the gradation processing circuit 304 and / or the color processing circuit 303.

[Printer γ Conversion Circuit 304a: FIG. 20-
22] FIG. 20 shows the configuration of the printer γ conversion circuit 304a. D-flip-flop and RAM or ROM
The input image data Xin can be immediately converted into desired image data Xout by referring to the contents of the memory table (γ conversion table) LUT1. The memory table LUT1 can store a plurality of γ conversion tables (groups of γ conversion data), and the signal SEL is a selection signal of this table and corresponds to the processing mode, color, density adjustment value and the like. Memory table L
When the UT1 is composed of RAM, one set of reference table is stored in the ROM or program, and the data of the reference table is converted by the control data from the CPU and rewritten into an arbitrary γ conversion table. It is also possible to write in the RAM, and it is possible to realize the γ conversion characteristic as needed even with a small memory capacity.

In FIG. 21, the image forming order of K is the first (1) and the fourth.
The γ conversion characteristics in the second case (2) are shown. Here, the horizontal direction shows the image data before conversion and the vertical direction shows the image data after conversion. Both input and output are 8-bit data, and the larger the value, the darker the image density (the greater the amount of toner adhesion) is recorded. It When the fourth image is formed, the toner loss in the entire image forming process is smaller than when the first image is formed. In 2), conversion is performed so that the density becomes relatively low.

In the present invention, the change of the image forming order is such that K is the largest and CMY is only shifted by 1. Therefore, the correction of the γ conversion characteristic only for K has a considerable effect, but is better. In order to obtain image quality, it is desirable that CMY be also corrected according to the image forming order. Similar to the example of K shown in FIG. 21, two γ conversion tables are prepared for CMY as well, and selection is made according to the mode in which the image formation order is early or late.

A method of reducing the information amount of this conversion table will be described with reference to FIG. FIG. 22A shows a basic correction curve in a standard mode (for example, a mode of forming images in the order of CMYK). This curve has correction characteristics peculiar to each color and gradation mode (dither pattern). In a system having four CMYK colors and two gradation modes for character images and grayscale images, there are eight kinds of curves. Basic correction curve is required. FIG. 22B shows a forward correction curve for correcting the deviation of the γ characteristic when the image forming order is changed, and is used commonly for each color and each gradation mode. FIG. 22C is a total correction curve obtained by combining the basic correction curve and the forward correction curve. The basic correction curve is Xout = f1 (Xin),
When the forward correction curve is Xout = f2 (Xin), the total correction curve is obtained by Xout = f2 [f1 (Xin)].

The CPU calculates an appropriate correction curve according to the instructed processing condition and sets it in the memory table LUT1 of the γ conversion circuit 304a. With such a configuration, it is sufficient to have conversion table data for the total of each type of the basic curve (a) and the forward correction curve (b), and it is not necessary to have conversion table data for the number of combinations of both, and the CPU The amount of memory to be managed can be reduced.

[Color conversion circuit 303e: FIGS. 23 and 24]
FIG. 23 shows a calculation formula for the color conversion process. Here, the color correction calculation is performed by the primary masking process. To calculate the data for one color of the recording system,
Three multiplications and three additions are required.

FIG. 24 shows the configuration of a circuit for performing this calculation, that is, the color conversion circuit 303e. This circuit 3
03e includes D-flip-flops FF4 to FF3 and 3
Number of multipliers MUL1 to 3 and one 4-input adder AD
It is composed of D. The coefficient register REG is a register for temporarily storing A1 to A4 of the calculation formula shown in FIG. 23, and is rewritten by the control of the CPU according to the change of the color to be calculated or the processing mode. The SEL signal is RGB
Is a hue signal indicating the magnitude relation of the color correction coefficient, and is configured so that an optimized color correction coefficient corresponding to a plurality of hues can be selected, and more suitable color correction processing can be performed.

