JPH1120207A - Apparatus and method for correcting print data, and software-recording medium having print data correction program recorded therein - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correctly reproduce colors irrespective of instrumental errors of a printing head, etc., by correcting print data based on a predetermined correction amount compensating for a bias of a usage of a recording material set for every element, and reducing the correction amount more when color elements are combined to carry out mixed color recording than at the time of monochromatic recording. SOLUTION: A correcting means 30a1 corrects print data on the basis of a predetermined correction amount compensating for a bias of a usage of a recording material set for every element color. A printing apparatus adheres the recording material of each element color in matrix to a recording medium, thereby printing and outputting color images in a plurality of element colors. A correction-reducing means 30a2 reduces the correction amount more when the element colors are combined to realize recording in mixed colors than at the time of monochromatic recording. A print data-correcting apparatus 30a corrects in a predetermined manner print data when the print data are generated. The correcting means 30a1 preliminarily holds the correction amount for correcting an instrumental error for every element color and corrects the print data based on a reduction instruction from the correction amount- reducing means 30a2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a print data correction device, a print data correction method, and a software recording medium on which a print data correction program is recorded.

[0002]

2. Description of the Related Art In recent years, the definition of a color ink jet printer has been advanced, and the color ink jet printer has been called a so-called photographic image quality. In such an ink jet printer, a predetermined color dot is attached to a desired position by discharging a predetermined color ink in a granular form, and an image is expressed in a dot matrix form. In this case, a color image is reproduced using three color inks of cyan (C), magenta (M) and yellow (Y) or four color inks obtained by adding black (K) thereto.

[0003] In order to be referred to as photographic image quality, it is important to reduce the size of dots, but color reproducibility is also extremely important. In spite of the fact that colors are represented by red, green and blue (RGB) multi-gradation data inside the computer, the printer can only support CMYK two-gradation data. Have been done. In other words, it is realized by CMYK two-gradation display while maintaining the color represented by RGB multi-gradation. Of course,
Here, it is assumed that each dot is colored at a prescribed density.

However, although the print data is output while maintaining the color reproducibility, the weight of the color ink particles varies depending on the machine difference between the print heads. It may not be said that the color is developed at the density.

[0005]

In the above-described conventional printing apparatus, if the amount of ink droplets to be ejected is different due to the difference in the body of the print head, it cannot be said that each dot is colored at the original density. As a result, there is a problem that color reproducibility may deteriorate.

Therefore, in the case of the present applicant, the print data is corrected in advance to compensate for machine differences, and printing is performed based on the corrected print data to improve color reproducibility. Such modifications use a modification table. To create this correction table, first
The patches are printed over all gradations by the reference print head that discharges the color ink particles of the reference weight, and the patches are printed over all gradations by the print head having the machine difference. Then, each patch is compared to obtain a combination of patches having no error, and a list of the combinations is used as a correction table.

Since it is necessary to compare patches for comparison, it is impossible to compare patches for all reproducible colors. Therefore, when a correction table was created for each elemental color, when printing a single color, substantially the same color development as in the case of the reference head could be obtained, but when color mixing was performed, a shift occurred again.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has a print data correction apparatus, a print data correction method, and a print data correction method capable of reproducing colors more accurately irrespective of machine differences such as print heads. It is an object of the present invention to provide a software recording medium on which a print data correction program is recorded.

[0009]

According to a first aspect of the present invention, there is provided a recording material for each element color in order to print out a color image in a plurality of element colors based on print data. A print data correction device that corrects the print data in order to compensate for a color change based on a bias in the amount of use of the recording material for a printing device attached to a recording medium in a dot matrix form. Correction means for correcting the print data based on a predetermined correction amount for compensating for a bias in the set use amount of the recording material, and correction by the correction means as compared with a single color when mixing colors realized by combining respective element colors. And a correction amount reducing means for reducing the amount.

[0010] In the invention according to claim 1 configured as described above, the correction means corrects the print data based on a predetermined correction amount for compensating for the deviation of the usage amount of the recording material set for each element color. Based on the corrected print data, the printing apparatus attaches a recording material for each element color to a recording medium in a dot matrix form, and prints out a color image with a plurality of element colors. In this case, the correction amount reducing means reduces the correction amount at the time of color mixture realized by combining the element colors when the correction means corrects the print data, as compared with the case of the single color.

