JPH10285312A - Color image-forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the productivity of copying and the durability of the device, while suppressing cost increase. SOLUTION: A main control section 61 allows a data bus control section 81 to output R, G, B image signals from a scanner 1 to a color correction section 84 as they are and also to memory control sections 82R, 82G, 82B to be once stored in image memories 83R, 83G, 83B and allows the memory control sections 82R, 82G, 82B to read the R, G, B image signals in the image memories 83R, 83G, 83B and to output them to the color correction section 84. Or the data bus control section 81 outputs the R, G, B image signals from the scanner 1 to both the color correction section 84 and the memory control sections 82R, 82G, 82B or only to the color correction section 84 depending on the size of the original.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a color image forming apparatus such as a digital color copying machine, a color facsimile machine, or a multifunction machine integrating them.

[0002]

2. Description of the Related Art As a color image forming apparatus as described above, for example, a scanner (image reading means) scans an image surface of a document to read a full-color data component, and
(Red), G (green), and B (blue) image signals are output, and the image processing unit (image processing means) outputs the image signals to K (black), C (cyan), and M (magenta). ) And Y (yellow) after performing image processing including a process of converting to an image signal for forming a full-color image, and based on the image signal, a printer (image forming means) places K, C, and M on an image carrier. , Y are superimposed to form a full-color image.

Here, the scanner and the color conversion circuit in the image processing section will be described more specifically. The scanner scans the lower surface (image surface) of a document set on a contact glass by moving a traveling body integrated with a mirror, a light source, and the like, and, for example, reflects reflected light images from the document surface on various mirrors. Then, the light enters the color line sensor via the lens.

The color line sensors are R, G, B
And a CCD (light receiving element). The reflected light image from the lens is formed on the light receiving surface of each CCD through each color filter, and converted into R, G, B image signals and output. . This is a known technique used in digital color copying machines.

[0005] The color conversion circuit in the image processing unit includes, for example, R,
The G and B image signals are converted into K, C, M and Y image signals as shown in the following (1) to (4). in this case,
The scanner performs a scan operation four times for one document.

(1) K conversion parameters from the main control unit are set, and the R, G, and B image signals output by the first scanning operation from the scanner are converted into K image signals using the K conversion parameters. Convert. (2) The setting is changed to the C conversion parameter from the main control unit, and the R, G, and B image signals output by the second scanning operation from the scanner are converted into the C image signal using the C conversion parameter. .

(3) The setting is changed to the M conversion parameter from the main control unit, and the R, G, and B image signals output by the third scanning operation from the scanner are converted into the M image signal using the M conversion parameter. Convert to (4) The setting is changed to the Y conversion parameter from the main control unit, and the R, G, and B image signals output by the fourth scanning operation from the scanner are converted into the Y image signal using the Y conversion parameter. .

However, the fact that a scanner performs a scanning operation on a single document four times means that it takes a lot of time just to make one full-color copy, resulting in low copy productivity. In addition, the life of the device is shortened.

In order to solve the problem, for example, R, G, and B image signals output from a scanner by one scanning operation are converted into K, C, M, and Y signals by respective color conversion circuits of an image processing unit. After performing image processing including a process of batch conversion into image signals, the respective image signals are collectively stored in an image memory (image storage means), and then the respective image signals are sequentially sent to a printer to be transferred to an image holding member. There is also a color image forming apparatus that forms a full-color image on a computer.

In such a color image forming apparatus, the number of full-color copies can be obtained by performing a single scanning operation on one document, so that the productivity of the copy and the durability of the apparatus are remarkably increased. However, not only the image memory is added, but also the image signals of R, G, and B are converted to K,
Since the image signals must be converted into C, M, and Y image signals at one time, a color conversion circuit is required four times as much as that of the above-described color image forming apparatus, and the cost of the entire apparatus is greatly increased. There's a problem. In order to solve the problem, a color image forming apparatus as disclosed in, for example, JP-A-3-274854 has been proposed.

In such an image forming apparatus, the R, G, B image signals output by the first scanning operation (scanning) of the reading unit (scanner) are converted into masking units (K, K).
Y, M, and C).
After performing processing such as conversion into M and C image signals, the K image signal is directly sent to a writing unit (printer) to form a K image, and the Y image signal is temporarily stored in an image memory. When the storing (writing) and the image formation of K are completed (when the reading unit starts the return operation), the Y image signal stored in the image memory is sent to the writing unit and
Is formed.

Then, after performing processing such as converting the R, G, and B image signals output by the second scanning operation of the reading section into K, Y, M, and C image signals again by the masking section, The M image signal is sent directly to the writing section to form the M image, and at the same time, the C image signal is temporarily stored in the image memory, and the C image signal stored in the image memory when the M image formation is completed. Is sent to the writing unit to form the image C.

[0013]

In such a color image forming apparatus, it is only necessary to store an image signal for one color in an image memory.
Since a color conversion circuit for collectively converting the image signals into Y, M, and C image signals is used, the cost of the entire apparatus also increases. Further, since it is necessary to perform two scanning operations for one document, the productivity of copying and the durability of the apparatus are slightly reduced.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to suppress an increase in cost and improve the productivity of copying and the durability of the apparatus in a color image forming apparatus.

[0015]

In order to achieve the above object, the present invention provides an image reading means for performing a scanning operation of scanning an image surface of a document to read a full-color data component and outputting an image signal; Image storage means for storing an image signal of at least half the maximum image size from the means, and processing for converting an image signal from the image reading means or the image storage means into an image signal for full-color image formation. Image processing means for performing image processing and outputting, image forming means for forming a full-color image by superimposing images of a plurality of colors on an image carrier based on image signals from the means, and image from image reading means Control for outputting a signal to the image storage means or the image processing means or control for outputting the image signal from the image storage means to the image processing means is selectively performed. To provide a color image forming apparatus that includes a force control means.

A document size discriminating means for discriminating the document size is provided, and the output control means outputs an image signal from the image reading means in accordance with the discrimination result to both of the image storing means and the image processing means or only to the image processing means. It is good to output to. Further, a document replacement presence / absence determining means for determining whether or not the document is replaced when an image formation start instruction is given, and a scanning operation by the image reading means or an image signal stored in the image storage means based on the determination result by the means. Operation determining means for determining which of the above read operations is to be executed.

Still further, an image rotating means for rotating an image signal at the time of writing operation or reading operation to the image storage means, a document size / direction determining means for determining a document size and a direction, and according to a determination result by the means. Rotation execution determination means for determining whether the image rotation means rotates the image signal. In this case, it is preferable to provide a parameter determination unit that determines parameters related to image processing of the image processing unit in accordance with the result of the determination by the rotation execution availability determination unit.

A plurality of paper feed trays, paper size / direction determining means for determining the paper size and direction in each paper feed tray, and presence / absence of paper in each paper feed tray. Paper presence / absence determination means, and when the paper is determined to have run out of paper in the paper feed tray being fed, sheets of the same size and different directions are stored based on the determination result by the paper size / direction determination means. Other tray presence / absence determining means for determining the presence / absence of another paper feed tray, and paper feed changing means for changing to paper feed from the paper feed tray when the means determines that the paper feed tray is present. And an image rotation unit for rotating the image signal stored in the image storage unit by 90 degrees or 270 degrees when the paper supply is changed by the unit.

In the color image forming apparatus of the present invention, the output control means outputs the image signal from the image reading means to the image processing means as it is, or outputs the image signal to the image storage means and temporarily stores the image signal. Output to processing means. For example, an image signal input by one scanning operation by the image reading unit is simultaneously output to the image processing unit and the image storage unit.

Thus, for example, the color conversion circuit of the image processing means sets a parameter for K conversion, and converts the R, G, B image signals from the image reading means into K using the parameters.
The image signal is converted into an image signal, another circuit of the image processing means performs other image processing including a process related to a spatial filter on the K image signal, and the image forming means performs image processing on the image carrier based on the K image signal. Form a K image. On the other hand, the image storage means stores the R, G, B image signals from the image reading means.

