JP2998723B2 - Color image processing circuit, color image forming apparatus, and color image processing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color image processing circuit having a mosaic monitor function and an image forming apparatus including the same.

[0002]

2. Description of the Related Art A digital color copying machine includes a reading section for reading a document using a color image sensor and converting the read document into a print output signal, and a printer section for printing an image on paper in accordance with the print output signal by electrophotography. When printing out a plurality of colors, the reading unit reads a document and prints an image on the same paper by the printer unit on a color-by-color basis. The reading unit generally includes a masking circuit, and generates a color-corrected signal according to the characteristics of an output device (such as a printer). The color-corrected image is printed in this way, but it is difficult for the masking circuit to keep the color difference between the original and the copy very small for all colors on the original. Therefore, when a copy is copied as a document, the color tone may be significantly changed from that of the document. However, in a limited chromaticity range, a change in color tone can be suppressed relatively small by performing color adjustment (color balance). However, conventionally, color tone adjustment is performed by cutting and trying after making a copy for each color adjustment, and scanning for the number of adjustment times × the number of print colors is repeated, which is wasteful in terms of time and cost. was there.

Accordingly, the present applicant has proposed a color adjustment selection method (hereinafter, referred to as a mosaic monitor) for reducing the time and cost required for color correction in another application. In this method, an area (attention area) including a part (for example, a face) where the user particularly wants to emphasize color reproduction is set by means for setting a specific area, and image data of the attention area is stored in the image memory means. . Next, the image data read from the image memory means is subjected to color correction at various predetermined different color correction levels, and these are copied to different positions on the same sheet in one printing step. The user selects an image closest to the color of the original image or an image of the user's favorite color from the images (mosaic monitor images) of a plurality of regions of interest having different colors copied on one sheet of paper. I do. Next, the entire document is copied based on the color correction level value of the selected image. In this way, a copy with the color adjustment desired by the user can be easily obtained.

[0004]

A copy of the color adjustment desired by the user can be easily made by the mosaic monitor. When performing copying, the density level may be adjusted to an appropriate value corresponding to the original image. Therefore, when entering the mosaic monitor mode, the density level may be different from the standard value. At this time, the mosaic monitor image is also printed at that density level. When the user selects a desired color adjustment by looking at the mosaic monitor image, if the density level is not a standard value, the selection may be erroneous.

It is an object of the present invention to provide a color image processing circuit in which selection of color adjustment in a mosaic monitor mode is less likely to cause an error. It is another object of the present invention to provide a color image forming apparatus in which selection of color adjustment in a mosaic monitor mode is less likely to cause an error. Still another object of the present invention is to provide a color image processing method in which selection of color adjustment in a mosaic monitor mode is less likely to cause an error.

[0006]

A color image processing circuit according to the present invention comprises: an image memory for storing input image data; a color correction means for performing a color correction operation on the image data read from the image memory; Means for inputting a density signal corresponding to the obtained density level, means for setting an output density level at the time of image output based on the density signal, and performing different color correction calculations on specific image data. Input means for inputting a mosaic monitor signal indicating a mosaic monitor mode for outputting a plurality of images adjacent to each other; and when the mosaic monitor signal is input, the output density level is set to a standard value regardless of the input density signal. And control means for performing different color correction operations on the image data read from the image memory and outputting a plurality of image data. To. The input image data is stored in the image memory, and the control unit outputs a plurality of image data based on the image data stored in the image memory in the mosaic monitor mode. Here, the control means automatically sets the density level to the standard value in the mosaic monitor mode. Therefore, a plurality of images in the mosaic monitor mode are processed at a standard density level. Further, a color image forming apparatus according to the present invention includes the above-described color image processing circuit. Preferably, the color image forming apparatus includes a printer unit and print control means for controlling the print density of the printer unit based on the set output density level.

A color image processing method according to the present invention is a color image processing method in a mosaic monitor mode for performing different color correction operations on specific image data stored in an image memory and outputting a plurality of images adjacently. Inputting a density signal corresponding to a set density level, setting an output density level at the time of image output based on the density signal, inputting a mosaic monitor signal indicating a mosaic monitor mode, With the input of the signal, the output density level is set to a standard value irrespective of the input density signal, the same image data is read from the image memory a plurality of times, and subjected to different color correction calculations and output. That is, since the density level is automatically set to the standard value in the mosaic monitor mode, a plurality of images in the mosaic monitor mode are processed at the standard density level.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. (A) Configuration of Digital Color Copier A digital color copier according to the present invention reads a document using an image sensor and converts the document into a print output signal. And a printer unit for printing images. When printing out a plurality of colors, reading of an original by the reading unit and printing of an image on the same paper by the printer unit are performed in a sequential manner for each color. FIG. 1 shows the overall configuration of a digital color copying machine according to an embodiment of the present invention. The scanner 10 includes an exposure lamp 12 for irradiating a document, a rod lens array 13 for collecting light reflected from the document, and a contact type CCD color sensor (image sensor) 14 for converting the collected light into an electric signal. Have. The scanner 10 is driven by the motor 11 to move in the direction of the arrow when reading a document, and scans the document placed on the platen 15. The image of the document surface irradiated by the light source 12 is photoelectrically converted by the CCD color sensor 14.