An experimental result has been obtained that when the correction amount for a single color is applied to a mixed color, the correction amount set for a single color is too strong. This can be due to various factors, but it is reasonable to think that the amount of correction for each elemental color is too strong due to color mixing. The corrected amount is not used as it is in the case of mixed colors, and the reproducibility of mixed colors is improved.

Here, the correction unit has a correction amount in a single color for at least each element color, and corrects the print data by reducing the correction amount based on an instruction of the correction amount reduction unit. The correction may be made individually for each print data, or if there is a conversion table to be referred to by the print data, the conversion table is collectively corrected, and the conversion table is individually corrected. If referred to, the conversion and the modification may be performed.

Further, the correction amount reducing means only needs to reduce the correction amount by the correction means at the time of color mixing as compared with the case of single color, and the reduction amount is not uniform. However, as an example, the invention according to claim 2 is the print data correction apparatus according to claim 1, wherein the correction amount reducing unit further reduces the correction amount as the number of colors to be mixed increases. is there.

In the invention according to claim 2 configured as described above, the correction amount reducing unit reduces the correction amount as the number of colors to be mixed increases.

It is considered that the use of the setting of the single color at the time of the color mixture causes a shift, and the correction amount at the time of the single color is considered to be too strong. If this concept is extended, it is preferable to reduce the correction amount as the number of colors to be mixed increases. Becomes

The tendency in reducing the correction amount is as described above, but in reality, there are single colors, mixed colors, and the number of colors is various. Therefore, adjustment is required to determine the correction amount. As a preferred example in such a case, the invention according to claim 3 is the print data correction apparatus according to any one of claims 1 and 2, wherein the correction amount reducing unit determines the correction amount according to the number of colors to be mixed. Reduction amount storage means for storing the optimum reduction amount, and reduction amount weighting addition means for summing up the number of colors to be mixed for each pixel and adding the reduction amount with a weight corresponding to the number of pixels. .

According to the third aspect of the present invention, the reduction amount storage means stores an optimum reduction amount in accordance with the number of colors to be mixed, and the reduction amount weighting and adding means stores the color mixture of each pixel. The number of colors to be processed is totalized, and the reduction amount is added by weighting corresponding to the number of pixels.

Therefore, the optimum amount of reduction is added for each number of colors to be mixed by weighting according to the ratio of the number of pixels, and the amount of reduction is harmonized as a whole printed matter.

The method of reducing and applying the correction amount set for each element color at the time of color mixing in this manner does not necessarily have to be a substantial device. For example, the invention according to claim 4 In order to print out a color image with a plurality of element colors based on print data, a printing apparatus that attaches a recording material for each element color to a recording medium in a dot matrix form is based on a bias in the usage of the recording material. A print data correction method for correcting the print data to compensate for a color change, wherein a predetermined correction amount for compensating for a bias in the usage amount of the recording material is set for each element color, and The configuration is such that the print data is corrected by reducing the amount of correction at the time of color mixture realized by combining colors as compared with the case of single color.

In other words, there is no difference in that the method is not necessarily limited to the operation of correcting with a substantial device, but is also effective as a method.

Incidentally, as described above, a print data correction apparatus for correcting print data may exist alone or may be used in a state of being incorporated in a certain device. Is included. Further, it can be appropriately changed, for example, by hardware or software.

In the case of software for correcting colors as an embodiment of the idea of the present invention, the software naturally exists on a software recording medium on which such software is recorded.
I have to say that it is used.

As one example, the invention according to claim 5 is to attach a recording material for each element color in a dot matrix form to a recording medium in order to print out a color image in a plurality of element colors based on print data. For a printing device, a software recording medium that records a print data correction program that corrects the print data to compensate for a color change based on a bias in the amount of the recording material used by the computer,
A predetermined correction amount for compensating for the deviation of the usage amount of the recording material is set for each element color, and the printing is performed by reducing the correction amount when mixing colors realized by combining the element colors as compared with a single color. It is configured to correct data.