Thereafter, the output control means outputs the R, G, B image signals from the image storage means to the image processing means. Thereby, the color conversion circuit of the image processing means changes the setting to the C conversion parameter, converts the R, G, B image signals from the image storage means into C image signals using the parameters, and Another circuit performs other image processing including a process related to a spatial filter on the C image signal, and the image forming unit forms a C image on an image carrier based on the C image signal.

Next, the color conversion circuit of the image processing means changes the setting to the parameter for M conversion, and outputs R,
The G and B image signals are converted into an M image signal using the parameters, and another circuit of the image processing means performs other image processing including a process related to a spatial filter on the M image signal. Forms an M image on the image carrier based on the M image signal.

Finally, the color conversion circuit of the image processing means changes the setting to the Y conversion parameter,
The G and B image signals are converted into a Y image signal using the parameters, and another circuit of the image processing means performs other image processing including processing relating to a spatial filter on the Y image signal, and the image forming means Forms a Y image on the image carrier based on the Y image signal. Note that the order of color conversion by the color conversion means is not limited to the order of K, C, M, and Y.

As described above, in this color image forming apparatus, since the image signals (for example, R, G, B image signals) from the image reading means are stored in the image storage means, the memory capacity of the image storage means is changed to full color. The memory capacity of the image storage means for storing image signals for image formation (for example, K, C, M, and Y image signals) can be made smaller, and the image processing means can be provided from the image reading means or the image storage means. Since it is not necessary to convert the image signals into image signals for full-color image formation at once, it is possible to suppress an increase in the cost of the entire apparatus. Further, the number of full-color copies can be obtained by performing a single scanning operation on one document, so that the productivity of the copy and the durability of the apparatus are greatly improved.

Further, a document size discriminating means for discriminating the document size is provided, and the output control means outputs an image signal from the image reading means to both the image storing means and the image processing means or only to the image processing means in accordance with the discrimination result. You can also output. For example, assume that the maximum image size is A3, and the memory capacity of the image storage unit is １ ／ of the maximum image size (A
If the memory capacity is sufficient to store the image signal up to 4), if the image signal output from the image reading means is an image signal of A4 or less, it is output to both the image storage means and the image processing means. By performing a single scan operation on one document, any number of full-color copies can be obtained.

The image signal output from the image reading means is A
3, the image signal cannot be stored in the image storage means. Therefore, by outputting the image signal only to the image processing means, the scanning operation for one document cannot be performed only once. Copies can be made and the usability of the device is improved.

Further, when an image formation start instruction is given, it is determined whether or not the document is replaced. Based on the determination result, either a scanning operation by the image reading unit or a reading operation of the image signal stored in the image storage unit is performed. May be determined, and the determined operation may be performed.

That is, if the original is replaced, the image reading means is caused to perform the scanning operation, and if the original is not replaced (however, the scanning operation must be performed at least once after the power is turned on). When the original is not replaced, a full-color copy of the same original as before can be obtained without the need for the image reading means to perform the scanning operation. Therefore, the processing efficiency is increased, and the productivity of copying and the durability of the apparatus are further improved.

Further, a document size / direction discriminating means for discriminating the document size and direction is provided, and it is determined according to the discrimination result whether or not to rotate the image signal at the time of a write operation or a read operation to the image storage means. For example, when the maximum image size is A3, if the image signal output from the image reading unit is an image signal of A4 or smaller, the image signal is required at the time of writing operation or reading operation to the image storage unit. By rotating the image signal twice according to each image forming color to the image processing means, two identical full-color images can be finally formed on the image carrier in the image forming means. Copy productivity can be further improved. In this case, the image quality of the full-color copy can be improved by determining the parameters related to the image processing of the image processing means in accordance with the above determination result.

A paper size / direction discriminating means which has a plurality of paper feed trays and discriminates a paper size and a direction in each paper feed tray respectively, and judges the presence or absence of a paper in each paper feed tray. Paper presence / absence determination means is provided, and when the paper presence / absence determination means determines that there is no more paper in the paper feed tray being fed, the paper size and direction are determined based on the determination result by the paper size / direction determination means. Judge whether there is another paper tray containing different paper,
If the paper feed tray is present, change the paper feed from the paper feed tray and rotate the image signal stored in the image storage means 90 degrees or 270 degrees to prevent interruption of the repeat copy (job). You can also.

[0031]

Embodiments of the present invention will be specifically described below with reference to the drawings. FIG. 2 is a schematic configuration diagram showing a mechanical section of a digital color copying machine according to an embodiment of the present invention, and FIG. 3 is a partially enlarged view around a photosensitive drum and an intermediate transfer belt shown in FIG.

This digital color copying machine comprises a scanner (image reading means) 1, a printer (image forming means) 2, and an automatic document feeder (automatic document feed means) 40, and a key on an operation unit (not shown). After the necessary copy conditions are set by the operation, when the start key on the operation unit is pressed while the original is set on the contact glass 3 of the scanner 1, a main control unit (not shown) controls the copy operation. Start.

Accordingly, in the automatic document feeder (hereinafter, abbreviated as "ADF") 40, when a document bundle is set on the document table 41, first, only one document is called from the document bundle. The sheet is separated by 42 and fed onto the contact glass 3 of the scanner 1 by the feeding roller 43. Thereafter, the original is sent to a reading position (exposure position) on the contact glass 3 by the transport belt 44 and set. When a document is set at the reading position on the contact glass 3, the main control unit
To start the scanning operation.

The ADF 40 also functions as a document pressing plate (pressing plate). That is, if the user
The document can be set at the reading position on the contact glass 3 by opening the DF 40 upward, and the document can be fixed at the set position by closing the ADF 40.
Therefore, when the start key is pressed while the original is set on the contact glass 3, the main control unit instructs the scanner 1 to immediately start the scanning operation.

When the start of the scanning operation is instructed, the scanner 1 reciprocates the carriage integrated with the illumination lamp 4 and the first mirror 5a in the horizontal direction, so that the lower surface of the original on the contact glass 3 ( The image plane is scanned. Thereby, the reflected light image from the document surface is guided to the lens 6 via the first mirror 5a, the second mirror 5b, and the third mirror 5c, and is formed on the light receiving surface of the color line sensor 7.

The color line sensor 7 converts the image forming light beam into R, G, B image signals, which are full-color data components, and outputs the signals. The R, G, and B image signals are amplified, dark current corrected, shaded, and A / D converted by a signal processing unit (not shown), and output to an image processing unit (not shown).

The full-color data component of the original image is read as luminance Y and color difference Cb, Cr data, or data based on L * a * b * represented by lightness and chromaticity values.
A full-color image signal may be output. Here, L * a * b * will be briefly described. When a color is to be represented by a numerical value, the lightness is set in units of L *, and the chromaticity representing hue and saturation is set in units of a * b *. . a * and b
* Indicates a color direction, a * indicates a red-green direction, and b * indicates a yellow-blue direction.

The scanner 2 has a contact glass 3
It also has a function of detecting the size and direction of the original set above and outputting the detection result to the main control unit as an original size detection signal.

When the scanning operation for the image surface of the document set at the reading position on the contact glass 3 by the scanner 1 is completed, the ADF 40 sends the document from the contact glass 3 by the transport belt 44 and then discharges the document by the discharge roller 45. The sheet is discharged to the tray 46.

The image processing section converts the R, G, B image signals output from the scanner 1 or the R, G, B image signals once written and stored in the image memory and then read out to the K, C, M. , And Y, and outputs the K, C, M, and Y image signals to the laser writing unit 8 (writing unit) of the printer 2.