The R, G, B electric signals (multi-valued) obtained by the CCD color sensor 14 are read by a read signal processing unit 20.
Is converted into a print output signal (binary) of any of yellow, magenta, cyan, and black, and stored in the buffer memory 30. In the print head unit 31, the LD drive circuit 32 blinks the semiconductor laser (LD) 33 in accordance with the print signal from the buffer memory 30 (second).
See figure). As shown in FIG. 1, the laser beam generated by the semiconductor laser 33 exposes the photoconductive drum 41, which is driven to rotate, via the reflecting mirror 37. As a result, an image of the document is drawn on the photoconductor of the photoconductor drum 41. The photoreceptor drum 41 is irradiated by an eraser lamp 42, charged by a charging charger 43, and further irradiated by a sub-eraser lamp 44 before receiving exposure for each copy. When exposure is performed in this state, an electrostatic latent image is formed on the photosensitive drum 41. Only one of the yellow, magenta, cyan, and black toner developing units 45a to 45d is selected to develop the electrostatic latent image on the drum. The developed image is transferred by the transfer charger 46 onto the paper wound on the transfer drum 51.

Normally, such a printing process is repeated for yellow, magenta, cyan and black. At this time, the scanner 10 repeats the scanning operation in synchronization with the operations of the photosensitive drum 41 and the transfer drum 51. Thereafter, the paper is separated from the transfer drum 41 by operating the separation claw 47, is fixed through the fixing device 48, and is discharged to the discharge tray 49. The paper is fed from a paper cassette 50, and the leading end thereof is chucked by a chucking mechanism 52 on the transfer drum 51, so that no positional deviation occurs during transfer. Next, referring to FIG. 2, a signal processing unit 20 that processes an output signal of the CCD color sensor 14 and outputs a binary image signal will be described.

When a normal image is output, an image signal photoelectrically converted by the CCD color sensor 14 is converted into an image density by a log amplifier 21 and then converted into a digital value (multi-value) by an A / D converter 22. Is converted. The multi-value converted R, G, B image signals are output to a shading correction circuit 23.
Then, shading correction is performed. In the mosaic monitor mode or the like, the signal subjected to shading correction is stored in the registered image memory circuit 1. When outputting a normal color image, the registered image memory circuit 1 is canceled, and the signal subjected to shading correction is sent to the masking processing circuit 24.

In the above processing, three colors of R, G and B are processed in parallel. Next, the masking processing circuit 24 generates a signal of one of the printing colors (any of yellow, magenta, cyan, and black) from the three input signals in accordance with the characteristics of the printing toner in order to perform the printing in the frame sequential manner. Which print color is to be generated is determined by a control signal from the CPU 25. When the color adjustment is changed in the mosaic monitor mode or the normal mode, the print signal is subjected to color correction by the image tone setting circuit 2. In the case of a normal image, the image tone setting circuit 2 is canceled and no color correction is performed. The electric scaling circuit 26 electrically processes a signal from the masking processing circuit 24 or the image setting circuit 2 to electrically change the magnification in the main scanning direction. Here, the description is omitted. On the other hand, the magnification in the sub-scanning direction is
This can be realized by making the speed of the relative movement between the original and the scanner 10 variable.

The halftone processing circuit 27 includes an electric scaling circuit 26.
The binary signal is binarized to generate a binary pseudo halftone signal. The LD drive circuit 32 includes the buffer memory 30
The semiconductor laser 33 is driven in accordance with the pseudo halftone signal from the camera to emit a laser beam. The clock generator 28 has a horizontal synchronizing signal Hsy for synchronizing reading of the CCD color sensor 14 and image data processing of each circuit.
nc and a clock signal CKA. In addition, the scaling sub-scanning clock generator 29 generates a scaling sub-scanning clock which is an interrupt signal to the registered image memory circuit 1 in accordance with a signal from the CPU 25. In the signal processing unit 20,
The image data is processed at the timing as shown in FIG.
Here, the horizontal synchronization signal Hsync and the clock signal CKA are
The R, G, and B image data generated by the clock generator 28 and transmitted from the CCD color sensor 14 flows serially in synchronization with the CKA (the numbers of the image data indicate addresses in the main scanning direction in the figure). Each time the horizontal synchronization signal Hsync is generated, the line n in the main scanning direction is updated. That is, the scanner 10 has advanced by a unit distance in the sub-scanning direction.

This digital color copying machine has a color adjustment function called a mosaic monitor and a superimpose function. Since both functions require a memory for storing image data and also have many common points in image processing, the registered image memory circuit 1 for image registration / readout and the image tone setting circuit 2 for color adjustment are shared. , Are controlled by the CPU 25 to realize both functions. Since the superimpose function is disclosed in another application filed by the present applicant,
Detailed description is omitted.

FIG. 4 is a diagram showing an arrangement of various keys and the like on an operation panel 70 provided on the upper surface of the copying machine. The operation panel 70 includes a print start key 71 for starting a copy operation, an interrupt key 72 for designating an interrupt copy, a clear / stop key 73, an all reset key 74, a ten key 75, a set key 76, and a cancel key 77. There are provided various function keys 78 to 81, jog dials 82 and 83 for setting an area to be described later, and a display section 84 composed of a liquid crystal or the like for displaying a document image and displaying various messages for setting an area. I have. Here, the function keys 78, 79, 80
These are a mosaic monitor selection key, a superimpose mode selection key, and a density correction key. The setting of a region such as a region of interest in the mosaic monitor mode described later is performed as follows. For example, when setting the attention area,
As shown in FIG. 5, a document is placed on the platen 15 and a preliminary scan is performed by the scanner 10, whereby the document image is roughly displayed in the document area ED of the display unit 84 of the operation panel 70. The intersection of the vertical and horizontal instruction lines LPY and LPX is the center of the area EA. When the jog dials 82 and 83 are operated, these indicating lines move left and right or up and down, respectively, so that the area EA is determined, and by pressing the set key 76, the attention area is set.