Of course, the software recording medium may be a magnetic recording medium, a magneto-optical recording medium, or any software recording medium to be developed in the future. Also, the duplication stages of the primary duplicated product, the secondary duplicated product, and the like are equivalent without any question. In addition, the present invention is still used even when the supply method is performed using a communication line, and the same applies to a case where the information is written on a semiconductor chip.

Further, even if a part is implemented by software and a part is implemented by hardware, there is no difference in the concept of the invention, and it is necessary to store a part on a software recording medium. May be in a form that is read as appropriate in accordance with.

[0026]

As described above, according to the present invention, there is no difficulty in obtaining the correction amount of the mixed color in the sense that the correction amount is set for each element color, and the correction amount is weakened at the time of the mixed color. As a result, it is possible to provide a print data correction apparatus capable of substantially eliminating color misregistration due to machine differences and improving color reproducibility.

According to the second aspect of the present invention, the correction amount is reduced as the number of mixed colors increases, whereby
When the number of colors is increased, the correction amount of each color alone is weakened, and good color reproducibility can be realized.

Further, according to the third aspect of the invention,
Since the number of pixels for each number of mixed colors is totaled and the optimum reduction amount is weighted and added to each pixel, a harmonious reduction amount can be obtained.

Further, according to the invention of claim 4,
Similarly, it is possible to provide a print data correction method capable of improving color reproducibility when mixing colors.

Further, according to the invention of claim 5,
Similarly, it is possible to provide a software recording medium on which a print data correction program capable of improving color reproducibility when mixing colors is recorded.

[0031]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a print data correcting apparatus according to an embodiment of the present invention in a claim correspondence diagram. FIG. 2 is a block diagram showing an example of a hardware configuration of a printing system to which the print data correcting apparatus is applied. Is shown.

This printing system can be roughly classified into an image input device 10, an image processing device 20, and a printing device 30. The image input device 10 corresponds to a scanner 11, a digital still camera 12, or a video camera 14, and the image processing device 20 includes a computer 21, a hard disk 22, a keyboard 23, and a CD-R.
The OM drive 24, the floppy disk drive 25, the modem 26, the display 27, and the like correspond thereto, and a specific example of the printing device 30 corresponds to the printer 31 and the like. The modem 26 is connected to a public communication line, is connected to an external network via the public communication line, and can download and install software and data.

Here, the scanner 11 and the digital still camera 12 as the image input device 10 output image data of 256 gradations of RGB (green, blue and red) as image data, and the printer 31 as the printing device 30 The image data of two gradations of CMYK (cyan, magenta, yellow, black) is required as input. Therefore, in the computer 21 as the image processing device 20, the image data of 256 gradations is input, predetermined image processing and printing processing are performed, and the image data is output as image data of two gradations. In the computer 21, an operating system 21a is operating, and a printer driver 21b and a display driver 21b corresponding to the printer 31 and the display 27 are provided.
c is installed and the application 21
The execution of the processing is controlled by the operating system 21a, and the display d displays on the display 27 in cooperation with the display driver 21c, and executes the printing processing in cooperation with the printer driver 21b as necessary.

In the present embodiment, in the process of generating print data in such a printing system, the print data correction device 30a inputs the generated print data, corrects the data, and outputs it. in this case,
The correction unit 30a1 previously holds a correction amount for correcting a machine difference for each element color as described later, and reduces the correction amount according to a reduction instruction from the correction amount reduction unit 30a2. Fix it. Hereinafter, this step will be described in detail.

First, the printer 31 for performing printing based on the corrected print data will be described. FIG. 3 shows a schematic configuration of the printer 31. The print head 31a includes three print head units, and the print head 31a includes three print head units.
a printhead controller 31b for controlling the printhead a, a printhead girder moving motor 31c for moving the printhead 31a in the column direction, a paper feed motor 31d for feeding the print paper in the row direction, these printhead controller 31b and the printhead A dot printing mechanism including a printer controller 31e, which is an interface between the digit moving motor 31c and the paper feed motor 31d, connects to an external device, and can print an image according to print data.