The printer 2 has a photosensitive drum (image holding member) 9 inside, and a cleaning unit 1 around the photosensitive drum.
0, static elimination lamp 11, charging charger 12, potential sensor 13, K developing unit 14, C developing unit 15, M developing unit 16, Y
A developing unit 17, a developing density pattern detector 18, an intermediate transfer belt (image holding body) 19, and the like are provided.

Each of the developing units 14 to 17 is a developing sleeve 14 a to 17 a which rotates so as to bring the toner into contact with the photosensitive drum 9, and a developing paddle 14 b to 17 b which draws up and stirs the toner to develop the electrostatic latent image. And toner concentration detection sensors 14c to 17c. In this embodiment, the order of writing and development by laser light (the order of forming color images) is K, C, M, and Y.

When the scanning operation by the scanner 1 is completed, the main control section rotates the photosensitive drum 9 of the printer 2 in the direction of arrow A at a predetermined timing, and the surface thereof is uniformly charged by the charging charger 12. A laser beam modulated according to the K image signal by the laser writing unit 8 is irradiated and exposed while performing main scanning in the drum axis direction to form an electrostatic latent image.

Thereafter, when the leading end of the K latent image formed on the photosensitive drum 9 uniformly charged by the charging charger 12 in accordance with the K image signal reaches the developing position of the K developing unit 14, the K The latent image starts to be developed with the K toner by the rotating developing sleeve 14a, and when the rear end of the K latent image passes the development position, the K development is completed, and a K toner image is formed.

The K formed on the photosensitive drum 9
The toner image is intermediately transferred onto an intermediate transfer belt 19 that rotates adjacent to the photosensitive drum 9. This intermediate transfer is performed when the photosensitive drum 9 and the intermediate transfer belt 19 come into contact with each other.
This is performed by applying a predetermined bias voltage to the intermediate transfer roller 20. After that, the residual toner on the photosensitive drum 9 is removed by the cleaning unit 10,
After the charge is removed by the charge removing lamp 11, the charger 12 is charged again.
Charging, laser writing, development,
The cycle following the intermediate transfer and cleaning is repeated.

Thus, the K, M, Y, and C toner images sequentially formed on the photosensitive drum 9 are successively aligned and transferred onto the intermediate transfer belt 19, whereby the four-color superimposed intermediate transfer image is formed. (Full color image) is formed, and it is collectively transferred onto transfer paper. Therefore, when the K process for forming a K toner image on the intermediate transfer belt 19 is completed,
Next, C for forming a C toner image on the intermediate transfer belt 19 is used.
Proceeding to the process, the timing of the start of the writing by the laser writing unit 8 with the laser beam for the C latent image so that the tip of the C toner image coincides with the tip of the K toner image on the intermediate transfer belt 19. Is adjusted.

Similarly, the M step and the Y step are performed,
An intermediate transfer image of four colors is formed on the intermediate transfer belt 19. However, the image forming order is not limited to K, C, M, and Y, and the image forming order is determined in advance according to the characteristics of the toner and the finishing effect of the full-color image finally formed on the transfer paper. Is done. The intermediate transfer belt 19 is
It is stretched around the intermediate transfer roller 20, the driving roller 21, and the driven roller group, and is circulated in the direction of arrow B by a driving motor (not shown).

The belt cleaner 22 includes a brush roller 22
a, rubber blade 22b, and mechanism 2 for contact and separation from belt
Before the intermediate transfer of the first K toner image, the first K toner image is in contact with the intermediate transfer belt 19, but is separated from the belt surface by the contact / separation mechanism 22c when the intermediate transfer is started.

The paper transfer unit 23 includes a paper transfer roller 23
a, a roller cleaning blade 23b, and a mechanism 23c for contacting and separating from the belt. The paper transfer roller 23a is normally separated from the intermediate transfer belt 19, but when transferring the four-color superimposed intermediate transfer image formed on the intermediate transfer belt 19 onto the transfer paper at a time, the transfer paper 23a is timed. Is pressed against the intermediate transfer belt 19, and a predetermined bias voltage is applied to the roller 23a to transfer the intermediate transfer image onto the transfer paper.

When the four-color superimposed intermediate transfer image starts to be transferred onto the transfer paper, the belt cleaner 22 comes into contact with the intermediate transfer belt 19 after the paper transfer by the contact / separation mechanism 22c, and is driven by the brush roller 22a and the rubber blade 22b. Cleaning is performed by collecting the remaining toner.

Thereafter, the transfer paper on which the four-color superimposed intermediate transfer image has been collectively transferred from the intermediate transfer belt 19 is transferred to the transport belt 2.
7, the toner image is conveyed to the fixing unit 28, and the toner image is fused and fixed by the fixing roller 28 a and the pressure roller 28 b controlled to a predetermined temperature, and discharged to the copy tray 29.
A full color copy is obtained.

The paper cassette (paper tray) 30 to
33, transfer papers of different sizes or directions are stored, and the transfer papers are stored in a paper feed cassette storing transfer papers (paper) of the size or direction designated by an operation signal from the operation unit. The paper is fed by the paper feed roller 25 at a predetermined timing, and the leading end thereof is
6 and temporarily stop the intermediate transfer belt 1.
The sheet is re-fed at the timing when the leading end of the four-color superimposed intermediate transfer image reaches the paper transfer position. Reference numeral 34 denotes a manual paper feed tray for OHP paper and thick paper.

FIG. 4 is a block diagram showing a configuration example of a control system of the digital copying machine. The control unit of the digital copying machine includes a main control unit 61, a scanner control unit 62, an image processing unit 63, a laser drive unit 64, an intermediate transfer belt control unit 65, an AC load control unit 66, and the like. The main control section 61 controls the entire digital copying machine as a whole.

The scanner control unit 62 includes the scanner motor 7
1 and the image reading control by the color line sensor 7 is performed, and the R, G, B image signals output from the color line sensor 7 and the signal indicating the output (reading) timing are sent to the image processing unit 63. .

The image processing unit 63 converts the R, G, B image signals from the scanner control unit 62 of the scanner 1 into K,
After converting them into C, M, and Y image signals, and once writing and storing the R, G, and B image signals in an image memory,
Various image processing including a process of reading out at a predetermined timing and converting the image signals into K, C, M, and Y image signals is performed, and the K, C, M, and Y image signals are sent to the laser driving unit 64.

The laser drive section 64 includes a synchronization detection sensor 72
The laser diode 68 in the laser writing unit 8 shown in FIG. 2 is modulated (ON / OFF) in accordance with the synchronization detection signal from the CPU and the image signal of each color from the image processing unit 63,
The laser diode 68 generates laser light modulated according to the image signal. The synchronization detection sensor 72 detects the laser light reflected by a polygon mirror (not shown) in the laser writing unit 8 outside the image forming area before the start of the image formation in order to keep the image formation start position on the photosensitive drum 9 constant. And outputs a synchronization detection signal.

The polygon motor 73 includes a main controller 61
To rotate the polygon mirror at a rotation speed corresponding to the drive signal from the controller. The intermediate transfer belt control unit 65 turns on the belt drive motor 74 in accordance with the drive signal from the main control unit 61 and the timing signal from the mark sensor 50 to start the rotation of the intermediate transfer belt 19, or at a predetermined timing. To turn off the belt drive motor 74 to stop the rotation of the intermediate transfer belt 19.

The AC load controller 66 includes a main controller 61
The power supply to the AC load 75 including the heater incorporated in the fixing roller 28a is controlled in accordance with the drive signal from the controller. The copying process device 76 includes the charging charger 12, each of the developing units 14 to 17, the paper transfer unit 23, and the like.
Drive.

The sequence device 77 is a motor other than the above-described scanner motor 71, polygon motor 73, and belt drive motor 74, a solenoid, a clutch, and the like, and is driven according to a timing signal from the main control unit 61. The operation unit 78 includes a display for displaying display information from the main control unit 61, and keys for inputting various information.