[Color Conversion Circuit 303: FIG. 25] FIG. 25 shows the configuration of the color processing circuit 303. The color processing circuit 303
In addition to the D-flip-flops FF9 and FF10, the color conversion circuit 303e (CC1) and UCR / U shown in FIG.
It is composed of a CA processing circuit 303f. UCR / UCA
The processing circuit 303f is composed of a circuit CC2 for calculating a UCR amount and a UCR / UCA processing memory table LUT. The UCR amount calculation circuit CC2 includes a color conversion circuit 303.
The circuit has the same configuration as e (CC1), and the coefficient is set so as to calculate data proportional to the minimum value of RGB. The LUT includes a UCR process for subtracting the UCR data calculated by the UCR amount calculation circuit CC2 from the color correction data calculated by the color conversion circuit 303e (CC1);
8 is a memory table that simultaneously performs UCA processing for adding color component amounts according to R amounts in a table reference expression. The data in this table can also be rewritten under the control of the CPU, and the UCR / UCA characteristics can be changed according to preference.

In this color processing circuit 303, if the color correction coefficient is multiplied by a constant and reset, the output value is multiplied by a constant. That is, the toner adhesion amount that changes according to the image forming order can be adjusted by adjusting the value of this constant. Further, if the order of color superposition is changed by changing the image forming order, the color expression characteristic of the recording system is changed due to the difference in toner transparency and the difference in transfer efficiency. It is possible to considerably improve the color reproducibility by correcting the γ conversion characteristics described above, but it is more preferable to select and set the color correction coefficient that is optimized according to the combination of the image forming order. A copy image with excellent color reproducibility can be obtained.

[Correction of Toner Adhesion Amount by Correcting Control Condition of Image Forming Process: FIG. 26] As a method of correcting the toner adhesion amount, there is a method of correcting the control condition of the image forming process. FIG. 26 shows the relationship between the development potential, which is a control parameter of the developing process in the image forming process, and the toner adhesion amount γ characteristic on the photoconductor. FIG. 26A shows the charging potential V _D of the photoconductor, the exposure portion potential V _L and the developing bias V _B.
3 shows the relationship between the toner adhesion part and the toner adhesion part. here,
Negative / positive development is used to visualize the exposed portion of the photoreceptor whose potential has dropped with toner. Here the V _B -V _L of the development potential V _GP.

FIG. 26B shows the relationship between the surface potential of the photosensitive member and the toner adhesion amount. It can be seen that the toner adhesion amount is increased or decreased by changing V _L when V _B is used as a reference. That is, the toner adhesion amount can be increased or decreased by increasing or decreasing V _GP . V _K is a development start potential, and generally development starts from a potential lower than V _B. Therefore, V _D is V
It is necessary to set it lower than _K , and if this difference is small, background stains are likely to occur. When controlling the adhesion amount by adjusting V _GP , it is desirable to set not only _VL and V _B but also V _D , while appropriately setting a margin for background contamination.

In consideration of this fact, FIG. 26C shows V
_It is a graph of a potential setting table for adjusting _GP continuously. In practice, 20 to 20 of these
Combination data of set values of about 50 points is held, and an optimum pointer is selected in accordance with the environment, changes in the photoconductor and the developer over time. Furthermore, the amount of adhesion can be corrected by shifting the selected value of the potential pointer by a fixed number according to the setting of the image forming order.

As described above, the correction of the printer γ conversion table, the correction of the color conversion coefficient, and the correction of the development potential have been described as the means for correcting the adhered amount. A combination of a plurality of these may be configured to perform more suitable correction.

In the second embodiment of the present invention, the operation timing of the color image automatic detection circuit 320 is variable. That is, it is operated at one of the first operation timing and the second operation timing. The first operation timing is the first image formation (ACS ON mode of the first embodiment) as described above, and K is formed first when this mode is selected. The operation of the following device is as described above. By operating the apparatus at this timing, useless scanning becomes unnecessary and a copy image can be formed at high speed. The second operation timing is during prescanning before image formation. As a result, when a black-and-white image is formed, only K is used for image formation, and when a color image is formed, K image is formed last and CMYK is formed in order, thereby preventing deterioration of K character quality. A copy image with good image quality can be obtained.