FIG. 4 shows a more specific configuration of the print head 31a, and FIG. 5 shows an operation at the time of ink ejection. The print head 31a is formed with a fine conduit 31a3 extending from the color ink tank 31a1 to the nozzle 31a2, and an ink chamber 31a is provided at the end of the conduit 31a3.
4 are formed. The wall surface of the ink chamber 31a4 is formed of a flexible material, and a piezo element 31a5, which is an electrostrictive element, is provided on the wall surface. The piezo element 31a5 has a crystal structure that is distorted by applying a voltage, and performs high-speed electrical-mechanical energy conversion.
The wall of 1a4 is pushed to reduce the volume of the ink chamber 31a4. Then, a predetermined amount of color ink particles is vigorously ejected from the nozzle 31a2 communicating with the ink chamber 31a4. This pump structure is called a micro pump mechanism.

It should be noted that two independent rows of nozzles 31a2 are formed in one print head unit, and color ink is independently supplied to the nozzles 31a2 in each row. Therefore, each of the three print head units is provided with two rows of nozzles, and it is possible to use six color inks by maximizing the use. In the example shown in FIG. 3, two rows in the left print head unit are used for black ink, only one row in the middle print head unit is used for cyan ink, and The left and right two rows are used for magenta ink and yellow ink, respectively.

As described above, the present embodiment is applied to the ink jet printer 31 employing the micropump mechanism. In the printer 31 having the dot attachment mechanism of the ink jet system,
Printing is performed by ejecting one ink particle for one dot from the print head 31a described above. However,
The size of one dot added in this manner is not always constant, and there is a machine difference in the print head 31a. In the case where the print density does not change due to so-called overprinting, the size of the dot affects the print density. Therefore, when the size of the dot has a machine difference, the print density varies, and in the color, the color balance and lightness vary, and in the monochrome, the gray density varies.

In this embodiment, the ink jet printer 31 employing the micropump mechanism has been described. However, any printer having a dot attachment mechanism may be used as long as there is a difference in the size of dots. Applicable.

For example, as shown in FIG.
A heater 31a8 is provided on the wall surface of the nearby conduit 31a7, and a bubble jet type pump mechanism that heats the heater 31a8 to generate bubbles and discharges color ink at the pressure is also in practical use. Even in this case, it is undeniable that a machine difference occurs due to the capability of the heater 31a8, the opening shape of the nozzle 31a6, and the like.

FIG. 7 shows a schematic structure of a so-called electrophotographic printer 33 as another mechanism. A charging device 33b, an exposure device 33c, and a developing device 33
d and the transfer device 33e are arranged. After the charging device 33b uniformly charges the peripheral surface of the rotating drum 33a, the exposure device 33c removes the charge of the image portion.
At 3d, the toner is attached to the uncharged portion, and the toner is transferred onto paper as a recording medium by the transfer device 33e. Thereafter, the toner is passed between the heater 33f and the roller 33g to melt the toner and fix it on paper.

Even in the case of such an electrophotographic printer 33, the amount of toner adhered to the charging device 33b, the exposure device 33c, or the rotating drum 33a itself varies. Therefore, a problem similar to that of the inkjet printer 31 occurs.

In this embodiment, the image input device 10
Although the computer system is incorporated between the printer and the printing apparatus 30 to perform the printing process, such a computer system is not always required. For example, as shown in FIG. 8, in a printer 32 that inputs and prints image data without going through a computer system, a scanner 11b or a digital still camera 12 is used.
Alternatively, it is possible to input image data as print data input via the modem 26b or the like, and to make corrections to eliminate machine differences.

Next, the correcting means 30a1 will be described. FIG. 9 illustrates the flow of image data, in which the image input device 10 displays RGB data as pixels in a dot matrix.
Image data of multiple gradations (256 gradations)
0, the image processing apparatus 20 performs predetermined image processing, and outputs to the printing apparatus 30 as CMYK two-tone image data (binary data). Image processing device 20
Inside, color conversion processing from the RGB color space to the CMYK color space is performed, and in this processing, RGB 256-gradation image data is converted into CMYK 256-gradation image data. Thereafter, in consideration of the fact that the data that can be input to the printing apparatus 30 has two gradations, halftone processing for converting the image data of 256 gradations into image data of two gradations is executed. The image data is converted into print data by the printing
However, since the data is substantially the same in the previous process, it can be called print data in a broad sense. The above-described print data correction apparatus 30a can also perform correction processing on print data at any stage in principle. In the present embodiment, the CMYK 256-tone image is simultaneously processed with the color conversion processing. It shall be performed on data.