The sensors and switches 79 are various sensors and switches except the color line sensor 7, the synchronization detection sensor 72, and the mark sensor 50. The various sensors include a paper end sensor for detecting the presence or absence of transfer paper in the paper feed cassettes 30 to 33, and a paper feed cassette 30.
A cassette size sensor for detecting each of the cassette sizes (transfer paper size and direction) within .about.33 is included.

FIG. 1 is a block diagram showing a configuration example of the image processing section 63 of FIG. The image processing unit 63 includes a data bus control unit 81, memory control units 82R, 82G, and 82.
B, image memories 83R, 83G, 83B, color correction unit 8
4 and a gradation processing unit 85.

The data bus control section 81 corresponds to the output control means of the first and second aspects, and the main control section 61
(1) to (1) based on instructions (control signals) from
The control shown in (4) is selectively performed. (1) The image signals of R, G, and B from the scanner 1 are transferred to the memory controllers 82R, 82G, and 82B (image memories 83R and 8B).
3G, 83B) and the color correction section 84 at the same time.

(2) Memory control units 82R, 82G, 82
The R, G, and B image signals from B are output to the color corrector 84. (3) The R, G, and B image signals from the scanner 1 are output only to the color corrector 84. (4) The R, G, and B image signals from the scanner 1 and the R, G, and B image signals from the memory controllers 82R, 82G, and 82B are calculated and output to the color corrector 84.

The memory control unit 82R includes a main control unit 61
The writing operation or the reading operation of the R image signal sent from the scanner 1 via the data bus control unit 81 to the image memory 73R is selectively performed based on the control signal from the scanner 1. Further, at the time of the writing operation or the reading operation, the R image signal is rotated by manipulating the memory address as necessary. Further, it has a scaling processing function.

The memory control unit 82G includes a main control unit 61
And selectively performs a write operation or a read operation of the G image signal sent from the scanner 1 via the data bus control unit 81 to the image memory 83G based on the control signal from the scanner 1. Further, at the time of the writing operation or the reading operation, the G image signal is rotated by manipulating the memory address as necessary. Further, it has a scaling processing function.

The memory control unit 82B includes a main control unit 61
The writing operation or the reading operation of the B image signal sent from the scanner 1 via the data bus control unit 81 to the image memory 83B is selectively performed based on the control signal from the scanner 1. Further, at the time of the writing operation or the reading operation, the B image signal is rotated by manipulating the memory address as necessary. Further, it has a scaling processing function.

The image memories 83R, 83G, and 83B store (accumulate) R, G, and B image signals, respectively.
B is a DRAM, and corresponds to the image storage means of the first aspect. The color correction unit 84 converts the R, G, B image signals into K, C,
A color conversion circuit that converts the image signals into M and Y image signals, and an MTF correction circuit that performs processing (MTF correction) on a spatial filter on the K, C, M, and Y image signals from the color conversion circuit are provided. .

Instead of these circuits, an MTF correction circuit for performing MTF correction on the R, G, and B image signals, and R, G, and B image signals from the MTF correction circuit for K,
A color conversion circuit that converts the image signals into C, M, and Y image signals. The gradation processing unit 85 receives K,
Processing such as printer γ correction processing, scaling processing, and dither processing is performed on the C, M, and Y image signals. The color correction section 84 and the gradation processing section 85 function as the image processing means of the first aspect.

Hereinafter, the output control of the full-color copy according to the present invention in the digital copying machine will be described. It is assumed that A3, A4 horizontal, A4 vertical, and B5 horizontal are stored in the paper feed cassettes 30 to 33.

First, the output control of the full-color copy according to the invention of claim 1 in this digital copying machine will be described.
This will be specifically described with reference to FIG. Here, the maximum image size (the maximum size of the toner image that can be transferred to the intermediate transfer belt 19) is A3, and each of the image memories 83R and 83R.
The memory capacity of G, 83B is a memory capacity capable of storing image signals up to the maximum image size.

FIG. 5 is a diagram showing an AD in this digital copying machine.
It is a figure for explaining copy operation (press plate 1 to 1 copy) operation when F40 is used as a press plate. Operation unit 7 in FIG.
When the number of copies (number of copies) “1” is set by the key operation on 8 and the start key on the operation unit 78 is pressed with the original set on the contact glass 3 in FIG. The first main control unit 61 causes the scanner 1 to start a scanning operation of scanning the image surface of the document and outputting R, G, and B image signals.

The R, G, and B image signals from the scanner 1 are transmitted by the data bus controller 81 to the memory controller 8.
2R, 82G, 82B and the color correction unit 84 output. In addition, a write instruction is given to the memory control units 82R, 82G, and 82B. Thereby, the memory control unit 82
The R, 82G, and 82B write and store the R, G, and B image signals sent from the scanner 1 via the data bus control unit 81 to the image memories 83R, 83G, and 83B, respectively (the memory IN in FIG. 5). ).

Further, the main controller 61 controls the color corrector 8
4 is loaded with parameters for K conversion and parameters (filter coefficients) relating to the spatial filter. Thereby,
The color correction unit 84 sets the K conversion parameter and the filter coefficient, and converts the R, G, and B image signals sent from the scanner 1 via the data bus control unit 81 to K.
The image is converted into a K image signal using the conversion parameters,
After performing MTF correction (processing relating to a spatial filter) on the image signal using the above filter coefficients, the gradation processing unit 85
Output to

The gradation processing unit 85 performs a process such as γ correction on the K image signal from the color correction unit 84 in accordance with an instruction from the main control unit 61 and outputs it to the laser driving unit 64 in FIG. Thereby, a K toner image corresponding to the K image signal is finally formed on the photosensitive drum 9 of FIG. 2 (image formation is performed), and the K toner image is intermediately transferred onto the intermediate transfer belt 19. .

Next, the main control section 61 gives a read instruction to the memory control sections 82R, 82G, 82B. Thereby, the memory control units 82R, 82G, 82B
R stored in the image memories 83R, 83G, 83B,
G and B image signals are read out (memory O in FIG. 5).
UT) to the data bus control unit 81. The main control section 61 outputs the R, G, B image signals from the memory control sections 82R, 82G, 82B to the color correction section 84 by the data bus control section 81.

Further, the C conversion parameters are loaded into the color correction section 84. As a result, the color correction unit 84 changes the setting to the C conversion parameter, and the memory control units 82R and 82R.
The R, G, B image signals sent from the G, 82B via the data bus control unit 81 are converted into C image signals using C conversion parameters, and the C image signals are converted using the above filter coefficients. After performing the MTF correction, the gradation processing unit 85
Output to

The tone processing section 85 converts the C image signal from the color correction section 84 into γ based on an instruction from the main control section 61.
It performs processing such as correction and outputs the result to the laser drive unit 64.
As a result, a C toner image corresponding to the C image signal is finally formed on the photosensitive drum 9, and the C toner image is intermediately transferred onto the intermediate transfer belt 19. That is, K
The C toner image is superimposed on the toner image.

Subsequently, the main control section 61 gives a read instruction again to the memory control sections 82R, 82G, 82B. Thereby, the memory control units 82R, 82G, 82
B reads the R, G, and B image signals stored in the image memories 83R, 83G, and 83B, respectively (memory OUT in FIG. 5), and sends them to the data bus control unit 81. The main control section 61 outputs the R, G, B image signals from the memory control sections 82R, 82G, 82B to the color correction section 84 by the data bus control section 81.

Further, the parameters for M conversion are loaded into the color correction section 84. As a result, the color correction unit 84 changes the setting to the parameter for M conversion, and the memory control units 82R and 82R.
The R, G, B image signals sent from the G, 82B via the data bus control unit 81 are converted into M image signals using M conversion parameters, and the M image signals are converted using the above filter coefficients. After performing the MTF correction, the gradation processing unit 85
Output to

The gradation processing section 85 converts the M image signal from the color correction section 84 into γ based on an instruction from the main control section 61.
It performs processing such as correction and outputs the result to the laser drive unit 64.
Thereby, an M toner image corresponding to the M image signal is finally formed on the photosensitive drum 9, and the M toner image is intermediately transferred onto the intermediate transfer belt 19. That is,
The M toner image is superimposed on the K and C toner images.