Also in this second embodiment, at the same time as the first embodiment described above, the parameters of the printer γ conversion, color conversion, and development potential are corrected to obtain an image of optimized quality in each mode. You can Further this second
In the embodiment, the operator can select the copy speed, image quality or performance by selecting the operation timing (ACS ON mode / prescan mode) of the color automatic detection circuit 320 from the operation unit. However, since the color image automatic detection circuit 320 is made to function in any mode, it is possible to continuously obtain copy images by using the ADF without the operator's hand.

As described above, in the embodiment of the present invention, the recording system is Y.
Although the four colors of MCK are used, blue, red, green, etc. may be used as the color components. The image to be formed is not limited to full color, and may be a two-color system such as K + blue and K + red. The input system is not limited to the RGB system, and the brightness L *,
Other color systems such as chromaticity a *, b *, XYZ, YIQ are also applicable. When the recording system has a small number of colors such as a two-color system, the input system may be a system in which two colors are separated accordingly. For example, when the recording system is K + blue, the input system is a system that is color-separated into Y (brightness signal) and B (blue), and a black-and-white image when both Y and B have similar signal levels, When the level of the B signal is low, it is determined that the image is a color image, and images are formed with only K and two colors of KB, respectively. It goes without saying that the correspondence between the separated colors and the recorded colors does not have to be the same. Further, although the scanner is used as the input means, the present invention is also applicable to a device such as a FAX that is input through a communication line and a device that is read and input from an electronic file such as an optical disk or a magnetic disk.

As described above, in the first embodiment, the K single color recording / color recording selection function based on the discrimination between the self-black image and the color image by the color document automatic detection circuit 320 is turned on (ACS ON). Mode), it is discriminated whether the input image data color-separated into three types of color components includes a black-and-white image or a color image, K is formed first, and the color original is automatically detected. When the K single-color recording / color recording selection function based on the discrimination between the self-black image and the color image by the circuit 320 is OFF and the image formation in a plurality of colors including K is selected, the K image formation order is the second or later. System control module
The copy processing CP of the module 600 is the printer module 400.
Since the image formation is controlled, the operator can select image quality, operability, or convenient performance.

In the printer module 400, since a plurality of images to be formed are superposed on the intermediate transfer member,
Images can be formed on various types of recording paper including thick paper and OHP sheets.

The color original automatic detection circuit 320 determines whether the image data color-separated into three components includes a black-and-white image or a color image, and when it is determined that it is not a black-and-white image, or a color original automatic detection circuit. When the K single color recording / color recording selection function based on the discrimination between the self-black image and the color image by 320 is OFF and the image formation is selected with a plurality of colors, the image is formed by using the developing means of KCMY. You can choose the image quality or operability that suits you best.

When the K single color recording / color recording selection function based on the discrimination between the self-black image and the color image by the color document automatic detection circuit 320 is OFF and image formation in a plurality of colors including K is selected, K is selected. Since the copying process CP of the system control module 600 controls the image formation of the printer module 400 so that the image formation order is the last, black characters can be reproduced with good quality.

According to the above-described second embodiment, the color document automatic detection circuit 320 discriminates whether the image data which is color-separated into the input three color components includes a monochrome image or a color image, When the function of selecting one of K single-color recording / color recording based on this identification is made to function at the timing of the first image formation (first timing), K is formed first,
When functioning without image formation at the prescan, that is, at the second timing, K is imaged after the second image, so that the operator can select image quality, copy speed, or convenient performance.

Also in the second embodiment, since a plurality of images to be formed are superposed on the intermediate transfer member, the images can be formed on various recording papers including thick papers and OHP sheets.

Also in the second embodiment, it is discriminated whether the image data separated into the three components contains a black-and-white image or a color image, and if it is discriminated that the image data is not the black-and-white image, an image is formed by using the developing means of KCMY. Therefore, the operator can provide a full-color image forming apparatus in which image quality or operability can be selected conveniently.