FIG. 10 shows a procedure for rewriting a color conversion table for performing a correction process as a color conversion process. Here, the contents will be described according to the procedure.

First, in step S100, a correction lookup table for a primary color (single color) is created. Here, a procedure for creating the correction lookup table will be described.
As described above, first, the patches are printed over all gradations by the reference print head 31a that discharges the reference weight color ink particles. In the present embodiment, since there are 256 gradations, the printed patch has a grid shape of 16 rows and 16 columns as shown in FIG. Next, the print head 31a having a machine difference
However, similarly, the patches are printed over all gradations. In the print head 31a having a machine difference, since the weight of the ejected ink particles is shifted, the print density is shifted, and the reference print head 31a is shifted.
It does not match the patch printed over all gradations in a.

Therefore, as shown in FIG. 12, each patch printed by the reference print head 31a and each patch printed by the print head 31a having a machine difference are individually compared, and the gradation of the matching patch is compared. . FIG. 3 shows a combination of patches printed when predetermined tone data is input and having the same print density. Therefore, this combination constitutes a correction lookup table as it is. In this embodiment, since three print heads 31a are provided, a correction lookup table is created for each print head 31a. It should be noted that such a correction look-up table includes the above-described correction amount, and in this sense, can be said to be a correction amount for each element color.

By using the correction look-up table created for each print head 31a in this manner, it is thought that correction can be similarly performed for colors other than the primary color.
In reality, when a color mixture state such as a secondary color or a tertiary color occurs, a shift appears.

For this reason, in step S110, a secondary color patch is printed by reducing the correction amount in the correction lookup table. Here, the adjustment of the reduction amount is represented by multiplying a correction amount by a predetermined coefficient, and the coefficient is set to “0.
FIG. 1 shows a correction lookup table in the case of “1” increments.
It is shown in FIG. In the low gradation area and the high gradation area, the change is small and the change is difficult to see. However, when looking at the vicinity of the gradation “180” where the correction amount is the maximum, when the coefficient is “1.0”, the correction amount is “ It can be seen that the correction amount is reduced by approximately "2" gradation data by reducing the coefficient in "0.1" increments in the case where there is a difference of "20" gradation data. Of course, in the case of secondary colors, each print head 3
Use the individual correction look-up table in 1a multiplied by the same coefficient. In this case, the step size of the coefficient is not necessarily required to be “0.1”.

In step 120, the patch of the reference print head 31a printed in the secondary color in this way and the patch of the print head 31a having a machine difference in which the coefficient α2 is changed are respectively measured, and as a whole, The coefficient α2 that reduces the error is determined. According to the experimental results, the coefficient α2
Was most preferably "0.8".

Next, the coefficient α3 for the tertiary color is determined in the same manner. That is, in step S130, a tertiary color patch is printed by changing the coefficient α3, and step S14 is performed.
At 0, the optimum coefficient α3 is determined in comparison with the patch at the reference print head 31a. It was confirmed that the optimum coefficient α3 for the tertiary color was about “0.6”.

However, as described above, while there is an optimum coefficient for each of the primary colors to the tertiary colors, the print data includes various colors from the primary colors to the tertiary colors. Therefore,
Coefficients must be adjusted depending on which dimension of color reproducibility is important. In step S150, such an aiming color is determined, and a coefficient to be adopted is determined.

Here, the aiming color is determined, and the coefficient is determined based on the aiming color. However, the actual primary color, the secondary color, and the tertiary color are summed up to determine the coefficient. Is also good. FIG. 14 shows the result of counting the number of pixels of the primary color to the tertiary color based on all the pixels of the print data. The coefficients are weighted based on the result of the aggregation. In the example shown in the figure, the number of pixels of the primary color is s1, and the number of pixels of the secondary color is s.
Since the number of pixels of the two and tertiary colors is s3, the coefficients are weighted and added at a ratio to the total number of pixels (S = s1 + s2 + s3).