A density correction key 80 is a key for adjusting a copy density by setting and changing a density adjustment coefficient. The density adjustment coefficient can be adjusted in nine steps, for example, as shown in FIG. The level is the standard value at level 5, is higher than the standard value at level 6 or higher, and is lower than the standard value at level 4 or lower.
The density adjustment level is incremented by the number of times the density correction key 80 is pressed, and the selected level (one character from 1 to 9) is displayed on the display unit 84 as inverted characters. A signal corresponding to the level selected from the operation panel 70 is sent to the CPU 25, and the CPU 25 sets a density correction coefficient in accordance with the signal, and changes the amount of charge to adjust the density by changing the amount of toner adhesion. As described later, in the mosaic monitor mode,
Since the density correction coefficient is automatically set to a standard value, it is not used. Therefore, the density correction key 80 functions as a color correction key in the mosaic monitor mode.

(B) Mosaic monitor and color correction adjustment function The mosaic monitor is a registered image memory circuit (see section (d)) 1 for storing a region of interest, and an image setting circuit ((c)) for performing color adjustment in a printing process. Section 2). Function key 78 on operation panel 70
Press to select the mosaic monitor mode. The mosaic monitor indicates a region of interest where the user wants to perform color reproduction best, and the image of the region of interest is printed simultaneously on the same paper in various colors according to the instruction. This is a color adjustment selection method for selecting an optimum color tone from among the mosaic monitor images) and monitoring the color tone so that the optimum color adjustment is obtained from the mosaic monitor image. In the mosaic monitor mode, first, the user looks at the original image of the preliminary scan displayed on the display unit 84 of the operation panel 70, and determines a region of interest (for example, a hatched portion in FIG. 5) where color adjustment is best performed. Set. In response to this, the registered image memory circuit 1 stores only the image data I corresponding to the set value of the attention area in the next scan in the memory. Note that an upper limit is set for the size of the attention area in accordance with the storage capacity of the memory.

Next, the image tone setting circuit 2 prints the image data of various colors from the image data I read from the registered image memory circuit 1 and becomes the printing color data by the masking processing circuit 24 on the same paper. I '= kI (k = Ky, K
m, Kc). Here, Ky, Km, and Kc are color correction coefficients K for yellow, magenta, and cyan, respectively.
It is. FIG. 6 shows an example of the output format. In this example, cyan (c), magenta (m), yellow (y)
, Three kinds of color correction coefficients Ky = y _i , Km = m _i ,
Using Kc = c _i (i = 0, 1, 2), 3 × 3 × 3 = 2
Outputs seven types of images. Here, the color correction coefficients c ₁ , m ₁ , and y ₁ with “1” represent standard coefficients for color adjustment.
Color correction coefficients c ₀ , m ₀ , y _{0 with} “0” and “2”;
c ₂ , m ₂ and y ₂ are standard coefficients c ₁ , m ₁ and y ₁ , respectively.
Is multiplied by a predetermined factor smaller than 1 and a predetermined factor larger than 1.

The user selects an optimum color tone from the 27 types of output images shown in FIG. This ends the mosaic monitor mode. By the way, the mosaic monitor image GM
In order for the user to specify an image to be selected from among the above, for example, the function keys 78 to 81 may be operated in accordance with a message displayed on the display unit 84 of the operation panel 70. Alternatively, the image block of FIG. 6 may be displayed on the display unit 84, and the coefficients may be selected by designating the block coordinates using the function keys or numeric keys.

Next, the original is read again and an image is printed in the set color tone. There are various needs of users who use the mosaic monitor, and there are cases where the color adjustment needs to be largely changed or strictly changed. A color correction adjustment function of the mosaic monitor is provided to meet these needs. The color correction coefficients Ky, Km, and Kc can be changed in two ways: before performing the mosaic monitor and after viewing the printed mosaic monitor image. In the present embodiment, the color correction coefficients c _i ,
m _i , y _i (i = 0, 2) are standard color correction coefficients c ₁ ,
It is obtained by subtracting and adding a predetermined color correction adjustment value a to m ₁ and y ₁ . Therefore, the adjustment before performing the mosaic monitor is performed by changing the color correction adjustment value a. Color correction adjustment value a
Can be set by a numeric key 75 on the operation panel 70. With this setting, the color correction coefficient is changed as follows. _{y 0 ← y 1 - a y} 2 ← y 1 + a m 0 ← m 1 - a m 2 ← m 1 + a c 0 ← c 1 - If a c ₂ ← c ₁ + want significantly changed a color adjustment If it is desired to increase and decrease the value of a, the value of a may be set small.

The adjustment of the color correction coefficients Ky, Km and Kc after viewing the mosaic monitor image is also performed by changing the color correction adjustment value a. In this case, the color correction adjustment value a is changed using the density correction key 80 on the operation panel 70. When performing the mosaic monitor, the density is normally printed at the same density as the original, so that the density adjustment coefficient is set as a standard value (FIG. 13, S5).
2). Therefore, it is not necessary to perform density correction using the density correction key 80. Therefore, in the mosaic monitor mode, the density correction key 80 is used as a color correction key for color correction. Therefore, a selector 35 for switching between density correction and color correction is provided as shown in FIG.
When the mosaic monitor select signal is received from 5, the signal from the density correction key is sent to the CPU 25 as a color correction adjustment value signal. That is, when the density correction key 80 is pressed on the operation panel 70, the level is incremented by one step and displayed on the display section 84 as inverted characters. This level is made to correspond to nine levels of color correction adjustment values a as shown in FIG. Therefore, when the set key 76 is pressed, the CPU 25 sets the color correction adjustment value a corresponding to the level.
, Color correction coefficients y _i , m _i , and c _i (i = 0, 2) are set. Thus, the density correction key 80 is used as a color correction key.