Also in the second embodiment, when the K single color recording / color recording selection function based on the discrimination between the self-black image and the color image by the color document automatic detection circuit 320 is made to function at the first timing, Image K first, second
When K is made to function at the timing of, K is imaged last, so that when the operator selects the second timing, the quality of the black character image can be reproduced best.

In both the first and second embodiments described above, the basic image processing circuit 300 (the CPU thereof)
However, since the image processing conditions are changed according to the order of image formation, it is possible to perform image processing with optimum parameters according to the characteristics of each mode, and it is possible to obtain a good reproduced image.

In both the first and second embodiments described above, the γ correction data and / or the color correction data are changed in accordance with the image forming order, so that especially the gradation or /
Also, a reproduced image with good color reproducibility can be obtained.

In both the first and second embodiments described above, the image forming process control conditions are changed according to the image forming order, so that the image forming process is executed under the optimum conditions according to the characteristics of each mode. It is possible to obtain a good image.

In both the first and second embodiments described above, the developing potential is changed according to the order of image formation, so that a reproduced image having particularly good gradation and / or color reproducibility can be obtained. it can.

[Brief description of drawings]

FIG. 1 is a block diagram showing three examples of an image processing system, FIG. 1A shows a combination of a scanner module 200 and a host computer, and FIG. 1B is a printer module 400 and a host (computer). And a facsimile, etc.), and (c) shows a scanner module 200 + printer module 400 + system control module 600 which is an embodiment of the present invention.

FIG. 2 is a block diagram showing another two examples of the image processing system, and FIG. 2D is a scanner module (200-1 to 200-3) + printer module 400+ which is an embodiment of the present invention. Shows a system control module 600,
(E) is a scanner module 2 which is an embodiment of the present invention.
00 + printer module 400 + system control module 600 + host (computer, facsimile, etc.)
Indicates.

FIG. 3 is a block diagram showing an outline of an electric circuit configuration of a scanner module 200 constituting one embodiment (FIG. 3 + FIG. 4 + FIG. 5) of the present invention.

FIG. 4 is a block diagram showing an outline of an electric circuit configuration of a system control module 600 which constitutes an embodiment (FIG. 3 + FIG. 4 + FIG. 5) of the present invention.

5 is a block diagram showing an outline of an electric circuit configuration of a printer module 400 which constitutes an embodiment (FIG. 3 + FIG. 4 + FIG. 5) of the present invention.

6 is a vertical cross-sectional view showing an outline of the mechanism of the scanner module 200 shown in FIG.

FIG. 7 is a system control module shown in FIGS. 4 and 5;
FIG. 3 is a vertical cross-sectional view showing the outline of the mechanisms of a printer 600 and a printer module.

8 is a vertical sectional view of a multi-stage sheet feeding device 480 on which the printer module 400 shown in FIG. 7 is placed.

9 is a time chart showing an outline of operation timings of the scanner module 200 and the system control module 600, and an image reading timing of the scanner module 200. FIG.

10 is a CPU of the scanner controller 230 shown in FIG.
It is a flowchart showing the processing function of.

11 is a CPU of the scanner controller 230 shown in FIG.
It is a flowchart showing the processing function of.

12 is a time chart showing an outline of operation timings of the printer module 400 and the system control module 600, and an image recording timing of the printer module 400. FIG.

13 is a CPU of the printer controller 430 shown in FIG.
It is a flowchart showing the processing function of.

14 is a CPU of the printer controller 430 shown in FIG.
It is a flowchart showing the processing function of.

15 is a CPU of the system controller 630 shown in FIG.
It is a flowchart showing the processing function of.

FIG. 16 is a system control module 600 and a scanner module 20 in the image processing of the color copying mode.
0 is a time chart showing the timing of various processes of 0 and the printer module 400.

FIG. 17 is a time chart showing the timings of various processes of the system control module 600 and the printer module 400 in the image processing of the color print mode.

FIG. 18 is a system control module when an abnormality (paper jam) occurs during image processing in color print mode.
6 is a time chart showing the timing of various processes of the module 600, the scanner module 200, and the printer module 400.