Thereafter, the main control section 61 gives a read instruction again to the memory control sections 82R, 82G, 82B. Thereby, the memory control units 82R, 82G, 82
B reads the R, G, and B image signals stored in the image memories 83R, 83G, and 83B, respectively (memory OUT in FIG. 5), and sends them to the data bus control unit 81. The main control section 61 outputs the R, G, B image signals from the memory control sections 82R, 82G, 82B to the color correction section 84 by the data bus control section 81.

Further, a parameter for Y conversion is loaded into the color correction section 84. As a result, the color correction unit 84 changes the setting to the Y conversion parameter, and the memory control units 82R and 82R.
The R, G, and B image signals sent from the G, 82B via the data bus control unit 81 are converted into Y image signals using Y conversion parameters, and the Y image signals are converted using the above filter coefficients. After performing the MTF correction, the gradation processing unit 85
Output to

The tone processing section 85 converts the Y image signal from the color correction section 84 into γ based on an instruction from the main control section 61.
It performs processing such as correction and outputs the result to the laser drive unit 64.
As a result, a Y toner image corresponding to the Y image signal is finally formed on the photosensitive drum 9, and the Y toner image is intermediately transferred onto the intermediate transfer belt 19. That is,
The Y toner image is superimposed on the K, C, and M toner images.

When the intermediate transfer of the Y toner image to the intermediate transfer belt 19 is completed,
Since a full-color image of the color (K, C, M, Y) is completed, the full-color image is collectively transferred onto transfer paper fed from any of the paper feed cassettes 30 to 33, and then the transfer paper is fixed. The full-color image is fixed in the unit 28 and discharged to the copy tray 29 as a full-color copy.

Note that the number of copies is “N (N ≧ 2)”.
Is set, the main control unit 61 sets the above-described 1
After controlling the output of one full-color copy, the following control is performed. That is, the memory control units 82R and 82R
G and 82B are again instructed to read. Accordingly, the memory control units 82R, 82G, and 82B read the R, G, and B image signals stored in the image memories 83R, 83G, and 83B, respectively, and output them to the data bus control unit 81.

Next, the main control unit 61 controls the memory control units 82R, 82G, 82 by the data bus control unit 81.
The R, G, and B image signals from B are output to the color correction unit 84, and a K conversion parameter is loaded into the color correction unit 84. Thereafter, the main control unit 61 performs the same control as described above, so that the same full-color copy as the first sheet is finally discharged to the copy tray 29. Therefore, the main control unit 61 repeats the above-described control for the second and subsequent sheets N-1 times, whereby N full-color copies of one document can be obtained.

As described above, the main control section 61 causes the data bus control section 81 to output the R, G, B image signals from the scanner 1 to the color correction section 84 as it is, and at the same time, the memory control sections 82R, 82G, 82B and temporarily store them in the image memories 83R, 83G and 83B, and then store them in the memory controllers 82R, 82G and 82B.
By reading out the R, G, B image signals in the R, 83G, 83B and outputting them to the color correction unit 84, the following effects can be obtained.

That is, the image memories 83R, 83G, 8
In order to store R, G, B image signals in 3B, K, C,
The memory capacity is smaller than that of the image memory that stores the M and Y image signals, and the color conversion circuit provided in the color correction unit 84 converts the R, G, and B image signals into K, C, M, and Y image signals. Since it is not necessary to perform batch conversion, the increase in the cost of the entire apparatus can be suppressed. Further, the number of full-color copies can be obtained by performing a single scanning operation on one document, so that the productivity of the copy and the durability of the apparatus are greatly improved.

Next, the output control of the full-color copy according to the second aspect of the present invention will be described. Here, the scanner 1 and the main control unit 61 also function as a document size determining unit.
The maximum image size is A3, and each image memory 83
R, 83G, 83B memory capacity to 1 of the maximum image size
It is assumed that the memory capacity is sufficient to store an image signal of up to a half size (A4 landscape or A4 portrait). Note that “vertical” indicates the direction of the original and the transfer sheet whose longitudinal direction coincides with the transport direction, and “horizontal” indicates the direction of the original and the transfer paper whose longitudinal direction is orthogonal to the transport direction.

When the number of copies is set to “1” by a key operation on the operation unit 78 and the start key on the operation unit 78 is pressed with the original set on the contact glass 3, the main control unit 61 Causes the scanner 1 to start the scanning operation. Next, the size of the original on the contact glass 3 (the size of the R, G, B image signals from the scanner 1) is determined based on the original size detection signal from the scanner 1.

When the original size is A4 horizontal, A4 vertical, or B5 horizontal, the data bus control unit 81 transmits the R, G, B image signals from the scanner 1 to the memory control units 82R, 82G, 82B ( Image memory 83R, 8
3G, 83B) and the color correction unit 84, and thereafter, the same control as the above-described control according to the first aspect of the present invention is performed.

As a result, finally, the intermediate transfer belt 1
9, a full-color image of K, C, M, and Y is completed. Therefore, the full-color image is transferred from a transfer paper (A4 horizontal, A4 vertical, or B5 horizontal transfer) supplied from any of the paper feed cassettes 30 to 33. After the transfer, the full-color image is fixed on the transfer paper by the fixing unit 28, and the transfer paper is discharged to the copy tray 29 as a full-color copy.

Note that the number of copies is "N (N≥2)".
Is set, the main control unit 61 sets the above-described 1
After performing the output control of the full-color copy of one sheet, a read instruction is given again to the memory control units 82R, 82G, and 82B, and thereafter, the same control as the control according to the first aspect of the present invention is performed. By repeating the control N-1 times, N full-color copies of one document can be obtained.

On the other hand, when the document size is A3, the main control unit 61 causes the data bus control unit 81 to output the R, G, B image signals from the scanner 1 to only the color correction unit 84, The scanner 1 is caused to perform the scanner operation three more times to sequentially output the R, G, and B image signals, and the data signals are sequentially output to the color correction unit 84 by the data bus control unit 81.

As a result, finally, the intermediate transfer belt 1
9, a full-color image of K, C, M, and Y is completed, and the full-color image is collectively transferred onto transfer paper (transfer paper of A3) fed from one of the paper feed cassettes 30 to 33. Thereafter, the transfer paper is fixed with a full-color image by a fixing unit 28 and is discharged to a copy tray 29 as a full-color copy. Note that "N
(N ≧ 2) ”, the main control unit 61
Repeats the above control N times.

As described above, the main control section 61 uses the data bus control section 81 to transfer the R, G, B image signals from the scanner 1 to the memory control sections 82R, 82 according to the document size.
G, 82B and both the color correction unit 84 or the color correction unit 84
The following effects can also be obtained by outputting to only one of them.

That is, if the image signal output from the scanner 1 is an A4 horizontal, A4 vertical, or B5 horizontal image signal, the image signal is output to both the memory control units 82R, 82G, 82B and the color correction unit 84. Thus, it is possible to make any number of full-color copies by performing a single scan operation on one document. If the image signal output from the scanner 1 is an A3 image signal, the image signal is output only to the color correction unit 84, so that the scanning operation for one document does not have to be performed once, but the full-color copy is performed. And the usability of the device is improved.

Next, the output control of the full-color copy according to the third aspect of the present invention will be described. Here, the scanner 1 and the main control unit 61 also function as a document replacement presence / absence determining unit and an operation determining unit. Also, the maximum image size is A3,
The memory capacity of each of the image memories 83R, 83G, and 83B is a memory capacity capable of storing an image signal up to the maximum image size or half the size.