When the level is 5, the color is a standard color. If you want to increase the one-step color change of the mosaic monitor image,
The color correction adjustment value a can be changed by selecting one of 6 to 9 and changing it to a smaller value by selecting 1 to 4. At this time,
As with the previous adjustment performing mosaic _{monitor, y 0 ← y 1 - a} y 2 ← y 1 + a m 0 ← m 1 - a m 2 ← m 1 + a c 0 ← c 1 - a c 2 ← c ₁ + a

After performing the color correction in this manner, the memory contents are read out again and the mosaic monitor image is printed. Then, a desired color adjustment is selected from the mosaic monitor image.
In the present embodiment, the mosaic monitor image is printed while changing the three colors C, M, and Y in three steps. However, when the user wants to perform color adjustment more densely, more steps (for example, five steps) are performed. It is also possible to print by changing to (stage). Although a detailed description is omitted, a read area setting signal and an image tone setting circuit 2 which the CPU 25 gives to the registered image memory circuit 1
The number of stages can be changed by controlling the color correction coefficient given to the image.

(C) Picture Tone Setting Circuit FIG. 9 is a circuit diagram of the picture tone setting circuit 2. The image tone setting circuit 2 is a circuit for performing color correction (color adjustment) of a mosaic monitor image provided at the next stage of the masking processing circuit 24. The masking processing circuit 24 converts the image signals of the three colors of R, G, and B for printing corresponding to the printing colors of Y (yellow), M (magenta), C (cyan), and K (black). The image signal is converted into an image signal (print signal), and the converted image signal is output to the image tone setting circuit 2. As is well known, a conversion formula for converting the original image signals R, G, B into print signals Y, M, C is expressed as follows.

(Equation 1) The conversion coefficients a _{00 to} a ₂₂ are preset to appropriate values by theory and experiment so that an image of a color as close as possible to the original image is printed.

The image tone color adjustment in the setting circuit 2, each printing signal Y obtained by the above calculation, M, with respect to _{C, Y 1 = Ky × Y} M 1 = Km × M C 1 = Kc × C To obtain the adjusted print signals Y ₁ , M ₁ , and C ₁ . Here, Ky, Km, and Kc are color correction coefficients for yellow, magenta, and cyan, respectively. Note that the black print signal K is output only for pixels that are printed in all three print colors of Y, M, and C. Also, no color adjustment is required.

In the mosaic monitor mode, as shown in FIG. 6, a different set of color correction coefficients is given to each block. That is, the read area specified by P ₀ (x ₀ , y ₀ ) and P ₁ (x ₁ , y ₁ ) is divided into blocks of three columns in the main scanning direction X and nine rows in the sub-scanning direction Y, Different combinations are set for each classification. In that case, the coefficient Ky of Y (yellow) is
It does not change in the sub-scanning direction Y, and in the main scanning direction X, y ₀ , y ₁ , y ₂
And the coefficient Km of M (magenta) does not change in the main scanning direction X but m ₀ , m ₁ ,
_{m 2, m 0, m 1} ... sequentially changed, coefficient Kc of C (cyan) is not changed in the main scanning direction, every third block in the sub-scanning direction
It changes to c ₀ , c ₁ , c ₂ . Therefore, the image tone setting circuit 2
In the mosaic monitor mode, a color correction coefficient is set for each block of the mosaic monitor image for each of the print signals Y, M, and C as described above, and an adjusted print signal is output.

In the image tone setting circuit 2, the multiplier 301
Performs an operation for obtaining the print signals Y ₁ , M ₁ , and C ₁ described above. Here, in order to set three coefficients in the main scanning direction in the mosaic monitor mode, three latches 3 are used.
02, 303, and 304, a latch circuit 305 is provided.
The coefficient output from the reference numeral 25 is set. These three coefficients are values corresponding to three blocks in the main scanning direction, respectively. Each time a variable-speed sub-scanning clock is input to the CPU 25 as an interrupt signal, an interrupt process (see FIG. 14) is performed. Each time the CPU 25 advances by one block in the sub-scanning direction, the CPU 25 outputs a latch signal to the image setting circuit 2. And latch the new 3 coefficients for the next block.
Latch at 2,303,304.

The reason why the latch circuit 305 including the three latches 302 to 304 is provided is that the coefficient changing cycle in the main scanning direction is short, and it is difficult to set the coefficient in real time by the CPU 25 in terms of speed. . In addition,
If it is desired to use n color correction coefficients, n latches may be provided in parallel. Registered image memory circuit 1 described above
, The overflow signal X in the main scanning direction generated at the time of reading of the image memory 401 is input to the first selection signal generation circuit 311, and the first selection signal generation circuit 311
Each time the overflow signal X is input (for each block), the selector 306 outputs a signal for selectively switching each of the latches 302 to 304 sequentially. In the mosaic monitor mode, the selector 312 sets the output of the first selection signal generation circuit 311 to S21
Tell 6 The selector 306 selectively sequentially sends the coefficients latched in the latch circuit 305 corresponding to the signal S21 to the multiplier 301 for each block.