19 is a block diagram showing a configuration of a basic image processing circuit 300 shown in FIG.

FIG. 20 is a printer γ conversion circuit 304a shown in FIG.
FIG. 3 is a block diagram showing the configuration of FIG.

21 is a graph showing conversion characteristics by the γ conversion table LUT1 shown in FIG. 20, where the horizontal axis represents the density represented by the input image data and the vertical axis represents the density represented by the output image data.

22 (a) is a γ conversion table LU shown in FIG.
The basic correction curve that determines the conversion characteristics by T1 is (b)
3 is a graph showing a forward correction curve, and (c) is a graph showing a total correction curve.

23 is a chart showing a color conversion calculation formula of the color correction circuit 303e shown in FIG.

FIG. 24 is a block diagram showing a configuration of a color correction circuit 303e shown in FIG.

25 is a block diagram showing a configuration of a color processing circuit 303 shown in FIG.

FIG. 26A is a graph showing the charging potential V _D , the exposure portion potential V _{L, the} developing bias V _B and the developing potentiometer V _GD of the photoconductor 414 of the printer module 600 shown in FIG. The axis is the circumferential position of the photoconductor 414.
(B) is a graph showing the relationship between the surface potential (horizontal axis) of the photoconductor 414 and the toner adhesion amount (vertical axis). (C) is the surface potential (vertical axis) of the photoconductor, the charging potential V _D , the exposed portion potential _VL
6 is a graph showing the relationship between the developing bias V _B and the required developing potentiometer V _GD (horizontal axis) corresponding to these.

[Explanation of symbols]

180: Manuscript 190A-1
90C: Recording paper 200: Scanner module 201: Power supply circuit 207: Color imaging device 230: Scanner controller 230 SCSI: First communication unit 230 SYNC: First synchronization signal generator 211: Carriage home sensor 300: Basic image processing circuit 400: Printer module 400 img: Image forming mechanism 401: Power supply circuit 414: Photosensitive drum 415: Intermediate transfer belt 426: Image leading edge sensor 430: Printer controller 430 SCSI: Second communication unit 430 SYNC : Second synchronization signal generator 600: System control module 630: System controller 630 SC
SI: 3rd communication unit 650: C of the application processor 650
P: Copy process PR of 650: Print process

Claims (6)

[Claims] 1. In a color image forming apparatus for forming a color image with a first number of plural colors including black (K) by using an electrophotographic process, color separation is performed into a second number of plural color components. Means for inputting image data, an image color identification means for identifying whether the input image data includes a monochrome image or a color image, means for turning on / off the function of the image color identification means, and the image color identification Black (K) is set to 1 when the function of the means is ON.
A color image including a control unit that sets the image forming order of black (K) to the second or later when the image is formed second and when image formation in a plurality of colors including black (K) is selected when OFF. Forming equipment. 2. A color image forming apparatus for forming a color image with a first number of a plurality of colors including black (K) by using an electrophotographic process, wherein color separation is performed into a second number of a plurality of color components. Means for inputting image data, an image color identification means for identifying whether the input image data includes a black-and-white image or a color image, means for switching the timing at which the image color identification means operates, and the image color identification means Control means for forming a black (K) image firstly when operating at the first timing, and for forming a black (K) image after the second image when operating at a second timing. A color image forming apparatus characterized by the above. 3. The first number forming an image is 4, the plurality of colors other than black (K) are cyan (C), magenta (M) and yellow (Y), and the second number is 3. The color image forming apparatus according to claim 1, wherein 3 is 3. 4. The control means selects black (K) when the image color identification function is OFF and an image is formed in a plurality of colors including black (K).
4. The color image forming apparatus according to claim 1, wherein the image forming order is the last. 5. The color image forming apparatus according to claim 2, wherein the control means forms the image of black (K) last when the image color identification means is caused to function at the second timing. 6. The color image forming apparatus according to claim 1, claim 2, claim 3, claim 4, or claim 5, wherein the control means changes the image processing conditions according to the order of image formation.