When the number of copies is set to “1” by a key operation on the operation unit 78 and the start key on the operation unit 78 is pressed with the original set on the contact glass 3, the main control unit 61 Is ADF40 (press plate)
The presence / absence of document replacement is determined based on a signal from a sensor (not shown) that detects opening / closing of the document, and the scanning operation by the scanner 1 or the image memory 8 is performed based on the determination result.
It is determined which one of the read operations of the image signals stored in the 3R, 83G, and 83B is to be executed, and the determined operation is executed.

That is, if the document is replaced, the scanner 1 is caused to perform the scanning operation. If the document is not replaced (however, the scanning operation must be performed at least once after the power is turned on). , 82
G, 82B, image memories 83R, 83G, 83B
, The read operation of the R, G, and B image signals stored therein. Hereinafter, the above-mentioned claim 1 or 2
The same control as the output control of the full-color copy according to the invention is performed.

As described above, the main controller 61 controls the ADF
The presence / absence of document replacement is determined based on a signal from a sensor that detects the opening and closing of the pressure plate 40, and based on the determination result, the scanning operation by the scanner 1 or the image signal stored in the image memories 83R, 83G, and 83B is performed. By performing any one of the reading operations, it is possible to make a full-color copy of the same original as the previous one without having the scanner 1 perform the scanning operation when the original is not replaced.

The user sets copy conditions by key operation on the operation unit 78 and makes a full-color copy of the original. The copy image is evaluated, and if the copy image is not as desired, the operation unit 78 It is often the case that the copy conditions are changed by operating the above keys, and a color copy of the same document is made again. In this case, the image memories 83R, 83G, 83
Since the image signals of R, G, and B read from the original are already stored in B, a full-color copy of the same original as the previous one can be obtained by reading and using these. Therefore, processing efficiency increases,
The productivity of copying and the durability of the apparatus are further improved.

Next, output control of full-color copy according to the fourth and fifth aspects of the present invention will be described with reference to FIG. Here, the scanner 1 and the main control unit 61 also function as an image rotation unit, a document size / direction determination unit, a rotation execution determination unit, and a parameter determination unit. The maximum image size is A3, and each of the image memories 83R, 83G,
The memory capacity of 83B is a memory capacity capable of storing image signals up to the maximum image size.

FIG. 6 is a diagram showing the AD in this digital copying machine.
Other copy when F40 is used as a platen (platen 1to
It is a figure for explaining operation (2 copies). Operation unit 78
When the number of copies is set to “2” by the above key operation, and the start key on the operation unit 78 is pressed with the original set on the contact glass 3, the main control unit 61 causes the scanner 1 to perform a scanning operation. To start.

Next, the size and direction of the original on the contact glass 3 are determined based on the original size detection signal from the scanner 1. If the original size is A3, the R, G, The B image signal is transferred to the memory control units 82R, 82G, 82B and the color correction unit 8
4 and then perform the same control as the above-described control according to the first aspect of the present invention, so that two full-color copies of one document can be obtained.

If the document size and direction are A4 length, A
In the case of 4 horizontal or B5, R, R from scanner 1
It is determined whether or not it is necessary to rotate the G and B image signals, and if it is not necessary to rotate (the two full-color images of the original can be formed on the intermediate transfer belt 19 in the current direction). 81, the R, G, B image signals from the scanner 1 are transferred to the memory control units 82R, 82
G, 82B and the color correction unit 84.

The memory control units 82R, 82G, 82
B is given a write instruction. Thereby, the memory control units 82R, 82G, and 82B write and store the R, G, and B image signals sent from the scanner 1 via the data bus control unit 81 to the image memories 83R, 83G, and 83B, respectively. (Memory IN in FIG. 6).

Further, the main controller 61 controls the color corrector 8
4 is loaded with K conversion parameters and filter coefficients. Accordingly, the color correction unit 84 sets the K conversion parameter and the filter coefficient, and
Transmitted from the data bus control unit 81 via the data bus control unit 81,
The G and B image signals are converted into K image signals using K conversion parameters, the K image signals are subjected to MTF correction using the above filter coefficients, and then output to the gradation processing section 85.

Subsequently, the main control section 61 gives a read instruction to the memory control sections 82R, 82G, 82B.
Thereby, the memory control units 82R, 82G, 82B
Reads the R, G, and B image signals stored in the image memories 83R, 83G, and 83B (memory OUT in FIG. 6) and sends them to the data bus control unit 81. The main control section 61 outputs the R, G, B image signals from the memory control sections 82R, 82G, 82B to the color correction section 84 by the data bus control section 81.

The color correction unit 84 includes memory control units 82R and 82R.
The R, G, and B image signals sent from the 2G and 82B via the data bus control unit 81 are again converted into K image signals using the K conversion parameters, and the K image signals are converted using the filter coefficients. After the MTF correction, the image data is output to the gradation processing unit 85.

As a result, a K toner image corresponding to the K image signal is finally formed on the photosensitive drum 9 and the K toner image is formed.
After the toner image is intermediate-transferred onto the intermediate transfer belt 19, the same K toner image as the above-described K toner image is again transferred onto the photosensitive drum 9.
A toner image is formed, and the K toner image is intermediate-transferred onto the intermediate transfer belt 19 (a position that does not overlap with the previously transferred K toner image).

Next, the main control section 61 gives a read instruction twice to the memory control sections 82R, 82G and 82B at predetermined intervals. Thereby, the memory control unit 82
R, 82G, 82B are image memories 83R, 83G, 8
The R, G, and B image signals stored in 3B are respectively read (memory OUT in FIG. 6), and control for sending them to the data bus control unit 81 is performed twice at predetermined intervals. The main control section 61 causes the data correction section 84 to output the R, G, B image signals from the memory control sections 82R, 82G, 82B by the data bus control section 81.

Further, a C conversion parameter is loaded into the color correction section 84. As a result, the color correction unit 84 changes the setting to the C conversion parameter, and the memory control units 82R and 82R.
The R, G, and B image signals transmitted twice from the G, 82B via the data bus control unit 81 at predetermined intervals are converted to C,
The C image signals are sequentially converted to C image signals using the conversion parameters, and the respective C image signals are sequentially converted to MTF signals using the filter coefficients.
After the correction, the image data is output to the gradation processing unit 85.

As a result, a C toner image corresponding to the C image signal is finally formed on the photosensitive drum 9, and the C toner image is formed.
After the toner image is intermediate-transferred onto the intermediate transfer belt 19, the same C toner image as the above-described C toner image is again transferred onto the photosensitive drum 9.
A toner image is formed, and the C toner image is intermediate-transferred onto the intermediate transfer belt 19 (a position not overlapping with the previously transferred C toner image). That is, the same C toner image is superimposed on the two same K toner images.

Subsequently, the main control section 61 gives a read instruction twice to the memory control sections 82R, 82G and 82B again at a predetermined interval. Thereby, the memory control units 82R, 82G, and 82B store the image memories 83R, 83R.
The R, G, and B image signals stored in the G, 83B are read out (memory OUT in FIG. 6), and the control for sending them to the data bus control unit 81 is performed twice at predetermined intervals.
The main control section 61 causes the data correction section 84 to output the R, G, B image signals from the memory control sections 82R, 82G, 82B by the data bus control section 81.

Further, an M conversion parameter is loaded into the color correction section 84. As a result, the color correction unit 84 changes the setting to the parameter for M conversion, and the memory control units 82R and 82R.
The image signals of R, G, and B transmitted twice from the G, 82B via the data bus control unit 81 at predetermined intervals are converted into M signals.
The M image signals are sequentially converted to M image signals using the conversion parameters, and the M image signals are sequentially converted to MTF signals using the filter coefficients.
After the correction, the image data is output to the gradation processing unit 85.