On the other hand, the overflow signal Y in the sub-scanning direction generated when reading the image memory 401 in the registered image memory circuit 1 is input to the selector 313, and the selector 313 latches the signal in the mosaic monitor mode. Notify the circuit 305. by this,
Each time the overflow signal Y is output, the latch circuits 302 to 304 latch and update the set of color correction coefficients output from the CPU 25. Therefore, when a block changes in the sub-scanning direction, the set of color correction coefficients changes immediately. If the color correction coefficient is selected in the mosaic monitor mode, the selected coefficient is
It may be set to 2 and output to the multiplier 301. In the superimpose mode, the selector 312 selects the output of the second selection signal generation circuit 314 and can make the color tone different between the superimposed area and another area, but the description is omitted.

(D) Registered image memory circuit The registered image memory circuit 1 registers the registered image of the target area of the document in the mosaic monitor mode in the memory 401,
A circuit for reading and printing at an arbitrary designated position on a sheet for copying. FIG. 10 shows a registered image memory circuit 1.
FIG. Here, the memory 401 is a RAM for recording a registered image. The selector 421 selects the image data subjected to the shading correction and the 'white' data.
When reading and printing the mosaic monitor image, 'white' data is selected. The output signal of the selector 421 is
The data is sent to the memory 401 and the selector 446 via the state buffer 422. 3-state buffer 422
Is in a high impedance state only when the memory 401 is being read during printing of the mosaic monitor image (NOE = “1”). In other cases, when the mosaic monitor image is not printed in the mosaic monitor mode,
Output 'white' data. When registering an image in the mosaic monitor mode, image data is output.

When the registered image is a full-color image,
Color adjustment is often required. Therefore, selector 4
The 46 and the 3-state buffer 422 interpose a memory before the intermediate processing, and store the multi-value data in the memory. By reading the registered image data, the mosaic monitor image can be printed with various color adjustments. The writing area determination circuit 402 determines whether or not the writing area exists in the main scanning direction or the sub scanning direction based on the writing area setting signals in the main scanning direction (X) and the sub scanning direction (Y) set by the CPU 25. Is determined. Based on the result of the determination, the AND gate 407 stores the clock NCKA (hereinafter, the symbol of the negative logic signal is prefixed with N) in the memory 40 when it is in the write area.
1 to the NWE terminal 1 to enable writing to the memory 401.

Similarly, the read area determination circuit 408 determines whether
Main scanning direction (X) and sub-scanning direction (Y) set from U25
Is determined in the main scanning direction or the sub-scanning direction based on the readout area setting signal (the readout area is determined by the output format). Based on the result of the determination, the AND gate 405 outputs the NWE of the memory 401 via the inverter 423 when it is in the read area.
'0' is output to the terminal to make the memory 401 readable. Write and read addresses for the memory 401 are generated by a write address generation counter 403 and a read address generation counter 409, respectively, and output to an address terminal of the memory 401 via the selector 404. The selector 404 selects a write address or a read address depending on whether writing or reading is performed. Each of the write address and the read address is generated as a one-dimensional address using a multiplier based on the address in the X direction and the address in the Y direction. Note that the selector 446 and the AND
In the superimpose mode, when printing an original image, the gate 448 adds a “white” to the superimposed image portion.
Although provided for outputting data, detailed description is omitted. Except when the trimming signal is output in the superimpose mode, the selector 446 selects the output signal of the 3-state buffer 422 or the memory 401. Hereinafter, the registered image memory circuit 1 will be described in more detail.

In writing a registered image, when the user designates a region of interest, the CPU 25 determines how many lines (in the Y direction) this region is viewed from the front end of the image and further in the main scanning direction (X direction). The number of pixels within the range is calculated, that is, the coordinates (x ₀ , y ₀ ) of the upper left corner and the coordinates (x ₁ , y ₁ ) of the lower right corner of this area are obtained, and these coordinates are determined in the X direction and Y A write area setting signal for determining the write area in the direction is set in each of the X section 402a and the Y section 402b of the write area determination circuit 402. X and Y are respectively
Main scanning direction and sub scanning direction. Write area determination circuit 40
The X section 402a and the Y section 402b of the second section count the horizontal synchronization signal Hsync and the clock CKA when the image leading end signal is input, and compare whether the count value is within the write area setting range. If the main scanning direction is in a range as long as _{(x 0 ≦ x ≦ x 1} ) outputs NWEX = 'L', the sub-scanning direction is within a range _{(y 0 ≦ y ≦ y 1} ) NWEY =
'L' is output. Write address generation counter 403
Generates a write address when the write area determination circuit 402 determines that the area is a write area, and sends it to the address terminal of the memory 401 via the selector 404. That is, NWE is used in the X section 403a of the write address generation counter 403.
When X = 'L', the clock CKA is counted, and an address in the main scanning direction is generated. This address is cleared by the horizontal synchronization signal Hsync. Also, the Y section 403b of the write address generation counter 403 has NWEY =
When it is "L", the horizontal synchronization signal Hsync is counted and an address in the sub-scanning direction is generated. This address is C
It is cleared by the image leading edge signal generated by the PU 25.
The write address generation counter 403 includes a multiplier, and calculates a one-dimensional address from both addresses in the X and Y directions.

In this manner, the address is generated and the memory 40
When the image data is written in No. 1, the data holding signal is set to "L" and the write / read signal is set to "L".
As a result, the selector 404 selects the address signal from the write address generation counter 403 because the selection signal is sent via the AND gate 405 and transmits the address signal to the address terminal of the memory 401. Further, the inverter 406 and the AN
The clock NCKA is transmitted to the NWE terminal of the memory 401 via the D gate 407, and enables writing to the memory. Further, since the write / read signal is set to “L”, the 3-state buffer 422 becomes active via the AND gate 405 only when the original image can be written, and the image data of the memory 401 is stored in the memory 401. Notify to I / O terminal.