That is, the coefficient α0 which satisfies α0 = 1.0 × (s1 / S) + α2 × (s2 / S) + α3 × (s3 / S) (1) is used. On the other hand, when a component of one element color is mixed with a component of another element color at all, the number of primary colors and secondary colors is considerably large if it is determined that the color is necessarily a secondary color or a tertiary color. It will be less. However, in such a case, even if the correction is applied more strongly, the original component is small, so that the adverse effect is small. Therefore, it is also effective to determine that the color is a secondary color or a tertiary color only in a mixed color state where other element colors cannot be ignored.

FIG. 15 shows, as an example, a totaling result in the case where the judgment is made based on the component ratio for each element color, and the element color of the component value of 20% or less of the maximum component value is ignored. This is the case. As a result, the number of pixels of the primary color and the secondary color increases, and this also has an effect when obtaining the coefficient α0.

As described above, when the pixels are totaled on the basis of the print data and the result of the totalization is reflected, the optimum coefficients are obtained for the primary color, the secondary color, and the tertiary color. Hardware and software for storing the reduction amount storage means, and a process of totalizing and weighting and adding the number of pixels for each of the primary color, the secondary color, and the tertiary color from the actual print data is a reduction amount weighting addition means. Will be constituted.

For color correction, this correction look-up table may be referred to in CMYK print data.
Since the color conversion table is also referred to when performing color conversion from CMYK to CMYK, the color conversion table is rewritten, so that the correction operation is completed by referring to the table once. Therefore, in step S160, the correction lookup table of the determined coefficient is written in the color conversion table.
Of course, in this way, the coefficient is determined in correspondence with the aiming color, and the correction amount obtained by multiplying the coefficient is written in the color conversion table.
a2.

The above-described procedure is executed when the printer driver 21b is started by the computer 21, and the operation of the present embodiment having the above configuration will be described below with reference to the flowchart of the printer driver 21b shown in FIG. Will be described.

Assuming that the image data read by the scanner 11 is to be printed by the printer 31, first, the application 21 d is activated in the computer 21 while the operating system 21 a is running.
The scanner 11 starts reading. When the read image data is captured by the application 21d via the operating system 21a, predetermined image processing is performed, and print processing is selected.

When the printing process is selected, the operating system 21a activates the printer driver 21b. When the printer driver 21b is first activated, there is no primary color correction look-up table.
After the determination of 00, a single-color patch is printed in step S205. On the other hand, patches printed by the reference print head 31a are separately prepared, and compared with patches printed by the print head 31a provided for each printer 31,
In step S210, a value for which correspondence has been obtained is input.

In step S215, a secondary color patch is printed using the result. At this time, several patches are printed by changing the coefficient, and the coefficient α2 for the patch which is considered to be optimal is determined in step S220. Similarly, in step S225, a tertiary color patch is printed, and in step S230, the coefficient α
3 is determined. As the coefficient α2 and the coefficient α3, the coefficient of the one considered to be optimal is input. Once the above processing is performed, it is effective as long as the print head 31a does not change.

However, these steps S215 to S23
For the process of 0, it is assumed that the coefficients α2 and α3 need to be obtained. The coefficients α2 and α3 were experimentally determined to be “0.8” and “0.6”, respectively.
Have been found to be suitable, and using these values as defaults will give sufficiently effective results. Therefore, at least steps S205 and S21
If a single color patch is printed at 0 and only a predetermined corresponding value can be input, the processing of steps S215 to S230 may be omitted.

At the time of the first startup, the above-described printing and input are performed, the aiming color is determined in the next step S235, the corresponding coefficient is determined, and in the step S240, the process of writing in the color conversion table is performed.

However, the process here must be executed when it is desired to change the aiming color, and even if it is determined in step S200 that it is not necessary to create a primary color correction look-up table, the process proceeds to step S245. It is inquired whether or not it is necessary to change the aiming color, and if necessary, the processing of steps S235 and S240 is executed.

Thereafter, the RGB print data created by the application 21d is converted to CMY in step S250.
The color is converted into K print data. Needless to say, a color conversion table in which a predetermined correction amount is written in step S240 is used for the color conversion at this time, and necessary corrections are added simultaneously with the color conversion.