As a result, an M toner image corresponding to the M image signal is finally formed on the photosensitive drum 9 and the M toner image is formed.
After the toner image is intermediately transferred onto the intermediate transfer belt 19, the same M toner image as the above M toner image is again transferred onto the photosensitive drum 9.
A toner image is formed, and the M toner image is intermediate-transferred onto the intermediate transfer belt 19 (a position not overlapping with the previously transferred M toner image). That is, the same K and C of two
The same M toner image is superimposed on each toner image.

After that, the main control section 61 gives a read instruction twice to the memory control sections 82R, 82G, 82B again at a predetermined interval. Thereby, the memory control units 82R, 82G, and 82B store the image memories 83R, 83R.
The R, G, and B image signals stored in the G, 83B are read out (memory OUT in FIG. 6), and the control for sending them to the data bus control unit 81 is performed twice at predetermined intervals.
The main control section 61 causes the data correction section 84 to output the R, G, B image signals from the memory control sections 82R, 82G, 82B by the data bus control section 81.

Further, a parameter for Y conversion is loaded into the color correction section 84. As a result, the color correction unit 84 changes the setting to the Y conversion parameter, and the memory control units 82R and 82R.
The R, G, and B image signals transmitted twice from the G, 82B via the data bus control unit 81 at predetermined intervals are converted into Y,
The Y image signals are sequentially converted to the Y image signals using the conversion parameters, and the respective Y image signals are sequentially converted to the MTF using the filter coefficients.
After the correction, the image data is output to the gradation processing unit 85.

As a result, a Y toner image corresponding to the Y image signal is finally formed on the photosensitive drum 9, and the Y toner image is formed.
After the toner image is intermediate-transferred onto the intermediate transfer belt 19, the same Y toner image as the Y toner image is formed on the photosensitive drum 9 again.
A toner image is formed, and the Y toner image is intermediate-transferred onto the intermediate transfer belt 19 (a position not overlapping with the previously transferred Y toner image). In other words, two of the same K,
The same Y toner image is superimposed on the C and M toner images, respectively.

When the intermediate transfer of the Y toner image to the intermediate transfer belt 19 is completed, two identical full-color images are completed on the intermediate transfer belt 19. After being collectively transferred onto two transfer papers (A4 landscape or B5 landscape transfer papers) sequentially fed from the printer, a full-color image is sequentially fixed on each of the transfer papers by a fixing unit 28, and a full-color copy is obtained. It is discharged to the copy tray 29.

When "N (even number of 4 or more)" is set as the number of copies, the main control section 61 controls the output of the above-mentioned two (first and second) full-color copies. Thereafter, output control of the following third and fourth full-color copies is performed.

That is, the main control unit 61 gives a read instruction twice to the memory control units 82R, 82G, and 82B again at predetermined intervals. As a result, the memory control units 82R, 82G, 82B store the image memories 83R, 8R.
The R, G, and B image signals stored in the 3G and 83B are read out and sent to the data bus control unit 81 twice at predetermined intervals.

The main control unit 61 includes the data bus control unit 8
In step 1, the R, G, and B image signals from the memory control units 82 R, 82 G, and 82 B are output to the color correction unit 84, and the K correction parameters are loaded into the color correction unit 84 again. Thereafter, the main control unit 61 performs the same control as described above, so that the same full-color copy as the first and second sheets is finally discharged to the two-sheet copy tray 29. Therefore, the main control unit 61 repeats the above control N / 2 times, so that a full-color copy of one document
You can take one.

When "3" is set as the number of copies, the main control unit 61 performs the output control of the first two (first and second) full-color copies once, and then performs the control. By performing the output control of one full-color copy described above, three full-color copies of one original can be obtained.

Further, when "N (odd number equal to or greater than 5)" is set as the number of copies, the main control section 61 controls the output control of the first two (first and second) full-color copies described above. After performing the above, the output control of the third and fourth full-color copies is performed (N-1) / 2 times, and the output control of one full-color copy is performed as described above. You can make N copies.

On the other hand, when it is necessary to rotate the R, G, B image signals from the scanner 1 (when the R, G, B image signals are rotated, the main Two full-color images of the original set on the intermediate transfer belt 19 can be formed), and the transfer paper (A4
The presence / absence of another paper cassette containing transfer paper (transfer paper of A4 landscape) having the same size and the same direction as that of the vertical transfer paper is determined. Performs the same control as when A3.

If there is another sheet cassette, the data bus controller 81 transmits the R, G, B image signals from the scanner 1 to the memory controllers 82R, 82G,
82B and output to the memory control units 82R and 82R.
G, 82B is given a write instruction. Thereby,
The memory control units 82R, 82G, and 82B transmit R, G, and R signals transmitted from the scanner 1 via the data bus control unit 81.
The image signals of B are stored in image memories 83R, 83G, and 8 respectively.
Write to 3B for storage. At this time, for example, as shown in FIG.
Write operations are performed in the order of 0, 300,....

Next, the main control section 61 gives a read instruction twice to the memory control sections 82R, 82G and 82B at predetermined intervals. Thereby, the memory control unit 82
R, 82G, 82B are image memories 83R, 83G, 8
The R, G, and B image signals stored in 3B are read out twice at predetermined intervals. At this time, for example, as shown in FIG. 7B, the read operation is performed in the order of addresses 099, 098,... (The order orthogonal to the write operation).

Here, the image memories 83R, 83G, 83
The writing direction and the reading direction of the R, G, and B image signals to B are orthogonal to each other.
R, G, and B image signals to be output can be rotated by 90 degrees or 270 degrees. That is, R, G, and R written to the image memories 83R, 83G, and 83B depend on the document size.
Since the number of pixels of the B image signal is determined, the image memory 8
By manipulating the memory address during a write operation or a read operation to 3R, 83G, 83B, R,
The G and B image signals can be rotated by 90 degrees or 270 degrees.

The main control section 61 has a color correction section 84.
Is loaded with K conversion parameters and filter coefficients.
Thereby, the color correction unit 84 sets the K conversion parameter and the filter coefficient, respectively, and
The R, G, and B image signals transmitted twice from the 2R, 82G, and 82B via the data bus control unit 81 at predetermined intervals are sequentially converted into K image signals using K conversion parameters. Each K image signal is sequentially subjected to MTF correction using the above filter coefficients, and then output to the gradation processing unit 85.

As a result, a K toner image corresponding to the K image signal is finally formed on the photosensitive drum 9, and the K toner image is formed.
After the toner image is intermediate-transferred onto the intermediate transfer belt 19, the same K toner image as the above-described K toner image is again transferred onto the photosensitive drum 9.
A toner image is formed, and the K toner image is intermediate-transferred onto the intermediate transfer belt 19 (a position that does not overlap with the previously transferred K toner image).

Next, the main control section 61 gives a read instruction twice to the memory control sections 82R, 82G, and 82B at predetermined intervals. As a result, the memory control units 82R, 82G, and 82B operate the image memory 8 in the same manner as described above.
The R, G, and B image signals stored in the 3R, 83G, and 83B are read, respectively.

The main control section 61 has a color correction section 84.
Is loaded with parameters for C conversion. Thereby, the color correction unit 84 changes the setting to the C conversion parameter,
The R, G, and B image signals transmitted twice at predetermined intervals from the memory control units 82R, 82G, and 82B via the data bus control unit 81 are sequentially converted to C image signals using the C conversion parameters. Then, each of the C image signals is sequentially subjected to MTF correction using the above filter coefficients, and then output to the gradation processing unit 85.

Thereafter, under the same control as described above, the M and Y image signals are output twice from the color correction unit 84 to the gradation processing unit 85, and finally the full color images of K, C, M and Y are output. Two full-color images are completed on the intermediate transfer belt 19, and their full-color images are sequentially transferred collectively onto two transfer papers (A4 landscape transfer papers) sequentially fed from one of the paper feed cassettes 30 to 33. Thereafter, the full-color images are sequentially fixed on the respective transfer papers by the fixing unit 28, and are discharged to the copy tray 29 as a full-color copy.