As a result, the memory 401 can store only the image of the area determined by the writing area determination circuit 402 to be within the range in both the main and sub scanning. When the writing is completed, the CPU 25 sets the data holding signal to “H”.
And prohibits writing through the AND gate 407,
The contents of the memory 401 are held. When reading the data stored in the memory 401, it is necessary to read the data so that the data is printed in a designated reading area. The circuit configuration required for reading is almost the same as that for writing. CPU25
Is a read area determining circuit 4 for determining a read area for a sheet.
The X part 408a and the Y part 408b of the X.08 respectively have x ₀ ≦
When x ≦ x ₁ and y ₀ ≦ y ≦ y ₁ , set values that can be determined to be within the range are given. x ₀ and y ₀ are the X and Y coordinates of the upper left corner of the read image area, and x ₁ and y ₁ are the X and Y coordinates of the lower right corner (see FIG. 6). When an image leading end signal is input during scanning, the readout area determination circuit 408 counts the horizontal synchronization signal Hsync and the clock CKA, and
A comparison is made as to whether or not the count value is within the readout area setting range. If the main scanning direction is within the range, NREX =
'L' is output and if the sub-scanning direction is within the range, NREY
= 'L' is output.

The read address generation counter 409 generates a read address when the read area determination circuit 408 determines that the area is a read area. Since the write / read signal is "H" at the time of reading, the read address generation counter 409 operates the selector 404. The address is sent to the address terminal of the memory 401 via the memory. That is, the X section 409a of the read address generation counter 409
When X = 'L', the clock CKA is counted, and an address in the main scanning direction is generated. This address is cleared by the horizontal synchronization signal Hsync. Further, the Y part 409b of the read address generation count 409 is NREY =
At the time of "L", the sub-scanning clock from the scaling sub-scanning clock generator 29 is counted, and an address in the sub-scanning direction is generated. Counting the sub-scanning clock instead of the horizontal synchronizing signal Hsync takes into account magnification.
This address is cleared by the image leading edge signal generated by the CPU 25. One-dimensional addresses are generated from the addresses in the main scanning direction and the sub-scanning direction.

Data read by accessing the memory 401 is transmitted to the subsequent stage. At this time, of course, in the read area, a count request is made even if the read address counter 409 exceeds the maximum size of the memory. In this case, the X section 409a and the Y section 409 of the read address counter are used.
b is an overflow signal X,
Y is output, and counting is started again from the initial value. The overflow signals X and Y are output to the image setting circuit 2 arranged at the subsequent stage. The overflow signal X,
Y is used when a plurality of images are arranged in the horizontal direction and printed with different color tones in the mosaic monitor mode.

In reading, since the write / read signal is at "H", the read area (NREX =
(“L”, NREY = “L”), the memory 401 is in an output enabled state via the AND gate 405 and the inverter 423, and the 3-state buffer 422 is in a high impedance state via the AND gate 405. The image data input side is separated from the memory 401. When the memory 401 is readable (NOE = “L”), the selector 446 sets the AND gate 448
The read data of the memory 401 is selected by a selection signal transmitted through the memory. In other cases, the data must be read so as to perform printing as in the format of FIG. 'White' data to select 'white'. At this time, the reading area discriminating circuits 408a and 408b include the original reading magnification and
Coordinates are set in consideration of the difference between the content of the memory 401 and the print magnification. It should be noted that the magnification-change sub-scanning clock is set to match the original reading magnification.

If it is desired to output a 3 × 9 image taking the example of FIG. 6 as an example, the method of reading out the memory is as follows.
When the contents of the same line are read out once and all the contents are read out in the sub-scanning direction, the main scanning direction is read out again from the beginning. When the output of the X section 408a and Y section 408b of the read area determination circuit for determining the read area for the paper is possible (NOE = 'L'), the address is read by the X section 409a and Y section 409b of the read address generation counter. Then, the memory 401 is accessed using the address, and the held image data is transmitted to the subsequent stage via the selector 446. Here, the CPU 25 controls the X section 40 of the readout area determination circuit.
8a, when x ₀ ≦ x ≦ x ₁ , Y section 408b includes y ₀
When a ≦ y ≦ y _1, previously given a set value that can be determined to be within the read area. At this time, the read address generation counter 409 sets the maximum size of one block (= (x ₁ −x ₀ ) / 3).
, An overflow signal X is output,
Start counting again from the initial value. Then, the contents of the same line are read. This is repeated three times. When advancing by (y ₁ −y ₀ ) / 9 in the sub-scanning direction, reading of three blocks in the horizontal direction is completed, and an overflow signal Y is output. Thus, three images are printed in the horizontal direction. By repeating this nine times in the sub-scanning direction, a mosaic monitor image of 3 × 9 blocks is read. In the image tone setting circuit 2, since different color correction coefficients are set for each block corresponding to the overflow signals X and Y (FIG. 1).
4), each image is printed with different color adjustments.