When the color conversion is completed, the print data is 2
Since the tone remains at 56, the print data is converted into print data of two tones that can be input by the printer 31 and output to the printer 31 in step S255. When the printer 31 inputs such print data, the amount of reduction of the correction look-up table is an optimum value in the vicinity of the aiming color, and as in the case of printing with the reference print head 31a, clear printing without color shift is performed. It becomes possible.

As described above, when the recording material such as the color ink forming the dots fluctuates due to the machine difference as in the ink jet printer 31, it is impossible to set the correction amount of the color misregistration for each color. However, at least the correction amount for a single color is determined, and if the aiming color is determined, the correction amount of the single color is reduced and applied with the optimal reduction amount, so that it is easily suitable for the secondary color and the tertiary color. Becomes possible.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to a claim of a print data correcting apparatus of the present invention.

FIG. 2 is a block diagram illustrating a specific hardware configuration example of a printing system to which the print data correction device is applied.

FIG. 3 is a schematic block diagram of a printer.

FIG. 4 is a more detailed schematic explanatory view of a print head unit in the printer.

FIG. 5 is a schematic explanatory view showing a situation where color ink is ejected by the print head unit.

FIG. 6 is a schematic explanatory view showing a situation in which color ink is ejected by a print head of a bubble jet system.

FIG. 7 is a schematic explanatory view of an electrophotographic printer.

FIG. 8 is a schematic block diagram showing another application example of the print data correction device of the present invention.

FIG. 9 is a block diagram illustrating a specific procedure of a printing process.

FIG. 10 is a flowchart illustrating a procedure for rewriting a color conversion table.

FIG. 11 is a diagram illustrating patches to be printed.

FIG. 12 is a diagram illustrating a comparison state of a patch by a reference print head and a patch by a print head having a machine difference.

FIG. 13 is a diagram showing a correction lookup table in which coefficients are changed.

FIG. 14 is a diagram illustrating a histogram when a coefficient is determined according to a pixel distribution ratio.

FIG. 15 is a diagram illustrating a histogram corresponding to the pixel distribution ratio, in which a threshold value is used at the time of aggregation.

FIG. 16 is a flowchart of a printer driver.

[Explanation of symbols]

 Reference Signs List 10 image input device 20 image processing device 21 computer 23 keyboard 30 printing device 31-33 printer

Claims (5)

[Claims] 1. A printing apparatus which prints a color image in a plurality of element colors based on print data and attaches the recording material for each element color to a recording medium in a dot matrix form. A print data correction device for correcting the print data to compensate for a color change based on a deviation in the amount, based on a predetermined correction amount for compensating for a deviation in the usage amount of the recording material set for each element color. And a correction amount reducing unit that reduces the correction amount by the correction unit compared with a single color when mixing colors realized by combining respective element colors. Correction device. 2. The print data correcting apparatus according to claim 1, wherein the correction amount reducing unit further reduces the correction amount as the number of mixed colors increases. 3. The print data correction device according to claim 1, wherein the correction amount reduction unit stores an optimal reduction amount according to the number of colors to be mixed. And a reduction amount weighting and adding means for totalizing the number of colors to be mixed of each pixel and adding the reduction amount by weighting corresponding to the number of pixels. 4. Use of a recording material for a printing apparatus that attaches a recording material for each element color to a recording medium in a dot matrix in order to print out a color image in a plurality of element colors based on print data. A print data correction method for correcting the print data to compensate for a color change based on an amount deviation, wherein a predetermined correction amount is set for each element color to compensate for a deviation in the usage amount of the recording material. And a print data correction method for correcting the print data by reducing the correction amount compared with the single color at the time of color mixture realized by combining respective element colors. 5. A printing apparatus for printing a color image in a plurality of element colors based on print data and attaching a recording material for each element color to a recording medium in a dot matrix form by a computer. A software recording medium that stores a print data correction program that corrects the print data to compensate for a color change based on a deviation in the amount of material used, and compensates for a deviation in the amount of recording material used for each element color. A print data correction program is characterized in that a predetermined correction amount to be set is set, and the print data is corrected by correcting the above-mentioned print data by reducing the correction amount compared with the single color when mixing colors realized by combining the element colors. Software recording medium.