Note that the number of copies is "N (N ≧ 3)".
Is set, the main control unit 61 executes
By performing the output control of the full-color copy of the first sheet (first and second sheets) or almost the same control (including the processing related to the rotation of the image signal) as the output control of the one full-color copy described above, the full-color copy of one original is performed. You can make N copies.

As described above, the main control unit 61 controls the image memories 83R, 83G, 83 according to the size and direction of the original.
It is determined whether or not to rotate the image signal at the time of the writing operation or the reading operation to B.
When the image signal output from is an image signal of A4 or less,
The image signal is rotated as necessary during a write operation or a read operation to the image memories 83R, 83G, and 83B, and the image signal is output twice to the color correction unit 84 for each image forming color, and finally the printer By forming two identical full-color images on the intermediate transfer belt 19 in the second 2, the productivity of copying can be further improved.

Here, the original on the contact glass 3 is
The image signal obtained by causing the scanner 1 to perform the scanning operation by replacing the image signal by 0 degrees and the image signal from the scanner 1 by 90
The image signals obtained by rotating by degrees are not the same.
In particular, the MTF often differs between main scanning and sub scanning. In the case of the embodiment, the MTF in the main scanning direction is M
Since it is higher than TF, the processing (MT
It is desirable to perform F correction) in each case.

Therefore, it is determined whether or not to rotate the image signal, and a filter coefficient is determined so that a different spatial filter can be used in accordance with the determination result. By setting, the image quality of full-color copy can be improved. In addition,
For example, the MTF correction circuit is provided with a filter coefficient for normal operation and a filter coefficient for rotation as shown in FIGS. 8A and 8B, respectively, and the main control unit 61 selects one of them according to the above determination result. Or download the filter coefficients themselves to the MTF correction circuit.

When the main control unit 61 controls the output of each full-color copy as described above and the paper feed cassette in which the paper is being fed runs out of paper (when the paper end is reached), the sizes are the same and the directions are different. It is determined whether there is another sheet cassette in which the transfer sheet is stored, and if there is such a sheet cassette, the sheet is fed from the sheet tray and the image memory 8
By rotating the R, G, and B image signals stored in the 3R, 83G, and 83B by 90 degrees or 270 degrees, interruption of the repeat copy can also be prevented.

Further, the rotation of the image signal is stored in the image memory 83.
If the reading operation is performed at the time of reading from R, 83G, and 83B, even when the paper feed cassette is switched, it is not necessary to cause the scanner 1 to perform the scanning operation again, so that the control efficiency is further improved. In this case, the scanner 1, the printer 2, and the main control unit 61 operate according to claim 6.
It functions as a direction discriminating unit, a sheet existence judging unit, another tray existence judging unit, a sheet feeding changing unit, and an image rotating unit.

In this embodiment, the color correction unit 84
However, after converting the R, G, and B image signals into K, C, M, and Y image signals, the MTF correction is performed on the K, C, M, and Y image signals. As a result of the change in the circuit configuration as described above, the R, G, and B image signals
After the F correction, the R, G, B image signals are converted to K,
It can also be converted to C, M, Y image signals.

The embodiment in which the present invention is applied to a digital color copying machine has been described above. However, the present invention is not limited to this, and uses an electrophotographic system such as a digital color facsimile apparatus or a multifunction machine integrating them. It can be applied to a color image forming apparatus.

[0144]

As described above, according to the color image forming apparatus of the present invention, it is possible to suppress an increase in cost and to improve the productivity of copying and the durability of the apparatus.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of an image processing unit 63 in FIG.

FIG. 2 is a schematic configuration diagram showing a mechanism of a digital color copying machine according to an embodiment of the present invention.

FIG. 3 is a partially enlarged view around a photosensitive drum and an intermediate transfer belt in FIG. 2;

FIG. 4 is a block diagram illustrating a configuration example of a control system of the digital copying machine illustrated in FIG. 2;

FIG. 5 shows an ADF4 in the digital copying machine shown in FIG. 2;
It is a figure for explaining copy operation (press plate 1 to 1 copy) operation when 0 is used as a press plate.

FIG. 6 is a view for explaining another copy operation (press plate 1 to 2 copy) when the ADF 40 is used as a press plate.

FIG. 7 is a diagram for explaining a write operation and a read operation to image memories 83R, 83G, and 83B for rotating an image signal to a color correction unit 84 in FIG. 1;

FIG. 8 is a diagram illustrating an example of different coefficients of a spatial filter used in the color correction unit 84 of FIG. 1;

[Explanation of symbols]

 1: Scanner 2: Printer 7: Color line sensor 8: Laser writing unit 9: Photoconductor drum 10: Cleaning unit 11: Static elimination lamp 12: Charger 14: K developing device 15: C developing device 16: M developing device 17 : Y developing device 19: intermediate transfer belt 20: intermediate transfer roller 23: paper transfer unit 23 a: paper transfer roller 40: automatic document feeder (ADF) 61: main control unit 62: scanner control unit 63: image processing unit 64 : Laser drive unit 68: Laser diode 78: Operation unit 79: Sensors and switches 81: Data bus control unit 82 R, 82 G, 82 B: Memory control unit 83 R, 83 G, 83 B: Image memory 84: Color correction unit 85: Tone Processing unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04N 1/387 H04N 1/387

Claims (6)

[Claims] An image reading means for performing a scanning operation for scanning an image surface of a document to read a full-color data component and outputting an image signal, and an image corresponding to at least half the maximum image size from the means. Image storage means for storing a signal; image processing means for performing image processing including processing for converting an image signal from the image reading means or the image storage means into an image signal for full-color image formation; Image forming means for forming a full-color image by superimposing images of a plurality of colors on an image carrier based on an image signal from the apparatus, and outputting an image signal from the image reading means to the image storage means or the image processing means Output control means for selectively performing control for outputting the image signal from the image storage means to the image processing means. A color image forming apparatus. 2. A color image forming apparatus according to claim 1, further comprising: a document size discriminating means for discriminating a document size, wherein said output control means outputs a signal from said image reading means in accordance with a discrimination result by said document size discriminating means. Wherein the image signal is output to both the image storage means and the image processing means or only the image processing means. 3. A color image forming apparatus according to claim 1, wherein a document replacement determining means for determining whether or not the document is replaced when an image formation start instruction is issued, and said image reading based on a determination result by said means. A color image forming apparatus comprising: an operation determining unit that determines which of a scanning operation by the unit and a reading operation of an image signal stored in the image storage unit is performed. 4. A color image forming apparatus according to claim 1, wherein an image rotating means rotates an image signal at the time of a writing operation or a reading operation to said image storage means.
Document size / direction discriminating means for discriminating a document size and direction, and rotation execution determining means for judging whether or not to rotate the image signal by the image rotating means according to the discrimination result by the means are provided. A color image forming apparatus, comprising: 5. The color image forming apparatus according to claim 1, further comprising a parameter determination unit that determines a parameter related to image processing of the image processing unit according to a result of the determination by the rotation execution determination unit. Color image forming apparatus. 6. The color image forming apparatus according to claim 1, further comprising a plurality of paper feed trays, a paper size / direction determining unit for determining a paper size and a direction in each of the paper feed trays, and Paper presence / absence determining means for determining the presence / absence of paper in the paper feed tray; and when the means determines that there is no paper in the paper feed tray being fed, the paper size / direction determination means Means for determining the presence or absence of another paper feed tray containing paper of the same size and in the different direction based on the paper feed tray. Paper feed changing means for changing the paper feed from the tray, and when the paper feed is changed by the means, the image signal stored in the image storage means is turned by 90 degrees or 270 degrees.
A color image forming apparatus provided with image rotating means for rotating the image by an angle.