(E) Flow of Copying Machine Control in Mosaic Monitor Mode FIG. 11 shows a CPU 25 for controlling a digital color copying machine.
3 shows a main flow relating to the superimpose function of the copy operation control and the mosaic monitor mode. Operation panel 70
When the function key 78 or 79 is depressed to enter the superimpose mode or the mosaic monitor mode, the main flow is entered. If there is a request for image registration (YES in step S1, hereinafter "step" will be omitted), image registration processing is performed (S2, see FIG. 12). Image registration refers to registering the content of an image in a specified area. Selecting the normal mosaic monitor mode means that the image registration request (S1) and the mosaic monitor output request
(S3) Both are "YES". Selecting the superimpose mode means that the image registration request
Both (S1) and the superimpose mode output request (S5) are "YES". In the image registration process (S2),
An area desired by the user is set, and the contents of the area are registered in the memory. In the area setting, a document image is read, the read image is displayed on the display unit 84, and a desired area is set using the jog dials 82 and 83 and the set key 76.

If there is a mosaic monitor output request (YES in S3), mosaic monitor output processing (S4, see FIG. 13)
I do. That is, the registered contents are read out, subjected to various color corrections, and output as a mosaic monitor image. At this time, copying conditions such as the number of prints and magnification are reset to an initial state (all reset), and the density adjustment level is set to a standard value. When an image having a color balance desired by the user is selected from the output mosaic monitor images and a copy request is made (YES in S7), a copy operation is started.
(S8) When copying is performed until the copying is completed (S9), the entire image is obtained with the color balance. In the case of a superimpose output request (YES in S5), superimpose output setting is performed (S6). That is, after checking whether there is a registered image, the setting for reading from the memory is performed. Next, when a copy request is made (YES in S7), copying is performed (S8, S9), and the registered image is printed over the original image. If there is no image registration request, mosaic monitor output request, or superimpose output request (S1, S
3 and S5, both are NO), and normal copying is performed (S7 to S7).
S9). Note that the mosaic monitor, area setting in the superimpose mode, and the like are performed using the display unit 84.

FIG. 12 shows the flow of the image registration process (S2). When the set key 76 is pressed on the operation panel 70, the area setting value set on the display unit 84 at that time is input (S21). Further, other various input values are set (S22). Next, it is determined whether or not the color correction coefficients Ky, Km, Kc are changed (S23). When there is an input with the numeral key 75, it is determined that the color correction coefficient is changed. When a numerical value is input using the numeric key 75, the value is set as the color correction adjustment value a (S24). Then, the color correction coefficient is changed using the coefficient a (S25). That is, y ₀ ← y ₁ − ay ₂ ← y ₁ + am ₀ ← m ₁ − am ₂ ← m ₁ + ac ₀ ← c ₁ − ac ₂ ← c ₁ + a

Next, it is determined whether or not to start the image registration (S31). To start image registration, the coordinates of the vertices (upper left corner and lower right corner) of the registered image area are calculated from the input area setting value (S21), and the original image in that area is read (S32). The signal is subjected to shading correction (S33), and the correction value is written into the memory 401 (S3
4). Then, the image registration request is cleared (S35), and the process returns. When image registration is not started (N in S31)
O), immediately clear the image registration request (S35) and return.

FIG. 13 shows a mosaic monitor output process (S4).
The flow of is shown. First, all the setting values used for the mosaic monitor are reset (S51), and the density adjustment coefficient is set as a standard value (S52). That is, if the density adjustment coefficient has been changed before performing the mosaic monitor, the density adjustment coefficient is automatically returned to the original standard value. By always returning to the standard value in the mosaic monitor mode, it is possible to prevent errors in selection of color adjustment in the mosaic monitor mode. Next, the memory 40 of the attention area
1 is read out (S53), and the color correction coefficients y _i , m _i , and c _i are output to the image tone setting circuit 2 to perform color correction (S54), and print a mosaic monitor image (S55).

Next, it is determined whether or not the color correction coefficients y _i , m _i , c _i are changed (S61). When the density correction key 80 is pressed on the operation panel 70, the color correction coefficient is changed. When the set key 76 is pressed, the density correction key 8
A predetermined color correction adjustment value a is set according to the change of the color adjustment level due to 0 (S62). Then, the color correction coefficients y _i , m _i , and c _i are changed using the value a (S63). That is, y ₀ ← y ₁ − ay ₂ ← y ₁ + am ₀ ← m ₁ − am ₂ ← m ₁ + ac ₀ ← c ₁ − ac ₂ ← c ₁ + a

Next, when it is determined that the print start key 71 has been pressed (YES in S64), the flow returns to S53 to start printing the mosaic monitor image. At this time, the original image is not scanned, and printing is performed based on the image data in the memory 401 (S53 to S55). If printing is not to be performed (NO in S64), the process immediately proceeds to S71. Next, when an image (block) desired by the user is selected from the mosaic monitor images on the display unit 84 (S71), the color correction coefficients K _y , K _m , and K _c according to the selected image are set. Set (S7
2). When the print start key 71 is pressed to request a copy (S73), scanning of the document is started, and copy is started using the set color correction coefficients y _i , m _i , and c _i (S73).
74). Until the copying is completed (S75), copying is performed, and the process returns.

FIG. 14 is a flow chart for setting coefficients for color adjustment in printing a mosaic monitor image. This process is interrupted by the CPU 25 every time the horizontal synchronization signal Hsync is generated, and is executed as an interrupt routine. Among them, the counter C
t ₁ counts the distance in the sub-scanning direction from the leading end of the print sheet P (image top), to detect the end beginning printing of the mosaic monitor image GM and printing. Counter Ct ₂ counts the distance in the sub-scanning direction, detects a change in the block of the mosaic monitor image. T represents the distance in the sub-scanning direction from the leading edge of the image to the printing position of the mosaic monitor image, and l
Represents the distance of one block in the sub-scanning direction (see FIG. 6).

First, the state is determined in S300, and the process branches depending on the value "0" to "4". When the state is "0", whether the image tip (leading edge of the paper P) is determined (S301), when the image leading edge has passed the counter Ct ₁ initializes (S302), the state "1" To (
S303). When the state is “1”, the counter Ct ₁
There Wait for the T (S311), i.e. waits for reaching the position of the coordinate y ₀ is the tip of the mosaic monitor image GM, then the color of the developing device of the toner to be used, state "2", "3 ”, Or“ 4 ”. That is, when it is Y (yellow) (YES in S312), the state is set to “2” (S313). When M (magenta) (S
YES in 321), the counter Ct ₂ initializes (S32
2) The variable i is set to “0” (S323), and the state is set to “3” (S324). When C (cyan) (NO in S321)
The counter Ct ₂ initializes (S331), the variable j is "0" (S332), the state is "4" (S333).

When the state is "2", a latch signal is output to the image tone setting circuit 2 and y ₀ , y ₁ , y ₂ are latched as coefficients 1 to 3 set in the latches 302, 303, 304, respectively.
(S341), waits counter Ct ₁ is to become (T + 9l), that is, the rear end of the mosaic monitor image GM coordinates
Wait for reaching the position of y ₁ (S342), the state is set to "0" (S343). When the state is "3", by substituting m _i in the coefficient latch 302 to 304 1 to 3 (S35
1), the counter Ct ₂ is Wait for the l, i.e. waits for one block of the mosaic monitor ends (S35
2), the counter Ct ₂ initializes (S353), increments by one the variable i (S354). Next, it waits until the rear end of the mosaic monitor image is reached (S355), and sets the state to "0" (S356). That is, here, the coefficients 1 to 3
_Are set to the same value m _{i, and} each time the mosaic monitor image changes by one block in the sub-scanning direction, the coefficient 1
３3 is changed to a new value mi _{+ 1} .

When the state is "4", the latches 302 to 302
Substituting c _j the coefficients 1 to 3 304 (S361), waits counter Ct ₂ is to become (3l), i.e. waits for three blocks of the mosaic monitor ends (S362), the initial counter Ct ₂ (S363), and increments the variable j by one (S364). Next, it waits until the rear end of the mosaic monitor image is reached (S365), and sets the state to "0" (S366). That is, here, the latches 302 to 30
The same value c _j is set for the coefficients 1 to 3 of 4 and the coefficients 1 to 3 are changed to new c _{j + 1} every time the mosaic monitor image changes by 3 blocks in the sub-scanning direction. Upon completion of the processing in each state, the counters Ct ₁ and Ct ₂ are incremented (S371). Through the above processing, various coefficients are set for each print color for each block, and color adjustment is performed.

[0051]

In the color image processing in the mosaic monitor mode, since the density is always set to the standard value, the possibility that the operator makes a mistake in selecting the color adjustment is reduced.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of a digital color copying machine.

FIG. 2 is a block diagram of a signal processing unit.

FIG. 3 is a timing chart of image data processing.

FIG. 4 is a plan view of an operation panel.

FIG. 5 is a diagram showing a region of interest setting.

FIG. 6 is a diagram of an output format of a Zyke monitor image.

FIG. 7 is a diagram of a selector.

FIG. 8 is a diagram showing levels of density correction and color correction.

FIG. 9 is a circuit diagram of an image tone setting circuit.

FIG. 10 is a circuit diagram of a registered image memory circuit.

FIG. 11 is a main flowchart relating to a mosaic monitor mode of the digital color copying machine.

FIG. 12 is a flowchart of an image registration process.

FIG. 13 is a flowchart of a mosaic monitor output setting.

FIG. 14 is a flowchart of an interrupt process.

[Explanation of symbols]

1 ... registered image memory circuit, 2 ... image tone setting circuit, 20 ...
Signal processing unit, 25: CPU, 70: Operation panel,
78: mosaic monitor selection key, 79: density correction key (color correction key), 84: display unit, 401: memory.

Continuation of the front page (56) References JP-A-63-94256 (JP, A) JP-A-61-121664 (JP, A) JP-A-1-127607 (JP, A) JP-A-1-255542 (JP) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H04N 1/40-1/409 H04N 1/46 H04N 1/60

Claims (4)

(57) [Claims] An image memory for storing input image data; a color correction means for performing a color correction operation on image data read from the image memory; and a means for inputting a density signal corresponding to a set density level. Means for setting an output density level at the time of image output based on the density signal; and a mosaic monitor mode for performing different color correction operations on specific image data and outputting a plurality of images adjacently. An input unit for inputting a mosaic monitor signal, and when the mosaic monitor signal is input, the output density level is set to a standard value regardless of the input density signal, and the image data read from the image memory is different from each other. Control means for performing a color correction operation and outputting a plurality of image data. 2. A color image forming apparatus comprising the color image processing circuit according to claim 1. 3. The color image forming apparatus according to claim 2, further comprising: a printer unit; and print control means for controlling a print density of the printer unit based on the set output density level. apparatus. 4. A color image processing method in a mosaic monitor mode for performing different color correction operations on specific image data stored in an image memory and outputting a plurality of images adjacent to each other, comprising: A density signal corresponding to the level is input, an output density level at the time of image output is set based on the density signal, a mosaic monitor signal indicating a mosaic monitor mode is input, and an input is performed with the input of the mosaic monitor signal. Output density level to a standard value regardless of the density signal
Read the same image data from the image memory multiple times,
A color image processing method wherein different color correction operations are performed and output.